CN117043038A

CN117043038A - Method and system for high integrity vehicle positioning

Info

Publication number: CN117043038A
Application number: CN202180093855.1A
Authority: CN
Inventors: B·苏巴希科; A·格伦; W·金米欧; M·德·托马斯; D·贝奇
Original assignee: Ground Transportation Systems Canada Inc
Current assignee: Ground Transportation Systems Canada Inc
Priority date: 2020-12-31
Filing date: 2021-12-29
Publication date: 2023-11-10
Also published as: WO2022144807A1; CA3203674A1; EP4271603A1

Abstract

Embodiments of a method of positioning a guideway-mounted vehicle are disclosed. In one embodiment, the communication signal is transmitted to a wayside communication device. A range estimate is obtained based on the communication signal. The radar signal is transmitted to at least one reflector. Accuracy of the range estimation is improved based on the radar signals.

Description

Method and system for high integrity vehicle positioning

Cross Reference to Related Applications

The present application is a U.S. non-provisional patent application claiming priority from U.S. provisional application No. 63/132,755, filed on 12/31/2020, and claiming priority from provisional application No. 63/173,339, filed on 4/2021, the entire contents of which are incorporated herein by reference.

Background

Driving vehicles over a wide variety of locations and environments presents challenges: determining a current location of the vehicle, tracking the location of the vehicle as the vehicle moves, and/or accurately determining a speed of the vehicle. Some locations are not suitable for conventional vehicle location and speed determination systems or methods.

Drawings

Aspects of the disclosure are best understood from the following detailed description when read with the accompanying drawing figures. Note that the various features are not drawn to scale according to standard practices in the industry. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1A is a side view of a wayside component of a high integrity vehicle positioning system according to some embodiments.

FIG. 1B is a top view of an onboard component of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 1C is a top view of a positioning method based on (a) individual distance measurements and (b) distance measurements and angle of arrival/departure measurements.

Fig. 2 is a block diagram of a wayside communication device according to some embodiments.

Fig. 3 is a block diagram of an in-vehicle communication device according to some embodiments.

Fig. 4 is a block diagram of a computer device according to some embodiments.

Fig. 5 is a block diagram of a radar system according to some embodiments.

FIG. 6 is a top view of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 7 is a top view of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 8 is a top view of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 9 is a top view of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 10 is a side view of a high integrity vehicle positioning system in accordance with some embodiments.

FIG. 11 is a side view of a high integrity vehicle positioning system in accordance with some embodiments.

Fig. 12 is a top view of an antenna of a wayside communication device and a reflector at least partially encapsulating the antenna according to some embodiments.

Fig. 13 is a range diagram of a maximum range for each of one or more range estimation techniques, according to some embodiments.

Fig. 14 is a flow chart of a method of positioning a rail mounted vehicle (guideway mounted vehicle) according to some embodiments.

Fig. 15 is a flow chart of a method of obtaining a range estimate based on a communication signal in accordance with some embodiments.

Fig. 16 is a flow chart of a method of increasing accuracy of a range estimation based on radar signals, according to some embodiments.

FIG. 17 is a flow chart of a method of positioning a rail mounted vehicle according to some embodiments.

FIG. 18 is a flowchart of a method of positioning a rail mounted vehicle according to some embodiments.

Fig. 19 is a flow chart of a method of increased accuracy of radar signal-based range estimation, according to some embodiments.

FIG. 20 is a flow chart of a method of positioning a rail mounted vehicle according to some embodiments.

Detailed Description

The following disclosure provides different embodiments or examples for implementing features of the provided subject matter. Specific examples of components, materials, values, steps, arrangements, etc. are described below to simplify the present disclosure. Of course, these are merely examples and are not limiting. Other components, materials, values, steps, arrangements, etc. are contemplated. For example, in the following description, the formation of a first feature over or on a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features such that the first and second features may not be in direct contact. Further, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Further, for ease of description, spatial relationship terms such as "below," "lower," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Embodiments of a method of positioning a guideway-mounted vehicle are disclosed. In some embodiments, one or more in-vehicle communication devices are on a rail-mounted vehicle. At various locations along the wayside of the rail, one or more wayside communication devices are placed at each location. One or more communication signals are transmitted between the one or more in-vehicle communication devices and the wayside communication device. One or more communication signals are used to determine a distance estimate between the rail mounted vehicle and the wayside communication device. In some embodiments, the distance estimate is sufficient to locate the vehicle within tens of meters. To increase the accuracy of the range estimation, one or more radar signals are transmitted to a reflector associated with the wayside communication device. The accuracy of the range estimation is improved based on radar signal return.

In some embodiments, the distance resolution of a system that uses electromagnetic signals to determine distance is given by the speed of light c divided by twice the bandwidth. The higher the bandwidth, the better the resolution and therefore the better the accuracy. In some embodiments, the communication device has a smaller bandwidth than radar, i.e., radar range measurement accuracy is better than range measurement based on the communication system. In some embodiments, the accuracy of the range estimation increases due to the inherent increase in resolution resulting from radar measurements with higher bandwidth. In some embodiments, the accuracy of the distance estimation is improved because both radar measurements and measurements made using the communication device are fed into the fusion algorithm. In some embodiments, the accuracy of the distance estimation is improved because the radar measurements are more accurate, and because the radar measurements and measurements made using the communication device are fed into the fusion algorithm.

Fig. 1A depicts a side view of a wayside component of a high integrity vehicle positioning system 100, according to some embodiments. The guideway-mounted vehicles 102 move along guideways 104 (e.g., track, rail, monorail, highway, etc.). The vehicle 102 is a train, subway, monorail, or other path-constrained vehicle, including a car or bus that has been configured to move along a constrained path.

Various locations 107 are provided along the roadside of the rail 104. In fig. 1A, at least one wayside communication device 108, at least one reflector 110 and at least one wayside radar system 111 are located at each location 107. In some embodiments, wayside communication device(s) 108, reflector(s) 110, or wayside radar system(s) 111 are not included at location(s) 107. In at least one embodiment, one or more locations 107 include a wayside communication device 108 and a reflector 110, and lack a wayside radar system 111. As explained in further detail below, in some embodiments, the communication signal is transmitted to the wayside communication device 108 when the vehicle 102 approaches the location 107. In some embodiments, the communication signal is transmitted from the wayside communication device 108 when the vehicle approaches the location 107. A vehicle location estimate is obtained based on communication signals received or transmitted by the wayside communication device 108. In some embodiments, the locations 107 are spaced at regular intervals along the roadside of the rail 104. In other embodiments, the locations 107 are not spaced at regular intervals along the roadside of the rail 104.

In some embodiments, the wayside radar system 111 is configured to transmit radar signals when the vehicle 102 is positioned in close proximity. The accuracy of the vehicle positioning estimation is improved based on the radar signals. For example, in some embodiments, vehicle location estimates obtained using radar signals are inherently more accurate than vehicle location estimates obtained using communication signals. Thus, the vehicle location estimate obtained with the communication signal is replaced with the vehicle location estimate obtained with the radar. In other embodiments, both the vehicle location estimate obtained using the communication signal and the vehicle location estimate obtained using the radar signal are input into a fusion algorithm. The fusion algorithm calculates a third and more accurate vehicle location estimate based on the vehicle location estimate obtained using the radar signal and the vehicle location estimate obtained using the communication signal.

In some embodiments, the wayside radar system 111 and the wayside communication device 108 used to obtain the vehicle location estimate are both "line-of-sight" devices. In some embodiments, the wayside radar system 111 and the wayside communication device 108 are not short-range. In some embodiments, the wayside communication device 108 is anywhere from 0 meters to hundreds of meters from the rail 104. In some open environments, the wayside communication device 108 is several meters (e.g., 10 to 20 meters) from the centerline of the rail 104. In some enclosed environments (e.g., tunnels), the wayside communication device 108 is mounted on a wall immediately adjacent to the rail 104.

In some embodiments, to obtain a vehicle location estimate based on the communication signal, a distance estimate, an angle of departure (angle of departure), and an angle of arrival (angle of arrival) are measured based on the communication signal. The distance estimation is based on a correlation between the signal-to-noise ratio and a distance between the in-vehicle communication device and the roadside communication device. The expected correlation behaves according to a poisson distribution. In some embodiments, the distance estimate based on the communication signal has an error range of a few meters. The distance estimation allows a vehicle location estimate of the vehicle 102 to be determined until a next more accurate location can be obtained. In some embodiments, the angle of departure and the angle of arrival are also measured based on the communication signal.

In some embodiments, the wayside communication signal is modulated to include a unique Identification (ID). Once the unique ID is obtained, the unique ID is used to obtain positioning data. In some embodiments, the positioning data identifies the location (e.g., latitude, longitude) of the wayside communication device 108 in a geographic coordinate system. Based on the distance estimate, the angle of arrival (AoA), and the angle of departure (AoD), a vehicle position of the vehicle 102 relative to the wayside communication device 108 is obtained. Once the positioning data is obtained, a vehicle positioning estimate is calculated that identifies the position of the vehicle 102 in the geographic coordinate system.

In some embodiments, the wayside radar signal is reflected from one or more reflective surfaces of the vehicle 102. Thus, the reflected wayside radar signal includes a unique radar signature that is used to detect that the vehicle 102 is approaching/leaving the location 107. In some embodiments, range estimates AoA and AoD are obtained based on roadside radar signals. In some embodiments, the positioning data identifies the location of the wayside radar system 111 or the wayside communication device 108 in a geographic coordinate system (e.g., latitude, longitude). Based on the distance estimate, the angle of arrival (AoA), and the angle of departure (AoD), a vehicle position of the vehicle 102 relative to the wayside communication device 108 and/or the wayside radar system 111 is obtained. Once the positioning data is obtained, a vehicle positioning estimate is calculated that identifies the position of the vehicle 102 in the geographic coordinate system.

In some embodiments, an in-vehicle radar system is mounted to the vehicle 102, as explained in further detail below. The radar signal is then transmitted to at least one reflector 110 at location 107. The reflector 110 is an object designed to reflect radar signals or a similarly strongly reflecting object with a high RCS. The accuracy of the range estimation is improved based on radar signal return. In some embodiments, reflector 110 is constructed and mounted in such a way that the spatial separation of the reflectors and the RCS as an array produce unique signatures such that location 107 is identified based on the unique signatures of the reflected radar signals (also referred to herein as radar signal returns). In some embodiments, the location of the vehicle is obtained based on the distance estimate (e.g., by time of flight (TOF) measurements) and the angle of arrival/angle of departure of the radar signals from the vehicle 102 to the reflector and back to the vehicle, the reflector RCS, and the spatial location.

In some embodiments, both the (on-board/roadside) radar and the (on-board/roadside) communication devices are RF devices. The radar is designed to measure the spatial positioning of objects relative to the radar's local coordinate system and also to measure the radial velocity of these objects. The (car-mounted/roadside) communication means are designed to transmit data wirelessly between the nodes. However, (car-mounted/roadside) communication devices are also used to determine the location of objects. In some embodiments, the accuracy of the distance estimation by the (on-board/roadside) communication device is lower than that of the radar due to bandwidth constraints, the number of antennas used by the (on-board/roadside) communication device, and the arrangement of the communication devices. However, in some embodiments, the (on-board/roadside) communication device and the radar utilize the same amount of bandwidth, and thus distance estimates with similar amounts of accuracy can be obtained. By inputting both the arrival/departure distance and the angle estimate of the radar and communication device into the fusion algorithm, the accuracy of the distance estimate is improved, as explained in further detail below. In some embodiments, the communication signal is in the frequency range of 2.4GHz-10 GHz. In some embodiments, the communication signal is a WiFi signal in a frequency band at or near 5 GHz. In some embodiments, the communication signals are 802.11 signals, such as long term evolution, LTE, signals and 5G signals. The 5G and LTE signals are in the frequency range from 450MHz to 7 GHz. In some embodiments, the 5G and LTE signals are in a frequency band near the 60GHz frequency band. In some embodiments, the radar signal is generated by automotive radar and has a frequency range between 76-81 GHz. In some embodiments, the (on-board/roadside) radar system and the (on-board/roadside) communication device differ in range resolution due to bandwidth constraints, the number of antennas, and the spatial resolution (azimuth and elevation) of the radar system and the (on-board/roadside) communication device.

Fig. 1B is a top view of an onboard component of a high integrity vehicle positioning system 100, according to some embodiments.

The onboard component of the high integrity vehicle positioning system 100 is an onboard component on or in the vehicle 102. The high integrity vehicle positioning system 100 includes one or more in-vehicle communication devices 120 and one or more radar systems 122. In fig. 1B, one of the in-vehicle communication devices 120 is located at one end 124 of the vehicle 102, and the other of the in-vehicle communication devices 120 is located at the other end 126 of the vehicle 102. End 125 is opposite end 126. Further, both end portions are perpendicular to the traveling direction (t+, T-) of the vehicle 102.

Each in-vehicle communication device 120 and each radar system 122 is communicatively associated with a computer device 124. The computer device 124 is configured to operate the high integrity vehicle positioning system 100 to determine high accuracy positioning data identifying the positioning of the vehicle 102.

The in-vehicle communication device 120 is configured to transmit communication signals to the roadside communication device 108 (see fig. 1A) or to receive communication signals from the roadside communication device 108. In some embodiments, the in-vehicle communication device 120 transmits communication signals to the wayside communication device 108. The wayside communication device 108 then transmits the data back to the on-board communication device 120. The distance between the in-vehicle communication device 120 and the wayside communication device 108 is estimated based on the transmitted communication or using the measurement based on the communication signal to determine a distance estimate. In some embodiments, the wayside communication device 108 transmits the communication signal and the in-vehicle communication device 120 is configured to obtain a measurement (e.g., a signal-to-noise measurement) to obtain the distance estimate. In some embodiments, the wayside communication device 108 transmits another communication signal as a reply to the communication signal transmitted by the in-vehicle communication device 120. The distance estimate is based on the amount of time it takes for the communication signal generated by the in-vehicle communication device 120 to reach the wayside communication device 108 and return to the in-vehicle communication device 120. In some embodiments, the in-vehicle communication device 120 transmits a communication signal and the wayside communication device 108 is configured to obtain a measurement (e.g., a signal-to-noise measurement) to obtain a distance estimate. In some embodiments, the in-vehicle communication device 120 transmits another communication signal as a reply to the communication signal transmitted by the wayside communication device 108. The distance estimate is based on the amount of time it takes for the communication signal generated by the wayside communication device 108 to reach the in-vehicle communication device 120 and return to the wayside communication device 108. The range is estimated independently by the on-board and roadside communication devices, and each device knows the distance estimated by its peer. In some embodiments, the distance estimate, aoA, and AoD are obtained based on an in-vehicle communication signal. Based on the distance estimates, aoA, and AoD, a vehicle position of the vehicle 102 relative to the wayside communication device 108 and/or the wayside radar system 111 is obtained. Once the positioning data associated with the position 107 is obtained, a vehicle positioning estimate is calculated that identifies the position of the vehicle 102 in the geographic coordinate system.

In some embodiments, the wayside communication device 108 functions as a landmark and transmits a unique ID (e.g., wayside radio n), wherein the range estimate of the wayside communication device 108 is determined based on the communication signal carrying the unique ID. The location data identifying the wayside communication device 108 is then looked up (e.g., in a database or stored table) based on the unique ID. In some embodiments, a signal-to-noise ratio distance estimation technique (e.g., a Received Signal Strength Indicator (RSSI)) is used to determine a distance estimate from the wayside communication device 108 to the vehicle 102 based on a measured distance between the on-board communication device 120 of the vehicle and the wayside communication device 108. The location of the vehicle 102 is estimated based on the location data identifying the wayside communication device 108 and the distance estimate from the wayside communication. In some embodiments, the signal-to-noise ratio is expressed in terms of poisson's distribution as a function of the distance between the in-vehicle communication device 120 and the wayside communication device 108. In some embodiments, the distance estimate is low-precision (e.g., tens of meters). In some embodiments, the wayside communication device 108 and the in-vehicle communication device 120 are configured to generate a distance estimate when the communication signal is used to identify the reflector 110 associated with the wayside communication device 108 in the area of the particular location 107. The wayside communication device 108 and the in-vehicle communication device 120 generate the communication signals according to an 802.11 communication protocol that includes Wi-Fi, LTE, 5G, bluetooth, or UWB protocols. In at least some embodiments, a communication protocol other than an 802.11 communication protocol is used for communication signals.

In some embodiments, the area with the reflector 110 is determined by the association between the antennas of the wayside communication device 108 and the reflector 110. The Received Signal Strength Indicator (RSSI) creates a window or region where the reflector 110 is expected to reside. In some embodiments, the window/region is narrowed by precisely measuring the round trip time (FM RTT). In some embodiments, more accurate measurements are obtained by radar system 122, wherein the arrangement of reflectors 110 is classified based on Radar Cross Section (RCS) of reflectors 110.

In some embodiments, the distance estimate is obtained using a TOF distance estimation technique, such as precisely measuring round trip time (FM RTT), which determines the distance based on known values of measured TOF and speed of light. In some embodiments, the distance estimate is obtained using angle of arrival and/or angle of departure measurements.

The reflector 110 has any suitable shape. In some embodiments, reflector 110 comprises a retroreflector (retroreflector) that is a cube-sided retroreflector, a triangle-sided retroreflector, a hemispherical (dish) retroreflector, or other shape used in conjunction with radar systems.

In some embodiments, the reflector 110 is mounted near the wayside communication device 108, an antenna of the wayside communication device 108 and/or an antenna array of the wayside communication device 108. In some embodiments, the reflector 110 is a radome (radome) that at least partially encapsulates an antenna of the wayside communication device 108. In some embodiments, the reflectors 110 at each location 107 are formed as an array of reflectors 110. In some embodiments, the array of reflectors 110 includes reflectors 110 of different shapes and/or different sizes. The reflector shape and size affect the radar measured reflector RCS, a key attribute in the reflector classification algorithm.

In some embodiments, the array of reflectors 110 is configured in a geometric arrangement that produces unique or semi-unique Radio Frequency (RF) signatures in the RCS aspect of the radar system. In some embodiments, the geometric arrangement includes reflectors at different heights above ground level relative to the wayside communication device antenna at particular locations. In some embodiments, the geometric arrangement includes reflectors 110 at different longitudinal positions (positions along the rail 104) of the wayside communication device antenna or antenna array relative to the wayside communication device 108 at a particular location 107. In some embodiments, the geometric arrangement includes reflectors 110 at different lateral positions (perpendicular to the predefined path 104) relative to a wayside communication device antenna or antenna array of the wayside communication device 108 at a particular location 107.

In some embodiments, a plurality of vehicle positioning estimates are obtained from a plurality of wayside communication devices 108 and a plurality of in-vehicle communication devices 120. In some embodiments, at each location 107, there is a one-to-one correspondence between the in-vehicle communication device 120 and the wayside communication device 108. In other words, each in-vehicle communication device obtains a range estimate for a different and particular one of the wayside communication devices 108 at a particular location. In some embodiments, each in-vehicle communication device 108 obtains a vehicle location estimate at each roadside communication device 108 at each location 107. In some embodiments, some, but not all, of the wayside communication devices 108 at each location 107 in each in-vehicle communication device 120 are utilized to obtain vehicle location estimates. In some embodiments, various vehicle location estimates are fused using a fusion algorithm to obtain more accurate vehicle location estimates.

In some embodiments, the vehicle 102 includes a single in-vehicle communication device 120, and each location 107 includes a plurality of wayside communication devices 108. A single in-vehicle communication device 120 is configured to obtain vehicle location estimates from each roadside communication device 108 at each location 107. In some embodiments, each vehicle 102 includes a plurality of in-vehicle communicators 120, and each location 107 includes a single wayside communicator 108. The plurality of in-vehicle communication devices 120 are each configured to obtain a vehicle location estimate from a single wayside communication device 108. In some embodiments, the vehicle 102 includes a single in-vehicle communication device 120, and each location 107 includes a single wayside communication device 108. The single in-vehicle communication device 120 is configured to obtain a vehicle location estimate from the single wayside communication device 108. These and other configurations are within the scope of the present disclosure.

The vehicle location estimate obtained using the communication signals provides sufficient location for the vehicle 102 until its accuracy can be improved using the radar systems 111, 122. As described above, the radar systems 111, 122 are used to transmit radar signals to increase the accuracy of distance and angular position (AoA/AoD) estimation based on radar signal returns. In some embodiments, the reflector arrays of different sizes and/or locations are configured to reflect radar signals from the in-vehicle radar system 122 at a predetermined Radar Cross Section (RCS) (or equivalent intensity attribute if LiDAR is used) with respect to each roadside communication device antenna or antenna array of the roadside communication device 108. The predefined RCS is stored in a database along with highly accurate positioning data that identifies the particular positioning 107 associated with the predefined RCS. Highly accurate positioning data is used in conjunction with one or more TOF and AoA/AoD measurements from the reflector 110 to obtain a more accurate distance estimate for the vehicle 102.

In some embodiments, radar system 111 and/or radar system 122 include a commercial off-the-shelf (COTS) three-dimensional (3-D) automotive radar system and/or a four-dimensional (4-D) imaging radar system. In some embodiments, the COTS 3-D radar is configured to measure the distance, relative radial doppler velocity (relative reference frame from the radar system), and angular position of the reflector 110 within the field of view (FOV) at a particular location 107. In some embodiments, the 3-D COTS radar system has no beam steering capability or very limited beam steering capability. In some embodiments, the angular position (i.e., azimuth angle, not elevation angle) of reflector 110 is measured only in the horizontal plane.

In some embodiments, the 4-D radar system has good beam steering capabilities and is operable to generate a point cloud image of the reflector 110 within the FOV of the 4-D radar system. In some embodiments, the 4-D radar system is configured to measure the distance, relative radial Doppler velocity, and angular position of the reflector 110 within the radar FOV. In some embodiments, the angular position includes both azimuth and elevation angles relative to a relative reference coordinate system of the radar system. In some embodiments, the 4-D radar system is configured to measure reflected radar signals that provide high performance resolution and high accuracy measurements of the reflector 110. For example, in some embodiments, a 4-D radar system has a range resolution of 10cm at distances up to 50m and a range resolution of 50cm at distances greater than 50 m. In some embodiments, the 4-D radar system has a maximum distance of at least 50m, and in some cases, greater than 150 m. In some embodiments, the 4-D radar system has an angular resolution of better than 1. In some embodiments, 4-D radar systems typically have both beam forming and beam steering capabilities. In some embodiments, the COTS 3-D radar system has a range and speed resolution similar to a 4-D radar system. However, in some embodiments, COTS 3-D radar systems have a worse angular resolution than 4-D radar systems and cannot measure elevation angle. Furthermore, in some embodiments, the COTS 3-D radar system does not have beamforming or beam steering capabilities.

In some embodiments, radar system 111 and/or radar system 122 are configured to generate radar signals within a frequency band of 76GHz to 81 GHz. In some embodiments, radar system 111 and/or radar system 122 include a light detection and ranging (LiDAR) radar system. In some embodiments, the LiDAR radar system is a coherent LiDAR, an incoherent LiDAR, a mechanical LiDAR, a phased array LiDAR, or a flashing LiDAR. In some embodiments, radar system 111 and/or radar system 122 are configured to include a camera to increase the accuracy of the distance estimation.

In some embodiments, the antenna of the wayside communication device 108 is used in place of the retro-reflector array, the antenna being reflective in the radar system band and transparent in the communication system band if the antenna is detectable by the radar system 122. In some embodiments, radar system 122 is a LiDAR or camera. In some embodiments, the radar system 122 detects the antenna arrangement of the wayside communication device 108. For example, in some embodiments, radar system 122 is a 4-D radar that detects a roadside communicator antenna or antenna array arrangement. In some embodiments, the radar system 122 does not detect the antennas of the wayside communication device 108. For example, in some embodiments, radar system 122 is a COTS 3-D radar and does not detect a roadside communicator antenna or antenna array arrangement. In some embodiments, an association is made between the reflector 110 and the wayside communication device 108. In some embodiments, the distance, angle of arrival, and angle of departure to the wayside communication device are measured by the in-vehicle communication device. In some embodiments, the relative position of the guideway-mounted vehicle 102 is compared to the radar-measured distance to the reflector, angle of arrival, and angle of departure. If the two are within some acceptance threshold and the reflector tag (RCS) matches the expected tag (based on wayside communication device positioning), then the association is confirmed and the location is determined. In some embodiments, the reflector 110 is a frequency selective radome at the antennas of the wayside communication device 108.

In some embodiments, the location of the vehicle 102 relative to the wayside communication device 108 is determined. The distance of the vehicle 102 from the wayside communication device 108 is estimated using one or more communication signals based on RSSI and/or FM RTT distance estimation techniques that, in some embodiments, are augmented by an angle of arrival/departure and a wayside communication device ID.

Additionally, in some embodiments, the array of reflectors 110 is arranged to reflect radar signals such that the reflected radar signals have unique radar signatures. The unique radar signature of the reflected radar signal is detected to check whether the reflected radar signal RCS matches the reflector RCS. In some embodiments, the unique radar signature is a unique signature of the reflector array. Thus, since the unique mark is used to identify the reflector 110, a stored location of the reflector is obtained. The location of the vehicle 102 is determined based on the stored locations of the reflectors 110 (or the wayside communication device 108), the distance measurements, the angle of arrival and departure radar measurements, and a confirmation that the corresponding reflector signatures match the expected signatures.

In some embodiments, the digital version of the unique tag is transmitted to a server to find a match in a database. Once a match is found, the location data associated with the identified reflector and the position of the train relative to the reflector are used to identify the location of the vehicle 102. In this way, the location of the wayside communication device is used to identify the location of the reflector 110 that produced the unique radar signature.

In some embodiments, vehicle location estimates obtained using communication signals from the in-vehicle communication device 120, vehicle location estimates obtained using communication signals from the wayside communication device 108, vehicle location estimates obtained using radar signals from the in-vehicle radar system 122, and/or vehicle location estimates obtained using radar signals from the wayside radar system 111 are compared to one another to determine if the difference between the vehicle location estimates is within a defined error range. In some embodiments, the error range is defined by parameters such as speed and time. In some embodiments, the error range is defined by safety standards, such as EN 50129 and EN 50126. For example, assume that a train moves at 10 meters/second. Further, assume that the train positioning is determined by the wayside system at time t 1 and then received at the on-board system at time t2=t1+1 seconds. In addition, assume that the train positioning is determined by the wayside system at time t3=t1+1.5 seconds. In some embodiments, the error range is greater than err=10 meters/second×1.5 seconds+ tolerance, where tolerance represents positioning estimation accuracy.

In some embodiments, if the difference between the vehicle positioning estimates is within a defined error range, the position of the vehicle is known with sufficient accuracy to account for a high level of safety integrity (i.e., SIL 4). In some embodiments, if the difference between the vehicle positioning estimates is not within a defined error range, the position of the vehicle is not known to sufficient accuracy to be considered to have a lower safety integrity level than SIL 4. In some embodiments, specialized safety procedures and precautions are implemented in response to determining that the difference between the vehicle location estimates is not within a defined error range.

Fig. 1C is a block diagram of a rail mounted vehicle 102 and two wayside communication devices 108A, 108B.

The in-vehicle communication device 120 is mounted in the vehicle 102. The centerline CL of the vehicle 102. The center line CL is parallel to the traveling direction t+. The wayside communication device 108A is on one side of the centerline CL and the wayside communication device 108B is on the other side of the centerline CL.

Fig. 1C is a diagram of obtaining two distance measurements R1 and R2 between an in-vehicle communication device 120 and roadside communication devices 108A, 108B. The distance measurement R1 is to the roadside communication device 108A and the distance measurement R2 is to the roadside communication device 108B. One technique for determining the position of the vehicle 102 without angle information about the communication signals is by using two different distance measurements R1 and R2 with the wayside communication devices 108A, 108B in a separate position. Circle C1 represents a possible location of the train knowing only the distance R1 from wayside unit 108A. Circle C2 represents a possible location of vehicle 102 that is only aware of distance R2 from wayside communication device 108B. Thus, assuming that the direction of motion of the vehicle 102 is known, the intersection of the two circles C1, C2 at the convergence point (labeled in fig. 1C) is the position of the vehicle. However, the in-vehicle communication device 120 and/or the wayside communication devices 108A, 108B are also configured to utilize a single distance measurement (R1 or R2) to measure the location of the train, as well as to measure angle information such as AoD/AoA. In fig. 1C, aoD of R1 with respect to the center line CL is measured as α1. Knowing that both R1 are α1, the position of the vehicle 102 is determined. AoD of R2 with respect to the centerline CL is measured to be α2. Knowing that both R2 are α2 determines the position of the vehicle 102.

Fig. 2 is a block diagram of a wayside communication device 200 according to some embodiments.

In some embodiments, each of the wayside communication devices 108 in fig. 1A has the configuration of the wayside communication device 200 as shown in fig. 2.

In some embodiments, the wayside communication device 200 comprises a general purpose computing device comprising a hardware processor 202 and a non-transitory computer readable storage medium 204. The computer-readable storage medium 204 is encoded with (i.e., stores) computer program code 206, i.e., a set of executable instructions. Execution of the computer program code 206 by the hardware processor 202 represents (at least in part) a vehicle positioning and speed determination tool that implements some or all of the methods described herein (hereinafter referred to as processes and/or methods) in accordance with one or more embodiments.

The processor 202 is electrically coupled to a computer-readable storage medium 204 via a bus 208. The processor 202 is also electrically coupled to an I/O interface 210 via a bus 208. Wireless communication device 212 is also electrically coupled to processor 202 through bus 208. The wireless communication device 212 is connected to a network 214 such that the processor 202 and the computer readable storage medium 204 can be connected to external elements via the network 214. The processor 202 is configured to execute computer program code 206 encoded in the computer readable storage medium 204 to make available the wayside communication device 200 for performing some or all of the described processes and/or methods. In one or more embodiments, processor 202 is a Central Processing Unit (CPU), multiprocessor, distributed processing system, application Specific Integrated Circuit (ASIC), and/or suitable processing unit.

In one or more embodiments, the computer-readable storage medium 204 is an electronic, magnetic, optical, electromagnetic, infrared, and/or semiconductor system (or apparatus or device). For example, computer-readable storage media 204 includes semiconductor or solid state memory, magnetic tape, removable computer diskette, random Access Memory (RAM), read-only memory (ROM), rigid magnetic disk and/or optical disk. In one or more embodiments using optical disks, the computer-readable storage medium 204 includes a compact disk read only memory (CD-ROM), compact disk read/write (CD-R/W), and/or Digital Video Disk (DVD).

In one or more embodiments, the computer readable storage medium 204 stores computer program code 206, the computer program code 206 configured to make the wayside communication device 200 available to perform some or all of the described processes and/or methods. In one or more embodiments, the computer-readable storage medium 204 also stores information that facilitates performing a portion or all of the noted processes and/or methods. In one or more embodiments, the computer-readable storage medium 204 stores a library 207 of parameters (e.g., vehicle location estimate, distance estimate, location data, signal data, TOF data, angle of arrival, angle of departure) as disclosed herein.

The wayside communication device 200 comprises an I/O interface 210. The I/O interface 210 is coupled to external circuitry. In one or more embodiments, the I/O interface 210 includes a keyboard, a keypad, a mouse, a trackball, a trackpad, a touch screen, and/or cursor direction keys for communicating information and commands to the processor 202.

The wayside communication device 200 also comprises a wireless communication device 212 coupled to the processor 202. The wireless communication device 212 allows the wayside communication device 200 to communicate with a network 214 to which one or more other computer systems are connected. The wireless communication device 212 includes a wireless network interface such as bluetooth, WIFI, LTE, 5G, WIMAX, GPRS, or WCDMA. In one or more embodiments, some or all of the described processes and/or methods are implemented in two or more bypass communication devices 200.

The wayside communication device 200 is configured to receive the information through the I/O interface 210. The information received through the I/O interface 210 includes one or more of instructions, data, and/or other parameters for processing by the processor 202. Information is transferred to processor 202 via bus 208. The wayside communication device 200 is configured to receive the information related to the UI through the I/O interface 210. This information is stored in the computer readable storage medium 204 as a User Interface (UI) 242.

The wireless communication device 212 is configured to receive the communication signals 250 via the one or more antennas 220. In some embodiments, communication signal 250 comprises a carrier signal modulated with one or more information-bearing signals. In some embodiments, wireless communication device 212 is configured to demodulate communication signal 250 such that information of the information-bearing signal is obtained. In some embodiments, the information of the information-bearing signal is transformed into parameters in the library 207, which may be read by a computer and stored in the computer-readable storage medium 204.

In some embodiments, the wireless communication device 212 is configured to transmit a communication signal 252, the communication signal 252 being configured to obtain the distance and AoA/AoD estimates via the one or more antennas 220. In other embodiments, the wireless communication device 212 is configured to receive a communication signal 250 carrying distance and AoA/AoD estimation data indicative of a distance estimate obtained based on the communication signal 252.

In some embodiments, some or all of the mentioned processes and/or methods are implemented as stand-alone software applications executed by a processor. In some embodiments, some or all of the mentioned processes and/or methods are implemented as software applications as part of an additional software application. In some embodiments, some or all of the mentioned processes and/or methods are implemented as plug-ins to a software application.

In some embodiments, the process is implemented as a function of a program stored in a non-transitory computer-readable recording medium. Examples of the non-transitory computer readable recording medium include, but are not limited to, external/removable and/or internal/built-in storage or memory units, for example, one or more optical disks such as DVDs, magnetic disks such as hard disks, semiconductor memories such as ROMs, RAMs, memory cards, and the like.

Fig. 3 is a block diagram of an in-vehicle communication device 300, according to some embodiments.

In some embodiments, each in-vehicle communication device 120 in fig. 1B has a configuration of in-vehicle communication device 300 as shown in fig. 3.

In some embodiments, the in-vehicle communication device 300 includes a general purpose computing device including a hardware processor 302 and a non-transitory computer readable storage medium 304. The computer-readable storage medium 304 is encoded with (i.e., stores) computer program code 306, i.e., a set of executable instructions, among other things. Execution of the computer program code 306 by the hardware processor 302 represents (at least in part) a vehicle positioning and speed determination tool that implements a portion or all of the methods described herein (hereinafter referred to as processes and/or methods) in accordance with one or more embodiments.

The processor 302 is electrically coupled to a computer-readable storage medium 304 via a bus 308. The processor 302 is also electrically coupled to an I/O interface 310 through a bus 308. Wireless communication device 312 is also electrically coupled to processor 302 via bus 308. The wireless communication device 312 is connected to a network 314 such that the processor 302 and the computer-readable storage medium 304 can be connected to external elements via the network 314. The processor 302 is configured to execute computer program code 306 encoded in the computer readable storage medium 304 in order to make available the in-vehicle communication device 300 for performing part or all of the described processes and/or methods. In one or more embodiments, processor 302 is a Central Processing Unit (CPU), multiprocessor, distributed processing system, application Specific Integrated Circuit (ASIC), and/or suitable processing unit.

In one or more embodiments, the computer-readable storage medium 304 is an electronic, magnetic, optical, electromagnetic, infrared, and/or semiconductor system (or apparatus or device). For example, computer-readable storage media 304 includes semiconductor or solid state memory, magnetic tape, removable computer diskette, random Access Memory (RAM), read-only memory (ROM), rigid magnetic disk and/or optical disk. In one or more embodiments using optical disks, computer-readable storage medium 304 includes compact disk read-only memory (CD-ROM), compact disk read/write (CD-R/W), and/or Digital Video Disk (DVD).

In one or more embodiments, the computer readable storage medium 304 stores computer program code 306, the computer program code 306 configured to make the in-vehicle communication device 300 available to perform some or all of the mentioned processes and/or methods. In one or more embodiments, the computer-readable storage medium 304 also stores information that facilitates performing a portion or all of the mentioned processes and/or methods. In one or more embodiments, the computer-readable storage medium 304 stores a library 307 of parameters (e.g., vehicle location estimate, distance estimate, location data, signal data, TOF data, angle of arrival, angle of departure) as disclosed herein.

The in-vehicle communication device 300 includes an I/O interface 310. The I/O interface 310 is coupled to external circuitry. In one or more embodiments, the I/O interface 310 includes a keyboard, a keypad, a mouse, a trackball, a trackpad, a touch screen, and/or cursor direction keys for communicating information and commands to the processor 302.

The in-vehicle communication device 300 also includes a wireless communication device 312 coupled to the processor 302. The wireless communication device 312 allows the in-vehicle communication device 300 to communicate with a network 314 to which one or more other computer systems are connected. The wireless communication device 312 includes a wireless network interface such as bluetooth, WIFI, LTE, 5G, WIMAX, GPRS, or WCDMA. In one or more embodiments, some or all of the processes and/or methods are implemented in two or more in-vehicle communication devices 300.

The system 300 is configured to receive information via the I/O interface 310. The information received through I/O interface 310 includes one or more of instructions, data, and/or other parameters for processing by processor 302. This information is transferred to processor 302 via bus 308. The in-vehicle communication device 300 is configured to receive information related to the UI through the I/O interface 310. This information is stored in computer-readable storage medium 304 as User Interface (UI) 342.

The wireless communication device 312 is configured to receive the communication signals 350 via the one or more antennas 320. In some embodiments, communication signal 350 includes a carrier signal modulated with one or more information-bearing signals. In some embodiments, the wireless communication device 312 is configured to demodulate the communication signal 350 such that information of the information-bearing signal is obtained. In some embodiments, the information of the information-bearing signal is transformed into parameters in the library 307, which may be read by a computer and stored in the computer-readable storage medium 304.

In some embodiments, the wireless communication device 312 is configured to transmit a communication signal 352, the communication signal 352 being configured to obtain the distance and AoA/AoD estimate via the one or more antennas 320. In other embodiments, the wireless communication device 312 is configured to receive a communication signal 350 carrying distance and AoA/AoD estimation data indicating a distance estimate obtained based on the communication signal 352.

Fig. 4 is a block diagram of a computer device 400, according to some embodiments.

In some embodiments, computer device 124 in fig. 1B has the configuration of computer device 400 as shown in fig. 4.

In some embodiments, computer device 400 includes a general purpose computing device including a hardware processor 402 and a non-transitory computer readable storage medium 404. The computer-readable storage medium 404 is encoded with (i.e., stores) computer program code 406, i.e., a set of executable instructions, among other things. Execution of the computer program code 406 by the hardware processor 402 represents (at least in part) a vehicle positioning and speed determination tool that implements some or all of the methods described herein (hereinafter referred to as processes and/or methods) in accordance with one or more embodiments.

The processor 402 is electrically coupled to a computer readable storage medium 404 via a bus 408. The processor 402 is also electrically coupled to an I/O interface 410 via a bus 408. Network device 412 is also electrically connected to processor 402 through bus 408. Network device 412 is connected to network 414 such that processor 402 and computer readable storage medium 404 can be connected to external elements via network 414. The processor 402 is configured to execute computer program code 406 encoded in the computer readable storage medium 404 to make the system 400 available to perform a portion or all of the processes and/or methods. In one or more embodiments, processor 402 is a Central Processing Unit (CPU), multiprocessor, distributed processing system, application Specific Integrated Circuit (ASIC), and/or suitable processing unit.

In one or more embodiments, the computer-readable storage medium 404 is an electronic, magnetic, optical, electromagnetic, infrared, and/or semiconductor system (or apparatus or device). For example, computer-readable storage media 404 includes semiconductor or solid state memory, magnetic tape, removable computer diskette, random Access Memory (RAM), read-only memory (ROM), rigid magnetic disk and/or optical disk. In one or more embodiments using optical disks, computer-readable storage medium 404 includes a compact disk read only memory (CD-ROM), compact disk read/write (CD-R/W), and/or Digital Video Disk (DVD).

In one or more embodiments, the computer readable storage medium 404 stores computer program code 406, the computer program code 406 configured to make the computer apparatus 400 available to perform some or all of the mentioned processes and/or methods. In one or more embodiments, the storage medium 404 also stores information that facilitates performing some or all of the processes and/or methods mentioned. In one or more embodiments, the computer-readable storage medium 404 stores a library 407 of parameters (e.g., vehicle location estimate, distance estimate, location data, signal data, TOF data, angle of arrival, angle of departure, radar signature, azimuth, zenith, elevation) as disclosed herein.

Computer device 400 includes an I/O interface 410. The I/O interface 410 is coupled to external circuitry. In one or more embodiments, the I/O interface 410 includes a keyboard, a keypad, a mouse, a trackball, a trackpad, a touch screen, and/or cursor direction keys for communicating information and commands to the processor 402.

Computer device 400 also includes a network device 412 coupled to processor 402. Network device 412 allows computer device 400 to communicate with a network 414 to which one or more other computer systems are connected. Network device 412 includes a wireless network interface such as Bluetooth, WIFI, LTE, 5G, WIMAX, GPRS, or WCDMA, or a wired network interface such as ETHERNET, USB, or IEEE-1364. In one or more embodiments, some or all of the processes and/or methods mentioned are implemented in two or more computer devices 400.

Computer device 400 is configured to receive information via I/O interface 410. The information received through I/O interface 410 includes one or more of instructions, data, and/or other parameters for processing by processor 402. This information is transferred to processor 402 via bus 408. The computer device 400 is configured to receive information related to the UI through the I/O interface 410. This information is stored in the computer-readable storage medium 404 as a User Interface (UI) 442.

In some embodiments, the process is implemented as a function of a program stored in a non-transitory computer-readable recording medium. Examples of the non-transitory computer readable recording medium include, but are not limited to, external/removable and/or internal/built-in storage or memory units, for example, such as one or more optical disks, magnetic disks such as DVDs, magnetic disks such as hard disks, semiconductor memories such as ROMs, RAMs, memory cards.

Fig. 5 is a block diagram of a radar system 500, according to some embodiments.

In some embodiments, radar system 111 in fig. 1A has a configuration of radar system 500 as shown in fig. 5. In some embodiments, each radar system 122 in fig. 1B has a configuration of radar system 500 as shown in fig. 5.

In some embodiments, radar system 500 includes a general purpose computing device including a hardware processor 502 and a non-transitory computer readable storage medium 504. The computer-readable storage medium 504 is encoded with (i.e., stores) computer program code 506, i.e., a set of executable instructions, among other things. Execution of the computer program code 506 by the hardware processor 502 represents (at least in part) a vehicle positioning and speed determination tool that implements a portion or all of the methods described herein (hereinafter referred to as processes and/or methods) in accordance with one or more embodiments.

The processor 502 is electrically coupled to a computer readable storage medium 504 via a bus 508. The processor 502 is also electrically coupled to an I/O interface 510 via a bus 508. Network device 512 is also electrically coupled to processor 502 through bus 508. Network device 512 is connected to network 514 such that processor 502 and computer readable storage medium 504 can be connected to external elements via network 514. The processor 502 is configured to execute computer program code 506 encoded in a computer readable storage medium 504 to make the radar system 500 available to perform some or all of the described processes and/or methods. In one or more embodiments, the processor 502 is a Central Processing Unit (CPU), multiprocessor, distributed processing system, application Specific Integrated Circuit (ASIC), and/or suitable processing unit.

Radar system 500 includes one or more radar antennas 515 (front-end) and a radar signal processing unit 517 configured to generate radar signals (chirps) 550 and process reflected radar signals 550. The radar signal processing unit 517 is connected to the processor 502 through the bus 508. In some embodiments, radar signal processing unit 517 includes a digital-to-analog converter to convert digital signals or information from processor 502 to radar signal 550.

In one or more embodiments, the computer-readable storage medium 504 is an electronic, magnetic, optical, electromagnetic, infrared, and/or semiconductor system (or apparatus or device). For example, computer-readable storage media 504 includes semiconductor or solid state memory, magnetic tape, removable computer diskette, random Access Memory (RAM), read-only memory (ROM), rigid magnetic disk and/or optical disk. In one or more embodiments using optical disks, computer-readable storage medium 504 includes a compact disk read-only memory (CD-ROM), compact disk read/write (CD-R/W), and/or Digital Video Disk (DVD).

In one or more embodiments, the computer-readable storage medium 504 stores computer program code 506, the computer program code 506 configured to make the radar system 500 available to perform some or all of the mentioned processes and/or methods. In one or more embodiments, the computer-readable storage medium 504 also stores information that facilitates performing some or all of the processes and/or methods mentioned. In one or more embodiments, the computer-readable storage medium 504 stores a library 507 of parameters (e.g., TOF data, angle of arrival, angle of departure, radar signature, azimuth, zenith, elevation) as disclosed herein.

Radar system 500 includes I/O interface 510. The I/O interface 510 is coupled to external circuitry. In one or more embodiments, the I/O interface 510 includes a keyboard, a keypad, a mouse, a trackball, a trackpad, a touch screen, and/or cursor direction keys for communicating information and commands to the processor 502.

Radar system 500 also includes a network device 512 coupled to processor 502. Network device 512 allows radar system 500 to communicate with a network 514 to which one or more other computer systems are connected. Network device 512 includes a wireless network interface such as Bluetooth, WIFI, LTE, 5G, WIMAX, GPRS, or WCDMA, or a wired network interface such as ETHERNET, CAN bus, USB, or IEEE-1364. In one or more embodiments, some or all of the mentioned processes and/or methods are implemented in two or more radar systems 500.

Radar system 500 is configured to receive information through I/O interface 510. The information received through I/O interface 510 includes one or more of instructions, data, and/or other parameters for processing by processor 502. Information is transferred to processor 502 through bus 508. Radar system 500 is configured to receive information related to the UI through I/O interface 510. This information is stored in the computer-readable storage medium 504 as a User Interface (UI) 542.

Fig. 6-11 illustrate a high integrity vehicle positioning system with different arrangements for reflectors 110. In addition to the RCS of the reflector 110, the different positions of the reflector relative to the antennas of the wayside communication device 108 are used as a classification technique to promote the positioning algorithm. In some embodiments, the location is based on two key attributes (a) a unique identification of the location 107 based on the arrangement of reflectors 110 and (b) an accurate estimate of the position of the vehicle relative to the location 107. In some embodiments, the relative position of the reflector 107 with respect to the antenna of the wayside communication device 108 and the RCS of the reflector 110 are used to identify or verify the identity of the wayside communication device 108 and, thus, the location 107. In some embodiments, the location of the location 107 is stored and then looked up once the vehicle locating system detects the wayside communication device 108 associated with the location 107. Then, given the position of location 107 and the position of vehicle 102 relative to location 107, the position of vehicle 102 is determined.

Fig. 6 is a top view of a high integrity vehicle positioning system 600, according to some embodiments.

The high integrity vehicle positioning system 600 includes an onboard communication device 620 and a radar 622, which may be a frequency modulated continuous wave (FM CW) radar or a non-FM CW radar using other modulation (encoding) techniques on the vehicle 102. In some embodiments, the in-vehicle communication device 620 corresponds to the in-vehicle communication device 120 shown in fig. 1B, and the radar 622 corresponds to the radar system 122 in fig. 1A.

In this embodiment, the rail 104 extends in a direction parallel to the X-axis. One side of the rail is labeled as the a side and the other side of the rail is labeled as the B side. The a-side and the B-side are offset with respect to a second direction parallel to the Y-axis. The Y-axis is perpendicular to the X-axis.

At location 607 on the a-side of the wayside of the guideway 104, the high integrity vehicle positioning system 600 includes a wayside communicator 608A and three reflectors, labeled reflector 1A, reflector 2A and reflector 3A. In some embodiments, the wayside communication device 608A corresponds to one of the wayside communication devices 108 in fig. 1A at a particular location 107. Each of the reflectors 1A, 2A, 3A corresponds to the reflector 110 in fig. 1A.

At location 607 on the B side of the wayside of rail 104, high integrity vehicle positioning system 600 includes wayside communication device 608B and three B side reflectors, labeled reflector 1B, reflector 2B, reflector 3B. The roadside communication device 608A and the roadside communication device 608B are collectively referred to as the roadside communication device 608. In some embodiments, the wayside communication device 608B corresponds to one of the wayside communication devices 108 in fig. 1A at a particular location 107. Each of the reflectors 1B, 2B, 3B corresponds to the reflector 110 in fig. 1A.

In fig. 6, each of the reflectors 1A, 2A, 3A on the a side is aligned with respect to the Y axis and offset with respect to the X axis. In this example, the reflector 1A, the reflector 2A, the reflector 3A on the a side all have the same tetrahedral shape. Each of the reflectors 1A, 2A, 3A on side a is associated with a wayside communication device 608A on side a of the rail 104.

In fig. 6, each of the reflectors 1B, 2B, 3B on the B side is aligned with respect to the Y axis and offset with respect to the X axis. In this example, the reflector 1B, the reflector 2B, the reflector 3B on the B side all have the same tetrahedral shape. Each of the reflectors 1B, 2B, 3B on the B side is associated with a roadside communication device 608B on the B side of the rail 104.

In this embodiment, the arrangement of the reflectors 1A, 2A, and 3A on the a side is the same as the arrangement of the reflectors 1B, 2B, and 3B on the B side.

The high integrity vehicle positioning system 600 is configured to obtain various distance and AoA/AoD measurements labeled R1, R2, R4, R5, R7, R8, R9, R10, R11, R12, α3, α6, α7, α8, α9, α10, α11, and α12.

R1 is a distance estimate obtained by the in-vehicle communication device 620 using RSSI in combination with the communication signal transmitted to the roadside communication device 608A. When the train approaches the wayside communication device 608, a first rough distance estimate is performed using RSSI based on a desired signal-to-noise ratio distribution (poisson distribution) regarding the distance between the on-board communication device and the wayside communication device.

R2 is a distance estimate obtained by the in-vehicle communication device 620 using the FM RTT in combination with the communication signal transmitted to the roadside communication device 608A. The FM RTT is based on the round-trip time of flight between the in-vehicle communication device 620 and the wayside communication device 608A.

α3 is an angle of arrival and/or angle of departure estimate obtained by the in-vehicle communication device 620 using a communication device multiple-input multiple-output (MIMO) antenna structure in combination with the communication signals transmitted to the wayside communication device 608A.

R4 is a distance estimate obtained by the in-vehicle communication device 620 using the RSSI in combination with the communication signal transmitted to the roadside communication device 608B.

R5 is a distance estimate obtained by the in-vehicle communication device 620 using the FM RTT in combination with a communication signal transmitted to the roadside communication device 608B using the FM RTT.

α6 is an angle of arrival and/or angle of departure estimate obtained by the in-vehicle communication device 620 using a communication device multiple-input multiple-output (MIMO) antenna structure and communication signals transmitted to the wayside communication device 608B.

The accuracy of the train location obtained using the communication infrastructure varies depending on the actual capabilities and features of the communication system. However, this estimate is used as an input to a fusion algorithm in which radar 622 is focused on a designated area identified by in-vehicle communication device 620 and roadside communication device 608. Radar 622 extracts measurements from the target represented by the reflector array associated with wayside communication device 608A.

R7 and α7 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 1A in the reflector array associated with wayside communication device 608A on the a-side.

R8 and α8 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 2A in the reflector array associated with wayside communication device 608A on the a-side.

R9 and α9 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 3A in the reflector array associated with wayside communication device 608A on the a-side.

R10 and α10 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 1B in the reflector array associated with roadside communication device 608B on the B side.

R11 and α11 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 2B in the reflector array associated with roadside communication device 608B on the B side.

R12 and α12 are the distance of arrival and angle measured by radar 622, which transmits radar signals to and receives return signals from reflector 3B in the reflector array associated with roadside communication device 608B on the B side.

In some embodiments, the distance measurements R1, R2, R4, R5, R7, R8, R9, R10, R11, R12 and the angle of arrival and/or angle of departure measurements α3, α6, α7, α8, α9, α10, α11, α12 are all transmitted to a computer device, such as computer device 124 in fig. 1B. The computer device 124 is configured to implement a fusion algorithm having as inputs the distance measurements R1, R2, R4, R5, R7, R8, R9, R10, R11, R12 and the angle of arrival and/or departure measurements α3, α6, α7, α8, α9, α10, α11, α12 and to output a high integrity position estimate for the vehicle 102. Each of the distance measurements R1, R2, R4, R5, R7, R8, R9, R10, R11, R12, and the angle of arrival and/or angle of departure measurements α3, α6, α7, α8, α9, α10, α11, α12 increase the accuracy of locating the vehicle 102. Examples of fusion algorithms are discussed in U.S. patent application Ser. No. 16/714,175, filed on 12 months 13 in 2019, and U.S. patent application Ser. No. 17/115,348, filed on 8 months 12 in 2020, both of which are incorporated herein by reference in their entireties.

Fig. 7 is a top view of a high integrity vehicle positioning system 700, according to some embodiments.

The high integrity vehicle positioning system 700 in fig. 7 is identical to the high integrity vehicle positioning system 600 in fig. 6, except that the reflector 1A, reflector 2A, and reflector 3A on the a-side do not have the same configuration as the reflector 1B, reflector 2B, and reflector 3B on the B-side.

The reflector 1A, the reflector 2A, and the reflector 3A on the a side are aligned with respect to the Y axis and offset with respect to the X axis. In addition, the reflector 1B, the reflector 2B, and the reflector 3B on the B side are aligned with respect to the Y axis and offset with respect to the X axis. However, the reflector 1A, the reflector 2A, and the reflector 3A on the a side are spaced farther apart with respect to the X axis than the reflector 1B, the reflector 2B, and the reflector 3B on the B side.

In some embodiments, the distance measurements R1, R2, R4, R5, R7, R8, R9, R10, R11, R12 and the angle of arrival and/or departure measurements α3, α6, α7, α8, α9, α10, α11, α12 are made by the high integrity vehicle positioning system 700 in the same manner as discussed above with respect to the high integrity vehicle positioning system 600 in fig. 6.

Fig. 8 is a top view of a high integrity vehicle positioning system 800, according to some embodiments.

The high integrity vehicle positioning system 800 in fig. 8 is identical to the high integrity vehicle positioning system 600 in fig. 6, except that the reflector 1A, reflector 2A, and reflector 3A on the a-side do not have the same configuration as the reflector 1B, reflector 2B, and reflector 3B on the B-side.

The reflector 1A, the reflector 2A, and the reflector 3A on the a side are aligned with respect to the X axis and offset with respect to the Y axis. In addition, the reflector 1B, the reflector 2B, and the reflector 3B on the B side are aligned with respect to the Y axis and offset with respect to the X axis.

In some embodiments, the distance measurements R1, R2R4, R5, R7, R8, R9, R10, R11, R12 and the angle of arrival and/or departure measurements α3, α6, α7, α8, α9, α10, α11, α12 are made by the high integrity vehicle positioning system 800 in the same manner as discussed above with respect to the high integrity vehicle positioning system 600 in fig. 6.

Fig. 9 is a top view of a high integrity vehicle positioning system 900, according to some embodiments.

The high integrity vehicle positioning system 900 in fig. 9 is identical to the high integrity vehicle positioning system 600 in fig. 6, except that the reflector 1A, reflector 2A, and reflector 3A on the a-side do not have the same configuration as the reflector 1B, reflector 2B, and reflector 3B on the B-side.

The reflector 1A, the reflector 2A, and the reflector 3A on the a side are aligned with respect to the X axis and offset with respect to the Y axis. In addition, the reflector 1B, the reflector 2B, and the reflector 3B on the B side are aligned with respect to the Y axis and offset with respect to the X axis. Thus, the high integrity vehicle positioning system 900 is similar to the high integrity vehicle positioning system 800 in fig. 8, except that reflector 1A, reflector 2A, and reflector 3A are closer to the roadside communication device 608A on the a side and reflector 1B, reflector 2B, and reflector 3B are closer to the roadside communication device 608B on the B side.

In some embodiments, the distance measurements R1, R2, R4, R5, R7, R8, R9, R10, R11, R12 and the angle of arrival and/or departure measurements α3, α6, α7, α8, α9, α10, α11, α12 are made by the high integrity vehicle positioning system 900 in the same manner as discussed above with respect to the high integrity vehicle positioning system 600 in fig. 6.

Fig. 10 is a side view of a high integrity vehicle positioning system 1000, according to some embodiments.

The high integrity vehicle positioning system 1000 in fig. 10 is the same as the high integrity vehicle positioning system 600 in fig. 6, except for the configuration of the reflectors 1A, 2A and 3A on the a-side and the reflectors 1B, 2B and 3B on the B-side.

The reflector 1A, the reflector 2A, and the reflector 3A on the a side are offset with respect to the X axis and the Z axis. The Z axis is perpendicular relative to both the X axis and the Y axis. The reflector 1A is the most distant left side with respect to the X axis and the highest with respect to the Z axis. The reflector 3A is the most distant on the a-side with respect to the right side of the X-axis and the lowest with respect to the Z-axis. The reflector 2A is a reflector on the a side between the reflector 1A with respect to the X axis and with respect to the Z axis.

The reflector 3B is the reflector on the side B furthest to the left with respect to the X axis and highest with respect to the Z axis. The reflector 1B is the reflector on the B side, furthest to the right with respect to the X axis, and lowest with respect to the Z axis. The reflector 2B is a reflector on the B side between the reflector 1 with respect to the X axis and with respect to the Z axis.

The reflector 3B on the B side is higher than the reflector 1A on the a side, but the reflector 1A on the a side is higher than the reflector 2B on the B side. The reflector 2B on the B side is higher than the reflector 2B on the a side, but the reflector 2A on the a side is higher than the reflector 1A on the B side. The reflector 3B on the B side is higher than the reflector 1A on the B side. The reflector 1B, the reflector 2B, and the reflector 3B on the B side are all closer to the right side of the page than the reflector 1A, the reflector 2A, and the reflector 3A on the a side with respect to the X axis.

The change in the heights of reflector 1A, reflector 2A, and reflector 3A on side a and reflector 1B, reflector 2B, and reflector 3B on side B results in the reflection of radar signals from radar 622 with unique radar signatures that allow identification of location 607 based on the unique signatures. In some embodiments, the unique radar signature is the amplitude and/or phase of a reflected radar signal having a unique and identifiable pattern with respect to the frequency and/or time domain. In some embodiments, the unique radar signals have unique return angles and/or return elevation angles.

Fig. 11 is a side view of a high integrity vehicle positioning system 1100, according to some embodiments.

The high integrity vehicle positioning system 1100 in fig. 11 is the same as the high integrity vehicle positioning system 600 in fig. 6, except for the configuration of the reflectors 1A, 2A and 3A on the a-side and the reflectors 1B, 2B and 3B on the B-side.

The reflector 1A, the reflector 2A, and the reflector 3A on the a side are offset with respect to the X axis and the Z axis. The reflector 1A is the furthest reflector on the left side of the page with respect to the X axis and the highest reflector on the page with respect to the Z axis. The reflector 3A is the reflector furthest on the right side of the page with respect to the X-axis and on the lowest a-side with respect to the Z-axis. The reflector 2A is a reflector on the a side between the reflectors 1A with respect to the X axis and with respect to the Z axis.

The reflector 1A on the a side has a larger RCS than the reflector 2A and the reflector 3A on the a side. The reflector 2A on the a-side has a larger RCS than the reflector 3A on the a-side.

The reflector 3B is the reflector on the B side furthest to the left of the page with respect to the X axis and highest in height with respect to the Z axis. The reflector 1B is the most distant on the right side with respect to the X axis and the lowest on the B side with respect to the Z axis. The reflectors 2B are reflectors on the B side between the reflectors 1B with respect to the X axis and with respect to the Z axis.

The reflector 3B on the B side has a larger RCS than the reflector 1A and the reflector 2A on the a side. The reflector 2A on the a-side has a larger RCS than the reflector 1A on the a-side.

The reflector 3B on the B side is higher than the reflector 1A on the a side, but the reflector 1A on the a side is higher in height than the reflector 2B on the B side. The reflector 2 on the B side is higher than the reflector 2 on the a side, but the reflector 2 on the a side is higher than the reflector 1 on the B side. The reflector 3B on the B side is higher than the reflector 1B on the B side. The reflector 1B, the reflector 2B, and the reflector 3B on the B side are all closer to the right side of the page than the reflector 1A, the reflector 2A, and the reflector 3A on the a side with respect to the X axis.

The reflector 1A on the a side has the same RCS as the reflector 3B on the B side. The reflector 2A on the a side has the same RCS as the reflector 2B on the B side. The reflector 3A on the a side has the same RCS as the reflector 1B on the B side. In other embodiments, reflector 1A on side a has a different RCS than reflector 3B on side B. In other embodiments, the reflector 2A on the a-side has a different RCS than the reflector 2B on the B-side. In other embodiments, reflector 3A on side a has a different RCS than reflector 1B on side B.

The height of reflector 1A, reflector 2A and reflector 3A on RCS and a side and reflector 1B, reflector 2B and reflector 3B on B side varies to reflect radar signals from radar 622 with unique radar signatures that allow for identification of location 607 based on the unique signatures. In some embodiments, the unique radar signature is the amplitude and/or phase of a reflected radar signal having a unique and identifiable pattern with respect to the frequency and/or time domain. In some embodiments, the unique radar signals have unique return angles and/or return elevation angles.

Fig. 12 is a top view of an antenna 1202 of a wayside communication device and a reflector 1204 that at least partially encapsulates the antenna 1202, according to some embodiments.

In some embodiments, the antenna 1202 corresponds to the antenna 220 of the wayside communication device 200 in fig. 2. Reflector 1204 corresponds to reflector 110 in fig. 1A at a particular location 107.

In this embodiment, the reflector 1204 is a radome that at least partially encapsulates the antenna 1202. The reflector 1204 is transparent (transparent) to the communication signal from the in-vehicle communication device 120 (see fig. 1B), and reflects the radar signal from the radar system 122 (see fig. 1B). In some embodiments, the communication signal is transmitted to an antenna 1202 (see fig. 1A) on the wayside communication device 108. The antenna is at least partially encapsulated by a reflector 1204. The reflector 1204 is transparent to the baseband frequency of the communication signal. In some embodiments, the baseband frequency of the communication signal is between 2.4GHz and 10 GHz. The vehicle positioning estimation is obtained by the in-vehicle communication device 120 based on the communication signal as described above. In some embodiments, reflector 1204 completely encapsulates antenna 1202.

Radar signals are transmitted by radar system 122 (see fig. 1B) to wayside communication device 108 (see fig. 1A). Reflector 1204 is a retroreflection of the baseband frequency of the radar signal. In some embodiments, computer device 124 (see FIG. 1B) receives measurements from in-vehicle communication device 120 (see FIG. 1B) and/or radar system 122 (see FIG. 1B) and improves the accuracy of the vehicle location estimate based on radar signal returns. In some embodiments, the baseband frequency of radar system 122 (see FIG. 1B) is between 76GHz and 81 GHz. The baseband frequency of the communication signal between 2.4GHz and 10GHz and the baseband frequency of the radar system 122 between 76GHz and 81GHz provide a "wide" gap between the two baseband frequencies.

In some embodiments, the reflector 1204 is composed of a Frequency Selective Surface (FSS) metamaterial. The FSS material is transparent to the baseband frequency of the communication signal and retroreflective at the baseband frequency of the radar signal.

In some embodiments, the range and AoA/AoD estimates of the communication signals are input into a radar target selection algorithm (beam steering and range gating unit). Based on the distance from the communication signal and the AoA/AoD estimate, a location window of the radar signal is initially selected to more accurately obtain a location of the vehicle 102 (see fig. 1A).

Fig. 13 is a graph of distance accuracy for the maximum distance for each distance measurement technique, according to some embodiments.

The center of the distance map represents the positioning of the antennas of the roadside communication device.

Distance 1302 has acceptable distance accuracy beyond distance 1302, but is least accurate in distance measurement techniques. When estimating the distance to the antenna at the center using RSSI techniques, distance 1302 indicates that the distance accuracy remains acceptable outside of distance 1302.

Distance 1304 has a distance accuracy that remains acceptable for distance 1304, where distance 1304 is smaller than distance 1302 but has a higher accuracy than RSSI techniques. When the range to the antenna is estimated using FM RTT distance measurement techniques, distance 1304 indicates that the accuracy of the distance outside of distance 1304 remains acceptable.

Distance 1306 has a distance accuracy that remains acceptable for distance 1306, where distance 1306 is similar to distance 1304 in that the accuracy of distance 1306 is still determined by the FM RTT technique. The distance 1306 to the antenna is increased by angle of arrival and/or angle of departure measurements, which enables locating the vehicle with a single distance and a single AoA/AoD.

Distance 1308 has a distance accuracy that remains acceptable for distance 1308, where distance 1308 is less than distance 1306 but more accurate than measuring distance using FM RTT. When estimating the distance to the antenna using radar signals, distance 1308 represents that the distance accuracy of distance 1308 remains outside of acceptable distance 1308. The distance 1308 to the antenna is increased by the angle of arrival and/or angle of departure measurements, which enables locating the vehicle with a single distance and a single AoA/AoD.

The distances 1302, 1304, 1306, 1308 are for illustrative purposes only and are not drawn to scale.

Fig. 14A is a flow 1400 of a method of positioning a rail mounted vehicle, according to some embodiments.

The rail mounted vehicle corresponds to the vehicle 102 in fig. 1A and 6-11. Flow begins at block 1402.

At block 1402, a communication signal is transmitted to a wayside communication device. In some embodiments, block 1402 is performed by an in-vehicle communication device, such as in-vehicle communication device 120 in fig. 1B, in-vehicle communication device 300 in fig. 3, and in-vehicle communication device 620 in fig. 6-11. The communication signal corresponds to communication signal 352 in fig. 3. The wayside communication device corresponds to the wayside communication device 108 in fig. 1A, the wayside communication device 200 in fig. 2 and the wayside communication device 608 in fig. 6-11. Flow then proceeds to block 1404.

At block 1404, a vehicle positioning estimate is obtained based on the communication signal. In some embodiments, computer device 124 in fig. 1B is configured to perform block 1404. Flow then proceeds to block 1406.

At block 1406, the radar signal is transmitted to at least one reflector. In some embodiments, block 1406 is performed by radar system 122 in fig. 1B, radar system 500 in fig. 5, and radar 622 in fig. 6-11. The radar signal corresponds to radar signal 550 in fig. 5. At least one reflector corresponds to reflector 110 in fig. 1A, reflector 2A and reflector 3A on the a side of fig. 6-11, reflector 1B, reflector 2B, reflector 3B on the B side of fig. 6-11, and reflector 1204 of fig. 12. Flow then proceeds to block 1408.

At block 1408, accuracy of the vehicle location estimate is increased based on the radar signal. In some embodiments, block 1408 is performed by computer device 124 in fig. 1B. The radar signal corresponds to radar signal 550 in fig. 5.

Fig. 14B is a flow 1410 of a method of positioning a rail mounted vehicle, according to some embodiments.

The rail mounted vehicle corresponds to the vehicle 102 in fig. 1A and 6-11. Flow begins at block 1412.

At block 1412, the communication signal is transmitted to the in-vehicle communication device. In some embodiments, block 1412 is performed by a wayside communication device, such as wayside communication device 108 in fig. 1A, wayside communication device 200 in fig. 2, and wayside communication device 608 in fig. 6-11. The communication signal corresponds to communication signal 252 in fig. 2. The in-vehicle communication device corresponds to the communication device 108 in fig. 1A, the roadside communication device 200 in fig. 2, and the roadside communication device 608 in fig. 6-11. Flow then proceeds to block 1404.

At block 1414, a vehicle location estimate is obtained based on the communication signal. In some embodiments, computer device 124 in fig. 1B is configured to perform block 1414. Flow then proceeds to block 1416.

At block 1416, the radar signal is transmitted to at least one reflector. In some embodiments, block 1416 is performed by radar system 122 in fig. 1B, radar system 500 in fig. 5, and radar 622 in fig. 6-11. The radar signal corresponds to radar signal 550 in fig. 5. At least one reflector corresponds to reflector 110 in fig. 1A, reflector 2A and reflector 3A on the a side of fig. 6-11, reflector 1B, reflector 2B, reflector 3B on the B side of fig. 6-11, and reflector 1204 of fig. 12. Flow then proceeds to block 1418.

At block 1418, accuracy of the vehicle location estimate is improved based on the radar signal. In some embodiments, block 1418 is performed by computer device 124 in fig. 1B. The radar signal corresponds to radar signal 550 in fig. 5. .

Fig. 15A is a flow 1500 of a method of obtaining a range estimate based on a communication signal, according to some embodiments.

According to some embodiments, flow 1500 corresponds to block 1404 in fig. 14A. Flow begins at block 1502.

At block 1502, a range distance estimate is obtained based on a correlation between the distance and the signal-to-noise ratio. In some embodiments, the correlation of the signal-to-noise ratio with the range distance estimate is an RSSI estimate, where the signal-to-noise ratio distribution is based on a poisson distribution. It should be noted that block 1502 is performed several times, for example when a plurality of wayside communication devices are in a particular location, for example the examples in fig. 6-11 have a wayside communication device 608A and a wayside communication device 608B. Flow then proceeds to block 1504.

At block 1504, a time of flight of the RF signal from the in-vehicle communication device to the wayside communication device and back to the in-vehicle communication device is measured. In some embodiments, block 1504 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). In some embodiments, the RF signal is a communication signal. Flow then proceeds to block 1506.

At block 1506, a measurement distance is determined based on the time of flight. In some embodiments, block 1506 is performed multiple times, such as when block 1504 is performed multiple times. Flow then proceeds to block 1508.

At block 1508, the angle of departure of the RF signal from the in-vehicle communication device to the wayside communication device is measured. In some embodiments, block 1508 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). Flow then proceeds to block 1510.

At block 1510, an angle of arrival of a second RF signal from the wayside communication device to the in-vehicle communication device is measured. In some embodiments, block 1508 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). In some embodiments, the second RF signal is a second communication signal. Flow then proceeds to block 1512.

At block 1512, an angle of arrival and/or angle of departure between the in-vehicle communication device and the wayside communication device is determined based on the angle of departure and/or angle of arrival. In some embodiments, block 1512 is performed multiple times, such as when blocks 1508 and 1510 are performed multiple times.

In FIG. 15A, all blocks 1502-1512 are performed. In some embodiments, all angles of arrival and/or angles of departure from these boxes are input into a fusion algorithm to obtain a position estimate. In some embodiments, only block 1502 is performed, and blocks 1504-1512 are not performed (block 1502 is referred to as subset 1 of the blocks). In some embodiments, only blocks 1504 and 1506 are performed, and blocks 1502 and 1508-1512 are not performed (the combination of block 1504 and block 1506 is referred to as subset 2 of blocks). In some embodiments, only blocks 1508 and 1512 are performed, and blocks 1502-1506 and 1510 are not performed (the combination of blocks 1508 and 1512 is referred to as subset 3 of blocks). In some embodiments, only blocks 1510 and 1512 are performed, but blocks 1502-1506 and 1508 are not performed (the combination of block 1510 and block 1512 is referred to as subset 4 of blocks). In some embodiments, only blocks 1508, 1510, and 1512 are performed, but blocks 1502-1506 are not performed (the combination of blocks 1508, 1510, and 1512 is referred to as subset 5 of blocks). In some embodiments, more than one of the subsets of boxes 1, 2, 3, 4, 5 is performed, but not all of the subsets of boxes 1, 2, 3, 4, 5.

Fig. 15B is a flow 1520 of a method of obtaining a range estimate based on a communication signal, in accordance with some embodiments.

According to some embodiments, flow 1520 corresponds to block 1414 in fig. 14B. Flow begins at block 1522.

At block 1522, a distance estimate is obtained based on the correlation between the range distance and the signal-to-noise ratio. In some embodiments, the correlation of the signal-to-noise ratio with the range distance estimate is an RSSI estimate, where the signal-to-noise ratio distribution is based on a poisson distribution. It should be noted that block 1522 is performed several times, such as when there are multiple in-vehicle communicators on a guideway-mounted vehicle, such as the example shown in fig. 1A with in-vehicle communicators 120. Flow then proceeds to block 1524.

At block 1524, the time of flight of the RF signal from the wayside communication device to the in-vehicle communication device and back to the wayside communication device is measured. In some embodiments, block 1524 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). In some embodiments, the RF signal is a communication signal. Flow then proceeds to block 1526.

At block 1526, a measurement distance is determined based on the time of flight. In some embodiments, block 1526 is performed multiple times, such as when block 1524 is performed multiple times. Flow then proceeds to block 1528.

At block 1528, the angle of departure of the RF signal from the wayside communication device to the in-vehicle communication device is measured. In some embodiments, block 1528 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). Flow then proceeds to block 1530.

At block 1530, an angle of arrival of a second RF signal from the in-vehicle communication device to the wayside communication device is measured. In some embodiments, block 1528 is performed multiple times, such as when there are multiple in-vehicle communication devices (see in-vehicle communication device 120 in fig. 1A) and/or multiple roadside communication devices (see roadside communication device 608A and roadside communication device 608B in fig. 6-11). In some embodiments, the second RF signal is a second communication signal. Flow then proceeds to block 1532.

At block 1532, an angle of arrival and/or angle of departure between the in-vehicle communication device and the wayside communication device is determined based on the angle of departure and/or angle of arrival. In some embodiments, block 1532 is performed multiple times, such as when blocks 1528 and 1530 are performed multiple times.

In FIG. 15B, all of the modules 1522-1532 are executed. In some embodiments, all angles of arrival and/or angles of departure from these boxes are input into a fusion algorithm to obtain a position estimate. In some embodiments, only block 1522 is performed, and blocks 1524-1532 are not performed (block 1522 is referred to as subset 1 of the blocks). In some embodiments, only blocks 1524 and 1526 are performed, and blocks 1522 and 1528-1532 are not performed (the combination of block 1524 and block 1526 is referred to as a subset 2 of blocks). In some embodiments, only blocks 1528 and 1532 are performed, and blocks 1522-1526 and 1530 are not performed (the combination of block 1528 and block 1532 is referred to as subset 3 of blocks). In some embodiments, only blocks 1530 and 1532 are performed, and blocks 1522-1526 and 1528 are not performed (the combination of block 1530 and block 1532 is referred to as subset 4 of blocks). In some embodiments, only blocks 1528, 1530, and 1532 are performed, and blocks 1522-1526 are not performed (the combination of blocks 1528, 1530, and 1532 is referred to as a subset of blocks 5). In some embodiments, more than one of the subsets of boxes 1, 2, 3, 4, 5 is performed, but not all of the subsets of boxes 1, 2, 3, 4, 5.

Fig. 16A is a flow 1600 of a method of improving accuracy of a vehicle location estimate based on radar signals, according to some embodiments.

According to some embodiments, flow 1600 corresponds to block 1408 in fig. 14A.

At block 1602, a time of flight of the radar signal from the in-vehicle radar system to the reflector and back to the in-vehicle radar system is measured. In some embodiments, block 1602 is performed multiple times, such as when multiple radar systems are present, such as radar system 122 in fig. 1B. Flow then proceeds to block 1604.

At block 1604, an angle of arrival of a radar signal returned from the first reflector to the in-vehicle radar system is measured. Flow then proceeds to block 1606.

At block 1606, an angle of departure of the radar signal traveling from the in-vehicle radar system to the first reflector is measured.

In some embodiments, at block 1604, an angle of arrival is measured from a radar signal that is returned from a first reflector to a wayside radar system. Flow then proceeds to block 1606.

At block 1606, an angle of departure for the radar signal traveling from the wayside radar system to the first reflector is measured.

Fig. 16B is a flow 1610 of a method of improving accuracy of a vehicle location estimate based on radar signals, according to some embodiments.

According to some embodiments, flow 1610 corresponds to block 1418 in fig. 14B.

At block 1612, a time of flight of the radar signal from the wayside radar system to at least one reflective surface of the rail mounted vehicle and back to the wayside radar system is measured. In some embodiments, block 1612 is performed multiple times, such as when multiple radar systems are present at a wayside location. Flow then proceeds to block 1614.

At block 1614, an angle of arrival of a radar signal that is returned from the at least one reflective surface to the wayside radar system is measured. Flow then proceeds to block 1616.

At block 1616, an angle of departure of the radar signal traveling from the wayside radar system to the at least one reflective surface is measured.

In some embodiments, at block 1614, an angle of arrival is measured for radar signals that are returned from at least one reflective surface to the wayside radar system. Flow then proceeds to block 1616.

Fig. 17A is a flow 1700 of a method of positioning a rail mounted vehicle, according to some embodiments.

Flow 1700 includes blocks 1702-1706. According to some embodiments, block 1702 corresponds to block 1406 in fig. 14A. According to some embodiments, blocks 1704 and 1706 correspond to block 1408 of fig. 14A.

At block 1702, a radar signal is transmitted to a reflector array. Exemplary reflector arrays include the reflector 1A shown in fig. 6-11, reflector 3A on the side of reflector 2A, A and reflector 1B, reflector 3B on the side of reflector 2B, B. Flow then proceeds to block 1704.

At block 1704, time of flight to the reflector array is measured, where each time of flight is a time of flight corresponding to a different reflector in the reflector array. Flow then proceeds to block 1706.

At block 1706, angles of arrival and departure of the reflector array are measured, where each of the angles of arrival and departure are angles corresponding to different reflectors in the reflector array. Flow then proceeds to block 1708.

At block 1708, a fusion algorithm is performed that calculates an estimated location of the rail mounted vehicle based on the measured time-of-flight distance estimate, the angle of arrival estimate, and the angle of departure estimate. The distance estimate corresponds to the distance estimate determined at 1404 of fig. 14A. In fig. 17A, a single radar signal is used to determine all times of flight to each reflector. The angle of arrival and angle of departure estimates correspond to the angle of arrival and angle of departure estimates determined at 1408 of fig. 14A. In fig. 17A, radar signals are used to determine the time of flight, angle of arrival, and angle of departure for each reflector.

Fig. 17B is a flow 1710 of a method of positioning a rail mounted vehicle, according to some embodiments.

Flow 1710 includes blocks 1712-1716. According to some embodiments, block 1712 corresponds to block 1416 in fig. 14B. Blocks 1714 and 1716 correspond to block 1418 in fig. 14B, according to some embodiments.

At block 1712, the radar signal is transmitted to at least one reflective surface of the rail mounted vehicle. Flow then proceeds to block 1714.

At block 1714, a time of flight of the at least one reflective surface is measured. Flow then proceeds to block 1716.

At block 1716, angles of arrival and angles of departure are measured relative to the at least one reflective surface, where each of the angles of arrival and angles of departure are angles corresponding to different reflectors in the at least one reflective surface. Flow then proceeds to block 1718.

At block 1718, a fusion algorithm is performed that calculates an estimated location of the rail mounted vehicle based on the measured time-of-flight distance estimates, the angle of arrival estimates, and the angle of departure estimates.

Fig. 18 is a flow 1800 of a method of locating a guideway-mounted vehicle according to some embodiments.

Flow 1800 includes blocks 1802 and 1810. According to some embodiments, block 1802 corresponds to block 1406 of fig. 14. Blocks 1806-1810 correspond to block 1408 in fig. 14, according to some embodiments.

At block 1802, a radar signal is transmitted to a first reflector. Exemplary first reflectors include reflector 1A, reflector 2A, reflector 3A and reflector 1B, reflector 2B, reflector 3B on side a shown in fig. 6-11. An exemplary radar signal is radar signal 550 in fig. 5. In some embodiments, the radar system that generates the radar signal is on in the vehicle and is an on-board radar system, and in some embodiments, the radar system is on the road side of the guideway and is a roadside radar system. Flow then proceeds to block 1804.

At block 1804, a second radar signal is transmitted to a second reflector. Exemplary first reflectors include reflector 1A, reflector 2A, reflector 3A and reflector 1B, reflector 2B, reflector 3B on side a shown in fig. 6-11. An exemplary second radar signal is radar signal 550 in fig. 5. Flow then proceeds to block 1806.

At block 1806, a first time of flight of the radar signal to the first reflector is measured. Flow then proceeds to block 1807.

At block 1807, a first angle of arrival of the radar signal from the first reflector is measured. Flow then proceeds to block 1808.

At block 1808, a first angle of departure of the radar signal to the first reflector is measured. Flow then proceeds to block 1809.

At block 1809, a second time of flight of the second radar signal to a second reflector is measured. Flow then proceeds to block 1810.

At block 1810, a second angle of arrival of the radar signal from the second reflector is measured. Flow then proceeds to block 1811.

At block 1811, a second angle of departure of the radar signal to the first reflector is measured. Flow then proceeds to block 1812.

At block 1812, a fusion algorithm is performed that calculates an estimated location of the rail mounted vehicle based on the first time of flight (distance estimate to the first reflector), the first angle of arrival (from the first reflector), the first departure angle (to the first reflector), the second time of flight (distance estimate to the second reflector), the second angle of arrival (from the second reflector), and the second departure angle (to the second reflector). The distance estimate corresponds to the distance estimate determined in block 1404 in fig. 14. Note that in some embodiments, more than two radar signals are transmitted to measure more than two times of flight, more than two angles of arrival, and more than two angles of departure. In some embodiments, these additional radar signals are transmitted to an additional radar reflector, such as a third radar reflector. These additional time of flight, angle of arrival and angle of departure are also input into the fusion algorithm to increase the accuracy of the estimated location of the guideway-mounted vehicle.

Fig. 19 is a flow 1900 of a method of increasing accuracy of a range estimation based on a radar signal, according to some embodiments.

According to some embodiments, flow 1900 corresponds to block 1408 in fig. 14. Flow 1900 includes blocks 1902 and 1908. Flow begins at block 1902.

At block 1902, a roadside communication device is identified based on the unique ID and a location of the roadside communication device is determined based on the map and the database. Flow then proceeds to block 1904.

At block 1904, the reflected radar signal is detected based on a detection window triggered by roadside device detection. Flow then proceeds to block 1906. In some embodiments, the reflector array is placed in a particular location having reflectors arranged to reflect radar signals such that the reflected radar signals have unique radar signatures.

At block 1906, unique radar signatures of the reflected radar signals are detected. In some embodiments, the unique radar signature is a unique signature of the reflector array. Flow then proceeds to block 1908.

At block 1908, a stored position of the identified one or more reflectors is obtained based on the unique radar signature and the association with the position. In some embodiments, the digital version of the unique tag is transmitted to a server to find a match in a database. Once a match is found, reflector positioning data associated with the identified wayside communication device is obtained to identify the positioning of the reflector. In this way, a reflector array or other reflective object with unique radar signatures is used to correlate the positioning of the reflector or reflector array with the positioning of the wayside communication device.

Fig. 20 is a flow 2000 of a method of locating a rail mounted vehicle, according to some embodiments.

The rail mounted vehicle corresponds to the vehicle 102 in fig. 1A and 6-11. Flow begins at block 2002.

At block 2002, the communication signal is transmitted to an antenna on the wayside communication device, wherein the antenna is at least partially encapsulated by a radome transparent to baseband frequencies of the communication signal. In some embodiments, block 2002 is performed by an in-vehicle communication device, such as in-vehicle communication device 120 in fig. 1B, in-vehicle communication device 300 in fig. 3, and in-vehicle communication device 620 in fig. 6-11. The communication signal corresponds to communication signal 352 in fig. 3. The wayside communication device corresponds to the wayside communication device 108 in fig. 1A, the wayside communication device 200 in fig. 2, and the wayside communication device 608 in fig. 6-11. In some embodiments, the antennas of the wayside communication device correspond to antennas 1202 in fig. 12. In some embodiments, the radome corresponds to reflector 1204 in fig. 12. In some embodiments, the baseband frequency of the communication signal is between 2.4GHz and 10 GHz. Flow then proceeds to block 1404.

At block 2004, a range estimate is obtained based on the communication signal. In some embodiments, computer device 124 in fig. 1B is configured to perform block 2004. Flow then proceeds to block 2005.

At block 2005, an angle of arrival and an angle of departure are obtained based on the communication signal. Flow then proceeds to block 2006.

At block 2006, the radar signal is transmitted to a wayside communication device, wherein the radome is back-reflected to baseband frequencies of the radar signal. In some embodiments, block 2006 is performed by radar system 122 in fig. 1B, radar system 500 in fig. 5, and radar 622 in fig. 6-11. The radar signal corresponds to radar signal 550 in fig. 5. In some embodiments, the baseband frequency of the radar signal is between 76GHz and 81 GHz. Flow then proceeds to block 2007.

At block 2007, a second range estimate, a second angle of arrival, and a second angle of departure are obtained based on the radar signal. Flow then proceeds to block 2008.

At block 2008, accuracy of the positioning estimate is improved based on the radar signal range, aoA, and AoD estimates. In some embodiments, block 1408 is performed by computer device 124 in fig. 1B.

Fig. 21 is a flow 2100 of a method of locating a rail mounted vehicle, according to some embodiments.

Flow 2100 includes blocks 2102-2118. Flow begins at block 2102.

At block 2102, a first communication signal is transmitted from an in-vehicle communication device to a wayside communication device. Flow then proceeds to block 2104.

At block 2104, a second communication signal is transmitted from the wayside communication device to the in-vehicle communication device. Flow then proceeds to block 2106.

At block 2106, a first radar signal is transmitted from the in-vehicle radar system to at least one reflector. Flow then proceeds to block 2108.

At block 2108, a second radar signal is transmitted from the wayside radar system to at least one reflective surface of the rail mounted vehicle. Flow then proceeds to block 2110.

At block 2110, a first vehicle location estimate is obtained based on the first communication signal. Flow then proceeds to block 2112.

At block 2112, a second vehicle location estimate is obtained based on the second communication signal. Flow then proceeds to block 2114.

At block 2114, a third vehicle location estimate is obtained based on the first radar signal. Flow then proceeds to block 2116.

At block 2116, a fourth vehicle positioning estimate is obtained based on the second radar signal. Flow then proceeds to block 2118.

At block 2118, the first, second, third, and fourth vehicle location estimates are compared to determine if the difference between the first, second, third, and fourth vehicle location estimates is within an error range.

Fig. 22 is a flow 2200 of a method for locating a rail mounted vehicle, according to some embodiments.

Flow 2200 includes blocks 2202-2206. Flow begins at block 2202.

At block 2202, a radar signal is transmitted from an in-vehicle radar device to at least one reflector. Flow then proceeds to block 2204.

At block 2204, a vehicle location estimate is obtained based on the radar signals. In some embodiments, the high safety integrity vehicle location estimate of the guideway-mounted vehicle is determined by using the distance estimate, the AoD of the radar signal, and the AoA of the reflected radar signal. The positioning of the reflectors is known and identified by a unique ID or based on unique radar signatures. The location of the reflector is obtained from a database using the unique ID and/or unique radar signature. Flow then proceeds to block 2204.

At block 2206, a vehicle speed estimate is measured based on the radar signal. In some embodiments, one of the advantages of using a reflector is that the reflector is stationary. Thus, the measured relative radial velocity represents the ground velocity component along the line of sight (LOS) from the radar to the reflector. The transformation is calculated taking into account azimuth and elevation. The reflector eliminates the risk that the relative radial velocity measured by the radar is measured relative to a non-stationary target. In some embodiments, doppler (Doppler) Frequency Modulated Continuous Wave (FMCW) technology is used to measure the distance to an object in the field of view (FOV), the angular position of the object in the FOV, and the radial relative velocity between the radar and the object. In some embodiments, non-Doppler FMCW techniques are used to measure the distance to the object in the FOV, the angular position of the object in the FOV, and the radial relative velocity between the radar and the object.

In some embodiments, a method of positioning a guideway-mounted vehicle, the method comprising: transmitting the communication signal to a wayside communication device; obtaining a range estimate based on the communication signal; transmitting radar signals to at least one reflector; and improving accuracy of the range estimation based on the radar signal. In some embodiments, obtaining the distance estimate based on the communication signal includes obtaining a signal-to-noise ratio range distance correlation that correlates the distance estimate with a signal-to-noise ratio of the communication signal based on a signal-to-noise ratio distribution of the communication signal. In some embodiments, the at least one reflector comprises a reflector array having reflectors arranged to reflect radar signals such that the reflected radar signals have unique radar signatures, and wherein improving accuracy of the range estimation based on the radar signals comprises: detecting the reflected radar signal; identifying the unique radar signature of the reflected radar signal; associating the reflector with the wayside communication device based on the unique radar signature; and obtaining a stored position of at least one of the at least one reflector based on the unique radar signature and an association with the wayside communication device. In some embodiments, obtaining a range estimate based on the communication signal includes: measuring a time of flight of the communication signal transmitted from the on-board communication device to the wayside communication device and returned to the on-board communication device; and determining a measurement distance based on the time of flight. In some embodiments, the at least one reflector comprises a first reflector, and wherein improving the accuracy of the range estimation based on the radar signal comprises: the time of flight of the radar signal from an on-board radar system to the first reflector and back to the on-board radar system is measured, wherein the on-board radar system is on the guideway-mounted vehicle. In some embodiments, obtaining a range estimate based on the communication signal includes: measuring an angle of departure of the communication signal from an on-board communication device to the wayside communication device; measuring an angle of arrival of a second communication signal from the roadside communication device to the in-vehicle communication device; and determining a location of the guideway-mounted vehicle based on the distance estimate, the departure angle, and the arrival angle. In some embodiments, transmitting the communication signal to the wayside communication device comprises transmitting the communication signal to an antenna on the wayside communication device, wherein the antenna is at least partially enclosed by a radome transparent to baseband frequencies of the communication signal, wherein the at least one reflector comprises the radome; transmitting the radar signal to the at least one reflector comprises transmitting the radar signal to a radome of the roadside communication device, wherein the radome is retro-reflective to a baseband frequency of the radar signal. In some embodiments, the baseband frequency of the communication signal is between 2.4GHz to 10 GHz; the baseband frequency of the radar signal is between 76GHz and 81 GHz. In some embodiments, transmitting radar signals to at least one reflector includes transmitting radar signals to an array of reflectors; wherein improving accuracy of the range estimation based on the radar signals includes measuring time of flight to the reflector array, wherein each of the time of flight is a time of flight corresponding to a different reflector in the reflector array. In some embodiments, improving accuracy of the range estimation based on the radar signals further includes implementing a fusion algorithm that calculates an estimated location of the guideway-mounted vehicle based on the range estimation, the estimated departure angle, and the arrival angle. Transmitting the radar signal to the at least one reflector comprises transmitting the radar signal to a first reflector, and wherein the method further comprises transmitting a second radar signal to a second reflector. In some embodiments, improving accuracy of the distance estimation based on the radar signal includes implementing a fusion algorithm that calculates an estimated location of the guideway-mounted vehicle based on the distance estimation, the radar signal, and the second radar signal.

In some embodiments, an on-board communication system for a rail mounted vehicle includes: at least one wireless communication device; at least one radar device; a non-transitory computer readable medium configured to store computer executable instructions; and at least one processor operably associated with the at least one wireless communication device, the at least one radar device, and the non-transitory computer-readable medium, wherein the at least one processor, when executed by the at least one processor, is configured to: transmitting a communication signal from the at least one wireless communication device to a wayside communication device; obtaining a range estimate based on the communication signal; obtaining an angle of arrival and an angle of departure based on the communication signal transmitting radar signals from the at least one radar device to at least one reflector; obtaining a second angle of arrival and a second angle of departure based on the radar signal; and improving accuracy of the vehicle positioning estimation based on the radar signal. In some embodiments, to obtain a distance estimate based on the communication signal, the at least one processor is configured to obtain a signal-to-noise ratio range distance estimate that correlates the distance estimate to a signal-to-noise ratio of the communication signal based on a signal-to-noise ratio distribution of the communication signal. In some embodiments, the at least one reflector comprises a reflector array having reflectors arranged to reflect the radar signals such that the reflected radar signals have unique radar signatures, and wherein the at least one processor is configured to promote accuracy of the vehicle location estimate based on the radar signals by: detecting the reflected radar signal; identifying a unique radar signature of the reflected radar signal; associating the wayside communication device with the unique radar signature; and obtaining a stored position of at least one of the at least one reflector based on the unique radar signature. In some embodiments, the at least one processor is configured to promote accuracy of the vehicle location estimate based on the radar signals by: measuring a second angle of departure of the radar signal from a vehicle radar to a reflector, wherein the at least one radar device comprises the vehicle radar and the at least one reflector comprises the reflector; measuring a second angle of arrival of radar signals from the reflector to the vehicle radar; the position of the guideway-mounted vehicle is determined based on the angle of arrival of the second communication signal, the angle of departure of the second communication signal, and the distance estimate. In some embodiments, the at least one processor is configured to obtain the vehicle location estimate based on the communication signal by: measuring an angle of arrival of a second communication signal from the wayside communication device to the in-vehicle communication device; and measuring an angle of arrival of a second communication signal from the wayside communication device to the in-vehicle communication device; and determining a location of the guideway-mounted vehicle based on the angle of arrival, the angle of departure, and the distance estimate. In some embodiments: transmitting the communication signal to the wayside communication device comprising transmitting the communication signal to an antenna on the wayside communication device, wherein the antenna is at least partially enclosed by a radome transparent to baseband frequencies of the communication signal, wherein the at least one reflector comprises the radome; transmitting the radar signal to at least one reflector, comprising transmitting the radar signal to a radome of the wayside communication device, wherein the radome is retroreflective to baseband frequencies of the radar signal.

In some embodiments, a method of positioning a guideway-mounted vehicle, the method comprising: transmitting a communication signal to an antenna on a wayside communication device, wherein the antenna is at least partially enclosed by a radome, the radome being transparent to baseband frequencies of the communication signal; obtaining a range estimate based on the communication signal; transmitting radar signals to the wayside communication device, wherein the radome is retroreflective to baseband frequencies of the radar signals; and improving accuracy of the range estimation based on the radar signal. In some embodiments, obtaining the distance estimate based on the communication signal includes obtaining the distance estimate based on a signal-to-noise ratio distribution of the communication signal as a result of a distance between the wayside communication device and the in-vehicle communication device transmitting the communication signal.

In some embodiments, a method of positioning a guideway-mounted vehicle, the method comprising: transmitting communication signals between the vehicle-mounted communication device and the roadside communication device; obtaining a vehicle positioning estimate based on the communication signal; transmitting radar signals to at least one reflective surface; and improving accuracy of the vehicle positioning estimation based on the radar signal. In some embodiments, transmitting the communication signal between the in-vehicle communication device and the wayside communication device comprises: transmitting the communication signal from the in-vehicle communication device to the roadside communication device. In some embodiments, obtaining a vehicle location estimate based on the communication signal includes: receiving a second communication signal from the wayside communication device to the in-vehicle communication device in response to the communication signal transmitted from the in-vehicle communication device, wherein the second communication signal is modulated to include a unique identification of the wayside communication device; obtaining the unique identification of the wayside communication device from the second communication signal; obtaining positioning data identifying a wayside location of the wayside communication device based on the unique identification; and calculating the vehicle location estimate based on location data and at least one of the communication signals and the second communication signal. In some embodiments, transmitting the communication signal between the in-vehicle communication device and the wayside communication device comprises: transmitting the communication signal from the roadside communication device to the in-vehicle communication device. In some embodiments, the communication signal is modulated to include a unique identification of the wayside communication device, wherein obtaining the vehicle location estimate based on the communication signal comprises: obtaining a unique identification of the wayside communication device from the second communication signal; obtaining positioning data identifying a wayside location of the wayside communication device based on the unique identification; and transmitting a second communication signal from the in-vehicle communication device to the roadside communication device in response to the communication signal transmitted from the roadside communication device; the vehicle location estimate is calculated based on location data and at least one of the communication signals and the second communication signal. In some embodiments, the at least one reflective surface comprises at least one reflector alongside a roadway of the guideway, wherein transmitting the radar signal to the at least one reflective surface comprises: transmitting the radar signal from the vehicle radar system to the at least one reflector. In some embodiments, improving accuracy of vehicle location estimation based on radar signals includes detecting reflected radar signals; identifying a unique radar signature of the at least one reflector from the reflected radar signal; obtaining location data of the at least one reflector or the wayside communication device from a database based on the unique radar signature; and calculating a vehicle positioning estimate based on the radar signals and the positioning data. In some embodiments, the at least one reflector comprises at least one retroreflector alongside the rail. In some embodiments: the wayside communication device comprises one or more antennas; and the at least one retro-reflector includes a radome at least partially encapsulating the one or more antennas. In some embodiments, the at least one reflective surface comprises at least one rail-mounted vehicle surface, and wherein transmitting the radar signal to the at least one reflective surface comprises transmitting the radar signal from a wayside radar system to the at least one rail-mounted vehicle surface. In some embodiments, improving accuracy of vehicle location estimation based on radar signals includes: detecting the reflected radar signal; obtaining a unique radar signature of the guideway-mounted vehicle; obtaining positioning data identifying the wayside communication device or the wayside radar system; the vehicle location estimate is calculated based on the radar signals and the location data.

In some embodiments, a method of positioning a guideway-mounted vehicle includes: transmitting a first signal from the in-vehicle device to the wayside device; transmitting a second signal from the wayside unit to the in-vehicle device; obtaining a first vehicle location estimate based on the first signal; obtaining a second vehicle positioning estimate based on the second signal; comparing the first vehicle location estimate and the second vehicle location estimate to determine whether a difference between the first vehicle location estimate and the second vehicle location estimate is within a defined error range. In some embodiments, the method further comprises: a fusion algorithm is implemented to calculate a third vehicle location estimate based on the first vehicle location estimate and the second vehicle location estimate. In some embodiments: the vehicle-mounted device comprises a vehicle-mounted communication device; the first signal comprises a first communication signal; the wayside device comprises a wayside communication device; the second signal includes a second communication signal. In some embodiments, the method further comprises: transmitting a first radar signal from the vehicle radar system to at least one reflector; transmitting a second radar signal from the wayside radar system to at least one reflective surface of the rail mounted vehicle; obtaining a third vehicle positioning estimate based on the first radar signal; obtaining a fourth vehicle positioning estimate based on the second radar signal; wherein comparing the first vehicle location estimate and the second vehicle location estimate to determine whether a difference between the first vehicle location estimate and the second vehicle location estimate is within a defined error range includes comparing the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate to determine whether a difference between the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate is within the error range. In some embodiments, the method further comprises: a fusion algorithm is implemented based on the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate to calculate a fifth vehicle location estimate. In some embodiments, the method further comprises: the vehicle-mounted device comprises a vehicle-mounted radar system; the first signal comprises a first radar signal; the wayside device comprises a wayside radar system; the second signal includes a second radar signal.

In some embodiments, a method of positioning a guideway-mounted vehicle includes: transmitting the communication signal to the in-vehicle communication device; obtaining a vehicle positioning estimate based on the communication signal; transmitting radar signals to at least one reflective surface of the guideway-mounted vehicle; and improving accuracy of the range estimation based on the radar signal.

In some embodiments, a method of positioning a guideway-mounted vehicle includes: transmitting radar signals from the vehicle-mounted radar device to at least one reflector; obtaining a vehicle positioning estimate based on the radar signal; and measuring a vehicle speed estimate based on the radar signal.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. A method of positioning a guideway-mounted vehicle, the method comprising:

transmitting the communication signal to a wayside communication device;

obtaining a vehicle positioning estimate based on the communication signal;

transmitting radar signals to at least one reflector; and

and improving the accuracy of the vehicle positioning estimation based on the radar signal.

2. The method of claim 1, wherein obtaining the distance estimate based on the communication signal comprises obtaining a signal-to-noise ratio range distance correlation based on a signal-to-noise ratio distribution of the communication signal, the signal-to-noise ratio range distance correlation correlating the distance estimate with a signal-to-noise ratio of the communication signal.

3. The method of claim 1, wherein the at least one reflector comprises a reflector array having reflectors configured to reflect the radar signals such that the reflected radar signals have unique radar signatures, and wherein improving accuracy of the range estimation based on the radar signals comprises:

detecting the reflected radar signal;

identifying a unique radar signature of the reflected radar signal;

associating the at least one reflector with the wayside communication device based on the unique radar signature; and

A stored position of at least one of the at least one reflector is obtained based on an association between the at least one reflector and the wayside communication device.

4. The method of claim 1, wherein the obtaining the range estimate based on the communication signal comprises:

measuring a time of flight of the communication signal transmitted from the on-board communication device to the wayside communication device and returned to the on-board communication device; and

a measurement distance is determined based on the time of flight.

5. The method of claim 1, wherein the at least one reflector comprises a first reflector, and wherein improving accuracy of the range estimation based on the radar signal comprises:

the time of flight of the radar signal transmitted from an on-board radar system to the first reflector and back to the on-board radar system is measured, wherein the on-board radar system is on the guideway-mounted vehicle.

6. The method of claim 1, wherein the obtaining the range estimate based on the communication signal comprises:

measuring an angle of departure of the communication signal from an on-board communication device to the wayside communication device;

Measuring an angle of arrival of a second communication signal from the wayside communication device to the in-vehicle communication device; and

a location of the guideway-mounted vehicle is determined based on the distance estimate, the departure angle, and the arrival angle.

7. The method according to claim 1, wherein:

transmitting the communication signal to a wayside communication device comprising an antenna transmitting the communication signal to the wayside communication device, wherein the antenna is at least partially enclosed by a radome transparent to baseband frequencies of the communication signal, wherein at least one reflector comprises the radome;

transmitting the radar signal to the at least one reflector, comprising transmitting the radar signal to a radome of the roadside communication device, wherein the radome is retroreflective of baseband frequencies of radar signals.

8. The method of claim 7, wherein:

the baseband frequency of the communication signal is between 500MHz and 65 GHz; and

the baseband frequency of the radar signal is between 76GHz and 81 GHz.

9. The method according to claim 1, wherein:

transmitting the radar signal to the at least one reflector, including transmitting the radar signal to a reflector array;

Wherein improving accuracy of the range estimation based on the radar signals includes measuring time of flight to the reflector array, wherein each of the time of flight is a time of flight corresponding to a different reflector in the reflector array.

10. The method of claim 9, wherein the improving accuracy of the location estimate based on the radar signals further comprises implementing a fusion algorithm that calculates an estimated location of the guideway-mounted vehicle based on the distance estimate, departure angle, and arrival angle.

11. The method of claim 1, wherein the transmitting the radar signal to the at least one reflector comprises transmitting the radar signal to a first reflector, and wherein the method further comprises transmitting a second radar signal to a second reflector.

12. The method of claim 11, wherein improving the accuracy of the location estimate based on the radar signal comprises implementing a fusion algorithm that calculates an estimated location of the guideway-mounted vehicle based on the range estimate, the radar signal, and the second radar signal.

13. An on-board communication system for a rail mounted vehicle, comprising:

at least one wireless communication device;

at least one radar device;

a non-transitory computer readable medium configured to store computer executable instructions; and

at least one processor operably associated with the at least one wireless communication device, the at least one radar device, and the non-transitory computer-readable medium, wherein the at least one processor, when executed by the at least one processor, is configured to:

transmitting a communication signal from the at least one wireless communication device to a wayside communication device;

obtaining a range estimate based on the communication signal;

obtaining an angle of arrival and an angle of departure based on the communication signal;

transmitting radar signals from the at least one radar device to at least one reflector;

obtaining a second angle of arrival and a second angle of departure based on the radar signal; and

accuracy of vehicle positioning estimation is improved based on radar signals.

14. The vehicle-mounted communication system of claim 13, wherein the distance estimate is obtained based on the communication signal, the at least one processor configured to obtain a signal-to-noise ratio range distance estimate that relates distance estimates to signal-to-noise ratios of the communication signal based on a signal-to-noise ratio distribution of the communication signal.

15. The vehicle-mounted communication system of claim 13, wherein the at least one reflector comprises a reflector array having reflectors configured to reflect the radar signals such that the reflected radar signals have unique radar signatures, and wherein the at least one processor is configured to promote accuracy of the range estimation based on the radar signals by:

detecting the reflected radar signal;

identifying a unique radar signature of the reflected radar signal;

associating the wayside communication device with the unique radar signature; and

based on the unique radar signature and the association of the reflector array with the wayside communication device, a stored location of at least one of the at least one reflector is obtained.

16. The vehicle-mounted communication system of claim 13, wherein the at least one processor is configured to promote accuracy of the location estimate based on the radar signal by:

measuring a second angle of departure of the radar signal from a vehicle radar to a reflector, wherein the at least one radar device comprises the vehicle radar and the at least one reflector comprises the reflector;

Measuring a second angle of arrival of radar signals from the reflector to the vehicle radar;

a position of the rail mounted vehicle is determined based on the second departure angle, the second arrival angle, and the distance estimate.

17. The vehicle-mounted communication system of claim 13, wherein the at least one processor is configured to obtain the location estimate based on the communication signal by:

measuring an angle of departure of a second communication signal from the in-vehicle communication device to the roadside communication device; and

the position of the guideway-mounted vehicle is determined based on the angle of arrival of the second communication signal, the angle of departure of the second communication signal, and the distance estimate.

18. The in-vehicle communication system according to claim 13, wherein:

transmitting the communication signal to a wayside communication device comprising an antenna transmitting the communication signal to the wayside communication device, wherein the antenna is at least partially enclosed by a radome transparent to baseband frequencies of the communication signal, wherein at least one reflector comprises a radome;

Transmitting the radar signal to at least one reflector, comprising transmitting the radar signal to a radome of a roadside communication device, wherein the radome is retroreflective to a baseband frequency of the radar signal.

19. A method of positioning a guideway-mounted vehicle, the method comprising:

transmitting a communication signal to an antenna on a wayside communication device, wherein the antenna is at least partially enclosed by a radome, the radome being transparent to baseband frequencies of the communication signal;

obtaining a range estimate based on the communication signal;

transmitting radar signals to the wayside communication device, wherein the radome is retroreflective of baseband frequencies of radar signals; and

and improving the accuracy of the distance estimation based on the radar signals.

20. The method of claim 19, wherein obtaining the distance estimate based on the communication signal comprises obtaining the distance estimate based on a signal-to-noise ratio distribution of the communication signal that is a result of a distance between the wayside communication device and an on-board communication device that transmitted the communication signal.

21. A method of positioning a guideway-mounted vehicle, the method comprising:

Transmitting communication signals between the vehicle-mounted communication device and the roadside communication device;

obtaining a vehicle positioning estimate based on the communication signal;

transmitting radar signals to at least one reflective surface; and

22. The method of claim 21, wherein transmitting the communication signal between the in-vehicle communication device and the wayside communication device comprises:

transmitting the communication signal from the in-vehicle communication device to the roadside communication device.

23. The method of claim 21, wherein the obtaining the vehicle location estimate based on the communication signal comprises:

receiving a second communication signal from the wayside communication device to the in-vehicle communication device in response to the communication signal transmitted from the in-vehicle communication device, wherein the second communication signal is modulated to include a unique identification for the wayside communication device;

obtaining a unique identification of the wayside communication device from the second communication signal;

obtaining location data identifying a wayside location of the wayside communication device based on the unique identification; and

the vehicle location estimate is calculated based on the location data and at least one of the communication signals and the second communication signal.

24. The method of claim 23, wherein transmitting the communication signal between the in-vehicle communication device and the wayside communication device comprises:

transmitting the communication signal from the roadside communication device to the in-vehicle communication device.

25. The method of claim 24, wherein the communication signal is modulated to include a unique identification of the wayside communication device, wherein obtaining the vehicle location estimate based on the communication signal comprises:

transmitting a second communication signal from the in-vehicle communication device to the roadside communication device in response to the communication signal transmitted from the roadside communication device;

26. The method of claim 21, wherein the at least one reflective surface comprises at least one reflector alongside a roadway of a guideway, wherein transmitting the radar signal to the at least one reflective surface comprises:

Transmitting the radar signal from the vehicle radar system to the at least one reflector.

27. The method of claim 26, wherein improving accuracy of the vehicle location estimate based on the radar signal comprises:

detecting the reflected radar signal;

identifying a unique radar signature of the at least one reflector from the reflected radar signal;

obtaining location data of the at least one reflector or the wayside communication device from a database based on the unique radar signature; and

the vehicle location estimate is calculated based on the radar signals and the location data.

28. The method of claim 27, wherein the at least one reflector comprises at least one retro-reflector alongside the rail.

29. The method according to claim 27, wherein:

the wayside communication device comprises one or more antennas; and

the at least one reflector includes a radome at least partially encapsulating the one or more antennas.

30. The method of claim 21, wherein the at least one reflective surface comprises at least one guideway-mounted vehicle surface, and wherein transmitting the radar signal to the at least one reflective surface comprises:

Transmitting the radar signal from the wayside radar system to the at least one guideway-mounted vehicle surface.

31. The method of claim 30, wherein the improving the accuracy of the vehicle location estimate based on the radar signal comprises:

detecting the reflected radar signal;

obtaining a unique radar signature of the guideway-mounted vehicle;

obtaining positioning data identifying a positioning of the wayside communication device or the wayside radar system;

32. A method of positioning a guideway-mounted vehicle, comprising:

transmitting a first signal from the in-vehicle device to the wayside device;

transmitting a second signal from the wayside unit to the in-vehicle device;

obtaining a first vehicle location estimate based on the first signal;

obtaining a second vehicle positioning estimate based on the second signal;

comparing the first vehicle location estimate and the second vehicle location estimate to determine whether a difference between the first vehicle location estimate and the second vehicle location estimate is within a defined error range.

33. The method of claim 32, further comprising:

A fusion algorithm is implemented to calculate a third vehicle location estimate based on the first vehicle location estimate and the second vehicle location estimate.

34. The method according to claim 32, wherein:

the vehicle-mounted device comprises a vehicle-mounted communication device;

the first signal comprises a first communication signal;

the wayside device comprises a wayside communication device;

the second signal includes a second communication signal.

35. The method of claim 34, further comprising:

transmitting a first radar signal from the vehicle radar system to at least one reflector;

transmitting a second radar signal from the wayside radar system to at least one reflective surface of the rail mounted vehicle;

obtaining a third vehicle positioning estimate based on the first radar signal;

obtaining a fourth vehicle positioning estimate based on the second radar signal;

wherein comparing the first vehicle location estimate and the second vehicle location estimate to determine whether a difference between the first vehicle location estimate and the second vehicle location estimate is within a defined error range includes comparing the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate to determine whether a difference between the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate is within the error range.

36. The method of claim 35, further comprising:

a fusion algorithm is implemented based on the first vehicle location estimate, the second vehicle location estimate, the third vehicle location estimate, and the fourth vehicle location estimate to calculate a fifth vehicle location estimate.

37. The method of claim 32, further comprising:

the vehicle-mounted device comprises a vehicle-mounted radar system;

the first signal comprises a first radar signal;

the wayside device comprises a wayside radar system;

the second signal includes a second radar signal.

38. A method of positioning a guideway-mounted vehicle, comprising:

transmitting the communication signal to the in-vehicle communication device;

obtaining a vehicle positioning estimate based on the communication signal;

transmitting radar signals to at least one reflective surface of the guideway-mounted vehicle; and

and improving the accuracy of the positioning estimation based on the radar signals.

39. A method of positioning a guideway-mounted vehicle, the method comprising:

transmitting radar signals from the vehicle-mounted radar device to at least one reflector;

obtaining a vehicle positioning estimate based on the radar signal; and

the vehicle speed estimate is measured based on the radar signal.