CN111670568A

CN111670568A - Data synchronization method, distributed radar system and movable platform

Info

Publication number: CN111670568A
Application number: CN201980005511.3A
Authority: CN
Inventors: 陆龙; 何欢; 边亚斌; 刘祥
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2019-01-08
Filing date: 2019-01-08
Publication date: 2020-09-15
Also published as: WO2020142909A1

Abstract

A data synchronization method, a distributed radar system and a movable platform are provided, the data synchronization method is applied to the distributed radar system, the distributed radar system comprises at least two radars, and the method comprises the following steps: generating a first synchronization signal (S101); sending a first synchronization signal to at least two radars and acquiring measurement data of the at least two radars; wherein the first synchronization signal is used to synchronize acquisition times of the measurement data (S102). The method can synchronize the acquisition time of the measurement data of each radar in the distributed radar system, thereby ensuring that the measurement data of each radar is acquired at the same time when the measurement data of each radar is subjected to fusion processing, and ensuring the accuracy of the fusion processing.

Description

Data synchronization method, distributed radar system and movable platform

Description

Technical Field

The present invention generally relates to the field of radar technology, and more particularly, to a data synchronization method, a distributed radar system, and a movable platform.

Background

In practical application, radar is often used for detecting a target scene. Taking a laser radar as an example, the principle of the method is that a laser pulse signal is actively emitted outwards, a reflected echo signal is detected, and the distance of a measured object is judged according to the time difference between emission and reception; and the three-dimensional depth information of the target scene can be obtained by combining the emission direction information of the light pulse.

In the distributed radar system, the radars are respectively arranged at different positions to detect information of each direction of a target scene, and how to ensure the synchronization of the measured data of each radar in the multi-radar system becomes a problem which needs to be solved.

Disclosure of Invention

The present invention has been made to solve at least one of the above problems. The invention provides a data synchronization method which can synchronize the acquisition time of the measurement data of each radar in a distributed radar system, thereby ensuring that the measurement data of each radar is acquired at the same time when the measurement data of each radar is subjected to fusion processing, and ensuring the accuracy of the fusion processing.

Specifically, an embodiment of the present invention provides a data synchronization method, where the data synchronization method is applied to a distributed radar system, where the distributed radar system includes at least two radars, and the method includes:

generating a first synchronization signal;

sending the first synchronization signal to the at least two radars and acquiring measurement data of the at least two radars;

wherein the first synchronization signal is used for synchronizing acquisition time of the measurement data.

An embodiment of the present invention further provides a distributed radar system, including: at least two radars, and one or more processors;

the one or more processors are configured for generating a first synchronization signal;

An embodiment of the present invention further provides a movable platform, which includes:

a body;

the power system is arranged on the machine body and used for providing power for the movable platform;

and a distributed radar system as described above.

The embodiment of the invention provides a data synchronization method, a distributed radar system and a movable platform, which synchronize the acquisition time of the measurement data of each radar in the distributed radar system by sending a synchronization signal to the radar, thereby ensuring that the measurement data of each radar is acquired at the same time when the measurement data of each radar is subjected to fusion processing, and ensuring the accuracy of the fusion processing.

Drawings

FIG. 1 shows a schematic block diagram of a distributed radar system;

FIG. 2 shows a schematic flow diagram of a data synchronization method according to an embodiment of the invention;

FIG. 3 shows a schematic flow diagram of a data synchronization method according to another embodiment of the invention;

FIG. 4 shows a schematic block diagram of a distributed radar system according to an embodiment of the present invention;

FIG. 5 shows a schematic block diagram of a ranging device according to an embodiment of the invention;

fig. 6 is a schematic configuration diagram showing a distance detecting apparatus according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a subset of embodiments of the invention and not all embodiments of the invention, with the understanding that the invention is not limited to the example embodiments described herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention described herein without inventive step, shall fall within the scope of protection of the invention.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In the following description, for the purposes of thorough understanding of the present invention, detailed procedures and detailed structures are set forth in order to explain the present invention, but the present invention may be embodied in other specific forms besides those detailed description.

Fig. 1 shows a schematic block diagram of a distributed radar system. As shown in fig. 1, the distributed radar system 100 includes a control system 10 and N radars, where the N radars are distributed at different positions and used for detecting object information at different positions/directions, and the control system 10 performs comprehensive processing according to the object information detected by the N radars, so as to know the object information of the surrounding environment. For example, after the distributed radar system is arranged on an automobile, the object information of different directions around the automobile is detected through the N radars, so that the object information of the environment around the automobile is known.

The control system 10 may include one or more processors for receiving and processing data transmitted by the radars 1-N and for controlling the operation of the radars 1-N and other modules. The control system 10 is connected to N radar interfaces to which radars can be connected via transmission cables 20, so that the radars are connected to the control system 10, and the control system 10 receives data of the radars and controls the radars.

The radar may be a laser radar, an ultrasonic radar, a millimeter wave radar or other ranging device or range detection device.

In the distributed radar system, how to ensure synchronization of the radar measurement data and ensure that point cloud image data fused with the radar measurement data are acquired at the same time becomes a problem to be solved.

The data synchronization method and the distributed radar system provided by the embodiment of the invention are described below with reference to fig. 2 to 4.

An embodiment of the present invention provides a data synchronization method, which is applied to a distributed radar system, such as shown in fig. 1, and includes at least two radars and one or more processors.

Fig. 2 shows a schematic flow diagram of a data synchronization method according to an embodiment of the invention. As shown in fig. 2, the data synchronization method provided in this embodiment includes:

step S101 generates a first synchronization signal.

Illustratively, the first synchronization signal is generated, for example, by one or more processors of the distributed radar system, for example, a Pulse Per Second (PPS) signal, and the Processor is, for example, a Micro Processor Unit (MCU) or a Central Processing Unit (CPU).

Step S102, the first synchronization signal is sent to the at least two radars, and the measurement data of the at least two radars are obtained.

That is, after a first synchronization signal is generated, the first synchronization signal is sent to the at least two radars and measurement data of the at least two radars is acquired, wherein the first synchronization signal is used for synchronizing acquisition time of the measurement data.

Illustratively, the measurement data includes point cloud data generated by a radar detection target scene. Each point in the point cloud data includes coordinates of a three-dimensional point and characteristic information of the corresponding three-dimensional point, such as depth information, angle information, reflectivity information, and the like. The acquisition time of the measurement data corresponds to the time of the rising edge/falling edge of the pulse of the first synchronization signal, so that when the measurement data received from each radar is acquired, when the measurement data from the at least two radars are subjected to fusion processing, the fused measurement data can be ensured to be acquired at the same time instead of the measurement data acquired at different times, and the accuracy of the measurement data fusion processing of the multiple radars is ensured.

Further, the data synchronization method according to the present embodiment is also used to achieve synchronization of measurement data of the radar within the distributed radar system and data of an external device outside the distributed radar system. Examples of the external device include various sensors including an image sensor, a position sensor, a vision sensor, and an attitude sensor, and the position sensor includes, but is not limited to, a Global Positioning System (GPS), a compass, a GLONASS (Global Navigation Satellite System), and a Galileo (Galileo) Positioning sensor.

Therefore, the data synchronization method of the embodiment further includes sending the first synchronization signal to a sensor and receiving the measurement data of the sensor, where the first synchronization signal is used to synchronize the acquisition time of the measurement data of the sensor, and specifically, the acquisition time of the measurement data of the sensor corresponds to the time of the rising edge/falling edge of the pulse of the first synchronization signal, so that when the fusion processing is performed on the measurement data from the at least two radars and the measurement data of the sensor, it is ensured that the fused measurement data are acquired at the same time, but not the measurement data acquired at different times, thereby ensuring the accuracy of the fusion processing of the measurement data of multiple radars and sensors.

Further, the measurement data may be sent to the at least two radars via a transceiver, which may include, for example, an RS-485 interface, a Controller Area Network (CAN) interface, or an ethernet 1588 interface. The transceiver may be integrated in the processor of the distributed radar system or may be separately disposed between the processor of the distributed radar system and the radar and external devices. And in order to suppress damage to the chip (i.e. the processor) from common mode levels, an isolation circuit, such as an opto-coupler isolation circuit or an isolation circuit formed by discrete components, is provided between each of the transceivers and the one or more processors.

Fig. 3 shows a schematic flow diagram of a data synchronization method according to another embodiment of the invention. As shown in fig. 2, the radar access detection method provided in this embodiment includes:

step S201, receiving a second synchronization signal sent by an external device. Such as a sensor or a timestamp server. That is, the second synchronization signal includes a timestamp signal transmitted by a timestamp server or a synchronization signal transmitted by a sensor. The sensors include image sensors, position sensors, vision sensors and attitude sensors, and the position sensors include but are not limited to positioning sensors such as GPS, Beidou, GLONASS, Galileo and the like.

Step S102, sending the second synchronization signal to the at least two radars, and acquiring measurement data of the at least two radars, wherein the second synchronization signal is used for synchronizing acquisition time of the measurement data.

As an example, the distributed radar system receives a timestamp signal from the timestamp server and transmits the timestamp signal as a second synchronization signal to the at least two radars, so as to synchronize the measurement data of the at least two radars, so that when the fusion processing is performed on the measurement data from the at least two radars, it is ensured that the fused measurement data are obtained at the same time, but not the measurement data obtained at different times, thereby ensuring the accuracy of the fusion processing of the measurement data of multiple radars.

As another example, the distributed radar system receives a timestamp signal from the timestamp server and transmits the timestamp signal as a second synchronization signal to the at least two radars and the one or more external sensors, thereby synchronizing the measurement data of the at least two radars and the one or more external sensors, so that when the fusion processing is performed on the measurement data from the at least two radars and the measurement data of the one or more external sensors, it is possible to ensure that the fused measurement data are obtained at the same time, but not the measurement data obtained at different times, thereby ensuring the accuracy of the fusion processing of the measurement data of the multiple radars and sensors.

As still another example, the distributed radar system receives a synchronization signal from an external sensor and transmits the synchronization signal as a second synchronization signal to the at least two radars, thereby synchronizing the measurement data of the at least two radars or the at least two radars and the one or more external sensors, so that when the fusion process is performed on the measurement data from the at least two radars or the measurement data of the at least two radars and the measurement data of the one or more external sensors, it can be ensured that the fused measurement data are obtained at the same time, not the measurement data obtained at different times, thereby ensuring the accuracy of the measurement data fusion process of the multiple radars and sensors.

It should be understood that the external device not only comprises the sensor or the timestamp server, but also may be a separate synchronization signal generating means which generates synchronization signals to be sent to the at least two radars and the one or more external sensors for synchronizing the measurement data of the at least two radars and the one or more external sensors.

In one embodiment, the first synchronization signal and the second synchronization signal in the embodiments shown in fig. 2 and fig. 3 may be used separately or simultaneously.

In one embodiment, after the distributed radar system is powered on, the first synchronization signal in the embodiment shown in fig. 2 is used first, and when the second synchronization signal sent by the external device is received, the second synchronization signal in the embodiment shown in fig. 3 is used. The distributed radar system can switch the first synchronous signal and the second synchronous signal so as to meet the synchronization requirements of different scenes.

In addition, in the embodiment shown in fig. 3, the transmission of the second synchronization signal is also implemented by the transceiver, and the setting manner of the transceiver is as described above, which is not described herein again.

FIG. 4 shows a schematic block diagram of a distributed radar system according to an embodiment of the present invention. As shown in fig. 4, the distributed radar system 400 of the present embodiment includes at least two radars 410 to 41n, n being greater than or equal to 2, one or more transceivers 420, and one or more processors 430.

At least two radars 410 to 41n are used for target scene detection to obtain measurement data. The measurement data includes point cloud data generated by a radar detecting a target scene. Each point in the point cloud data includes coordinates of a three-dimensional point and characteristic information of the corresponding three-dimensional point, such as depth information, angle information, reflectivity information, and the like.

Transceiver 420 is used to enable signal transmission between radars 410-41n and one or more processors 430. The number of transceivers 420 is configured as desired. The transceiver 420 may be integrated with one or more of the processors 43 or may be separate. Illustratively, in this embodiment, one or more transceivers 420 are integrated with the one or more processors 430 for receiving/transmitting signals, such as synchronization signals or measurement data. The transceiver 420 comprises, for example, an RS-485 interface, a CAN interface, or an ethernet 1588 interface. Furthermore, in order to suppress damage to the chip (i.e., the processor 430) due to common mode levels, an isolation circuit (not shown), such as an optical coupling isolation circuit or an isolation circuit formed by discrete components, is provided between each of the transceivers 420 and the one or more processors 430.

The one or more processors 430 are configured to generate and transmit a first synchronization signal to the at least two radars 410 to 41n, and acquire measurement data of the at least two radars 410 to 41 n. The first synchronization signal is used for synchronizing acquisition time of the measurement data. The processor 430 is, for example, an MCU or a CPU. The first synchronization signal is, for example, a PPS signal.

The one or more processors 430 are configured to perform a fusion process on the measurement data from the at least two radars 410 to 41 n. Since the measurement data of the at least two radars 410 to 41n are synchronized by the first synchronization signal, for example, the acquisition time of the measurement data corresponds to the time of the pulse rising edge/falling edge of the first synchronization signal, when the fusion processing is performed on the measurement data from the at least two radars 410 to 41n, it is ensured that the fused measurement data are acquired at the same time, but not the measurement data acquired at different times, thereby ensuring the accuracy of the measurement data fusion processing of multiple radars.

Further, in this embodiment, the synchronization signal may be generated by the one or more processors 430 themselves, or may be received from the external device 440. The external device 440 includes, for example, one or more sensors 441 and a timestamp server 442. The sensors 441 include image sensors, position sensors, vision sensors, and attitude sensors, and the position sensors include, but are not limited to, positioning sensors such as GPS, compass, GLONASS, Galileo, and the like.

Therefore, in this embodiment, the one or more processors 430 may be further configured to receive a second synchronization signal sent by the external device 440, and send the second synchronization signal to the at least two radars 410 to 41n, where the second synchronization signal is used to synchronize the acquisition time of the measurement data of the at least two radars 410 to 41 n. Illustratively, the acquisition time of the measurement data corresponds to the time of the rising/falling edge of the pulse of the second synchronization signal. Illustratively, the second synchronization signal includes a synchronization signal transmitted by the sensor 441 or a timestamp signal transmitted by the timestamp server 442.

Further, based on the second synchronization signal, the one or more processors 430 may also be configured to perform a fusion process on the measurement data from the at least two radars 410 to 41n and the measurement data of the one or more sensors 441. Furthermore, in order to perform the fusion process on the measurement data from the at least two radars 410 to 41n and the measurement data of the one or more sensors 441, the one or more processors 430 may be further configured to transmit the first synchronization signal to the sensor 441 and receive the measurement data of the sensor 441.

As an example, the one or more processors 430 receive a timestamp signal from the timestamp server 442 and transmit the timestamp signal as a second synchronization signal to the at least two radars 410-41n to synchronize the measurement data of the at least two radars 410-41n, so that when the fusion processing is performed on the measurement data from the at least two radars 410-41n, it is ensured that the fused measurement data are obtained at the same time, but not at different times, thereby ensuring the accuracy of the measurement data fusion processing of multiple radars.

As another example, the one or more processors 430 receive a time stamp signal from the time stamp server 442 and transmit the time stamp signal as a second synchronization signal to the at least two radars 410-41n and the one or more external sensors 441, thereby synchronizing the measurement data of the at least two radars 410-41n and the one or more external sensors 441, so that when the fusion processing is performed on the measurement data from the at least two radars 410-41n and the measurement data of the one or more external sensors 441, it can be ensured that the fused measurement data are obtained at the same time, not the measurement data obtained at different times, thereby ensuring the accuracy of the measurement data fusion processing of the multiple radars and sensors.

As yet another example, the one or more processors 430 receive a synchronization signal from the external sensor 441 and transmit the synchronization signal as a second synchronization signal to the at least two radars 410-41n, thereby synchronizing the measurement data of the at least two radars 410-41n or the at least two radars 410-41n and the one or more external sensors 441, so that when the fusion process is performed on the measurement data from the at least two radars 410-41n or the measurement data of the at least two radars 410-41n and the measurement data of the one or more external sensors 441, it can be ensured that the fused measurement data are obtained at the same time, but not the measurement data obtained at different times, thereby ensuring the accuracy of the measurement data fusion process of the multiple radars and sensors.

It should be understood that the external device 440 not only includes the sensor 441 or the timestamp server 442, but also may be a separate synchronization signal generating means that generates a synchronization signal to be transmitted to the at least two radars 410-41n and the one or more external sensors 441 to synchronize the measurement data of the at least two radars 410-41n and the one or more external sensors 441.

In one embodiment, the first synchronization signal and the second synchronization signal in this embodiment may be used separately or simultaneously.

The radar related to the invention can be a laser radar, and also can be other radars or distance measuring devices. For a better understanding of the invention, the principle and structure of the distance measuring device are described below by way of example. The distance measuring device can be electronic equipment such as a laser radar, laser distance measuring equipment and the like. In one embodiment, the ranging device is used to sense external environmental information, such as distance information, orientation information, reflected intensity information, etc. of environmental targets. In one implementation, the ranging device may detect the distance of the probe to the ranging device by measuring the Time of Flight (TOF), which is the Time-of-Flight Time, of light traveling between the ranging device and the probe. Alternatively, the distance measuring device may detect the distance from the probe to the distance measuring device by other techniques, such as a distance measuring method based on phase shift (phase shift) measurement or a distance measuring method based on frequency shift (frequency shift) measurement, which is not limited herein.

For ease of understanding, the following describes an example of the ranging operation with reference to the ranging apparatus 500 shown in fig. 5.

As shown in fig. 5, the ranging apparatus 500 may include a transmitting circuit 110, a receiving circuit 120, a sampling circuit 130, and an operation circuit 140.

The transmit circuitry 110 may transmit a sequence of light pulses (e.g., a sequence of laser pulses). The receiving circuit 120 may receive the optical pulse train reflected by the detected object, perform photoelectric conversion on the optical pulse train to obtain an electrical signal, process the electrical signal, and output the electrical signal to the sampling circuit 130. The sampling circuit 130 may sample the electrical signal to obtain a sampling result. The arithmetic circuit 140 may determine the distance between the distance measuring device 500 and the detected object based on the sampling result of the sampling circuit 130.

Optionally, the distance measuring apparatus 500 may further include a control circuit 150, and the control circuit 150 may implement control of other circuits, for example, may control an operating time of each circuit and/or perform parameter setting on each circuit, and the like.

It should be understood that, although the distance measuring device shown in fig. 5 includes a transmitting circuit, a receiving circuit, a sampling circuit and an arithmetic circuit for emitting a light beam to detect, the embodiments of the present application are not limited thereto, and the number of any one of the transmitting circuit, the receiving circuit, the sampling circuit and the arithmetic circuit may be at least two, and the at least two light beams are emitted in the same direction or in different directions respectively; the at least two light paths may be emitted simultaneously or at different times. In one example, the light emitting chips in the at least two transmitting circuits are packaged in the same module. For example, each transmitting circuit comprises a laser emitting chip, and die of the laser emitting chips in the at least two transmitting circuits are packaged together and accommodated in the same packaging space.

In some implementations, in addition to the circuit shown in fig. 5, the distance measuring apparatus 500 may further include a scanning module 160 for changing the propagation direction of at least one laser pulse sequence emitted from the emitting circuit.

Here, a module including the transmission circuit 110, the reception circuit 120, the sampling circuit 130, and the operation circuit 140, or a module including the transmission circuit 110, the reception circuit 120, the sampling circuit 130, the operation circuit 140, and the control circuit 150 may be referred to as a ranging module, which may be independent of other modules, for example, a scanning module.

The distance measuring device can adopt a coaxial light path, namely the light beam emitted by the distance measuring device and the reflected light beam share at least part of the light path in the distance measuring device. For example, at least one path of laser pulse sequence emitted by the emitting circuit is emitted by the scanning module after the propagation direction is changed, and the laser pulse sequence reflected by the detector is emitted to the receiving circuit after passing through the scanning module. Alternatively, the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are transmitted along different optical paths in the distance measuring device. FIG. 6 shows a schematic diagram of one embodiment of the ranging device of the present invention using coaxial optical paths.

Ranging device 600 includes a ranging module 201, ranging module 201 including an emitter 203 (which may include the transmit circuitry described above), a collimating element 204, a detector 205 (which may include the receive circuitry, sampling circuitry, and arithmetic circuitry described above), and a path-altering element 206. The distance measurement module 201 is configured to emit a light beam, receive return light, and convert the return light into an electrical signal. Wherein the emitter 203 may be configured to emit a sequence of light pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the emitter 203 is a narrow bandwidth beam having a wavelength outside the visible range. The collimating element 204 is disposed on an emitting light path of the emitter, and is configured to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light to be emitted to the scanning module. The collimating element is also for converging at least a portion of the return light reflected by the detector. The collimating element 204 may be a collimating lens or other element capable of collimating a light beam.

In the embodiment shown in fig. 6, the transmit and receive optical paths within the distance measuring device are combined by the optical path changing element 206 before the collimating element 204, so that the transmit and receive optical paths can share the same collimating element, making the optical path more compact. In other implementations, the emitter 203 and the detector 205 may use respective collimating elements, and the optical path changing element 206 may be disposed in the optical path after the collimating elements.

In the embodiment shown in fig. 6, since the beam aperture of the light beam emitted from the emitter 203 is small and the beam aperture of the return light received by the distance measuring device is large, the optical path changing element can adopt a small-area mirror to combine the emission optical path and the reception optical path. In other implementations, the optical path changing element may also be a mirror with a through hole, wherein the through hole is used for transmitting the outgoing light from the emitter 203, and the mirror is used for reflecting the return light to the detector 205. Therefore, the shielding of the bracket of the small reflector to the return light can be reduced in the case of adopting the small reflector.

In the embodiment shown in fig. 6, the optical path altering element is offset from the optical axis of the collimating element 204. In other implementations, the optical path altering element may also be located on the optical axis of the collimating element 204.

The ranging device 600 also includes a scanning module 202. The scanning module 202 is disposed on the emitting light path of the distance measuring module 201, and the scanning module 202 is configured to change the transmission direction of the collimated light beam 219 emitted by the collimating element 204, project the collimated light beam to the external environment, and project the return light beam to the collimating element 204. The return light is focused by a collimating element 204 onto a detector 205.

In one embodiment, the scanning module 202 may include at least one optical element for altering the propagation path of the light beam, wherein the optical element may alter the propagation path of the light beam by reflecting, refracting, diffracting, etc., the light beam. For example, the scanning module 202 includes a lens, mirror, prism, galvanometer, grating, liquid crystal, Optical Phased Array (Optical Phased Array), or any combination thereof. In one example, at least a portion of the optical element is moved, for example, by a driving module, and the moved optical element can reflect, refract, or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 202 may rotate or oscillate about a common axis 209, with each rotating or oscillating optical element serving to constantly change the direction of propagation of an incident beam. In one embodiment, the multiple optical elements of the scanning module 202 may rotate at different rotational speeds or oscillate at different speeds. In another embodiment, at least some of the optical elements of the scanning module 202 may rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated about different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or in different directions; or in the same direction, or in different directions, without limitation.

In one embodiment, the scanning module 202 includes a first optical element 214 and a driver 216 coupled to the first optical element 214, the driver 216 configured to drive the first optical element 214 to rotate about the rotation axis 209, such that the first optical element 214 redirects the collimated light beam 219. The first optical element 214 projects the collimated beam 219 into different directions. In one embodiment, the angle between the direction of the collimated beam 219 after it is altered by the first optical element and the axis of rotation 209 changes as the first optical element 214 is rotated. In one embodiment, the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated light beam 219 passes. In one embodiment, the first optical element 214 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, the first optical element 114 comprises a wedge prism that refracts the collimated beam 219.

In one embodiment, the scanning module 202 further comprises a second optical element 215, the second optical element 215 rotating around a rotation axis 209, the rotation speed of the second optical element 215 being different from the rotation speed of the first optical element 214. The second optical element 215 is used to change the direction of the light beam projected by the first optical element 214. In one embodiment, the second optical element 215 is coupled to another driver 217, and the driver 217 drives the second optical element 215 to rotate. The first optical element 214 and the second optical element 215 may be driven by the same or different drivers, such that the first optical element 214 and the second optical element 215 rotate at different speeds and/or turns, thereby projecting the collimated light beam 219 into different directions in the ambient space, which may scan a larger spatial range. In one embodiment, the controller 218 controls the

drivers

216 and 217 to drive the first optical element 214 and the second optical element 215, respectively. The rotation speed of the first optical element 214 and the second optical element 215 can be determined according to the region and the pattern expected to be scanned in the actual application. The

drives

216 and 217 may include motors or other drives.

In one embodiment, second optical element 215 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, second optical element 215 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, second optical element 215 comprises a wedge angle prism.

In one embodiment, the scan module 202 further comprises a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element comprises a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism having a thickness that varies along at least one radial direction. In one embodiment, the third optical element comprises a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotational directions.

Rotation of the optical elements in the scanning module 202 may project light in different directions, such as the directions of

light

211 and 213, and thus scan the space around the distance measuring device 600. When the light 211 projected by the scanning module 202 hits the object to be detected 210, a part of the light is reflected by the object to be detected 210 to the distance measuring device 600 in the opposite direction to the projected light 211. The return light 212 reflected by the object 210 passes through the scanning module 202 and then enters the collimating element 204.

The detector 205 is placed on the same side of the collimating element 204 as the emitter 203, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.

In one embodiment, each optical element is coated with an antireflection coating. Optionally, the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on a surface of a component in the distance measuring device, which is located on the light beam propagation path, or a filter is arranged on the light beam propagation path, and is used for transmitting at least a wave band in which the light beam emitted by the emitter is located and reflecting other wave bands, so as to reduce noise brought to the receiver by ambient light.

In some embodiments, the transmitter 203 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse reception time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this manner, the ranging apparatus 600 may calculate TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance of the probe 210 to the ranging apparatus 600.

The distance and orientation detected by rangefinder 600 may be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In one embodiment, the distance measuring device of the embodiment of the present invention may be applied to a movable platform, and the distance measuring device may be mounted on a platform body of the movable platform. The mobile platform with the distance measuring device can measure the external environment, for example, the distance between the mobile platform and an obstacle is measured for the purpose of avoiding the obstacle, and the external environment is mapped in two dimensions or three dimensions. In certain embodiments, the movable platform comprises at least one of an unmanned aerial vehicle, an automobile, a remote control car, a robot, a camera. When the distance measuring device is applied to the unmanned aerial vehicle, the platform body is a fuselage of the unmanned aerial vehicle. When the distance measuring device is applied to an automobile, the platform body is the automobile body of the automobile. The vehicle may be an autonomous vehicle or a semi-autonomous vehicle, without limitation. When the distance measuring device is applied to the remote control car, the platform body is the car body of the remote control car. When the distance measuring device is applied to a robot, the platform body is the robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.

In one embodiment, the distributed radar system of the present invention may be applied to a movable platform to detect external environments at multiple locations of the movable platform, and in some embodiments, the movable platform includes a body, and a power system mounted to the body to provide power to the movable platform; and a distributed radar system as according to the present embodiment. Optionally, the movable platform comprises at least one of an unmanned aerial vehicle, a car, or a robot.

Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the foregoing illustrative embodiments are merely exemplary and are not intended to limit the scope of the invention thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as set forth in the appended claims.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the technical solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present invention should not be construed to reflect the intent: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some of the modules according to embodiments of the present invention. The present invention may also be embodied as apparatus programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

The above description is only for the specific embodiment of the present invention or the description thereof, and the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

A data synchronization method applied to a distributed radar system including at least two radars, the method comprising:

generating a first synchronization signal;

sending the first synchronization signal to the at least two radars and acquiring measurement data of the at least two radars;

wherein the first synchronization signal is used for synchronizing acquisition time of the measurement data.
The data synchronization method according to claim 1, wherein the acquisition time of the measurement data corresponds to a time of a rising/falling edge of a pulse of the first synchronization signal.
The data synchronization method of claim 1, further comprising: and performing fusion processing on the measurement data from the at least two radars.
The data synchronization method of claim 1, further comprising:

and receiving a second synchronous signal sent by external equipment, and sending the second synchronous signal to the at least two radars, wherein the second synchronous signal is used for synchronizing the acquisition time of the measurement data.
The data synchronization method of claim 4, wherein the second synchronization signal comprises a timestamp signal sent by a timestamp server.
The data synchronization method of claim 4, wherein the second synchronization signal comprises a synchronization signal transmitted by a sensor.
The data synchronization method of claim 1, further comprising: and sending the first synchronization signal or the time stamp signal to a sensor and receiving the measurement data of the sensor.
The data synchronization method of claim 1, further comprising: the measurement data from the at least two radars and the measurement data of the sensor are subjected to a fusion process.
The data synchronization method according to claims 6-8, wherein the sensors comprise image sensors, position sensors, vision sensors, attitude sensors.
The data synchronization method of claim 1, wherein the radar comprises a laser radar, a millimeter wave radar, an ultrasonic radar.
The data synchronization method of claim 1, wherein the measurement data comprises point cloud data generated by a radar detection target scene.
The data synchronization method according to claim 4, wherein the distributed radar system comprises one or more processors, and transceivers are provided between the one or more processors and the at least two radars and between the one or more processors and the external device, for receiving/transmitting signals.
The data synchronization method of claim 1, wherein the distributed radar system comprises one or more processors integrated with a transceiver for receiving/transmitting signals.
A method for synchronizing data according to claim 12 or 13, characterized in that said transceiver comprises an RS-485 interface, a CAN interface or an ethernet 1588 interface.
A method for synchronizing data according to claim 12 or 13, characterized in that an isolation circuit is provided between each of said transceivers and said one or more processors.
A distributed radar system, comprising: at least two radars, and one or more processors;

the one or more processors are configured for generating a first synchronization signal;

sending the first synchronization signal to the at least two radars and acquiring measurement data of the at least two radars;

wherein the first synchronization signal is used for synchronizing acquisition time of the measurement data.
The distributed radar system according to claim 16, wherein the acquisition time of the measurement data corresponds to a time of a rising/falling edge of a pulse of the first synchronization signal.
The distributed radar system of claim 16, wherein the one or more processors are further configured to perform a fusion process on the measurement data from the at least two radars.
The distributed radar system of claim 16, wherein the one or more processors are further configured to receive a second synchronization signal transmitted from an external device and to transmit the second synchronization signal to the at least two radars, the second synchronization signal being configured to synchronize the acquisition time of the measurement data.
The distributed radar system of claim 19, wherein the second synchronization signal comprises a timestamp signal transmitted by a timestamp server.
The distributed radar system of claim 19, wherein the second synchronization signal comprises a synchronization signal transmitted by a sensor.
The distributed radar system of claim 16,

the one or more processors are further configured to send the first synchronization signal or the time stamp signal to a sensor and receive measurement data of the sensor.
The distributed radar system of claim 16,

the one or more processors are further configured to perform a fusion process on the measurement data from the at least two radars and the measurement data of the sensor.
The distributed radar system of any of claims 21-23, wherein the sensor comprises an image sensor, a position sensor, a vision sensor, and an attitude sensor.
The distributed radar system of claim 16, wherein the radar comprises a laser radar, a millimeter wave radar, and an ultrasonic radar.
The distributed radar system of claim 16, wherein the measurement data comprises point cloud data generated by a radar detection target scene.
The distributed radar system of claim 19, wherein transceivers are provided between the one or more processors and the at least two radars and between the one or more processors and the external device for receiving/transmitting signals.
The distributed radar system of claim 16, wherein the one or more processors are integrated with a transceiver for receiving/transmitting signals.
A distributed radar system according to claim 27 or claim 28 wherein the transceiver comprises an RS-485 interface, a CAN interface or an ethernet 1588 interface.
A distributed radar system according to claim 27 or claim 28 wherein an isolation circuit is provided between each transceiver and the one or more processors, the isolation circuit comprising an optocoupler.
A movable platform, comprising:

a body;

the power system is arranged on the machine body and used for providing power for the movable platform;

and a distributed radar system according to any one of claims 16 to 30.
The movable platform of claim 31, wherein the movable platform comprises a drone, an automobile, or a robot.