EP3999872A1 - Systéme de détection d'objets longue portée - Google Patents
Systéme de détection d'objets longue portéeInfo
- Publication number
- EP3999872A1 EP3999872A1 EP20740028.4A EP20740028A EP3999872A1 EP 3999872 A1 EP3999872 A1 EP 3999872A1 EP 20740028 A EP20740028 A EP 20740028A EP 3999872 A1 EP3999872 A1 EP 3999872A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sensors
- plane
- objects
- signals
- distance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/003—Bistatic radar systems; Multistatic radar systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/42—Simultaneous measurement of distance and other co-ordinates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
- G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
- G01S13/26—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
- G01S13/28—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses
- G01S13/284—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses
- G01S13/286—Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave with time compression of received pulses using coded pulses frequency shift keyed
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/04—Systems determining presence of a target
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
- G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
- G01S13/347—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using more than one modulation frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/42—Simultaneous measurement of distance and other co-ordinates
- G01S13/44—Monopulse radar, i.e. simultaneous lobing
- G01S13/4454—Monopulse radar, i.e. simultaneous lobing phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement
Definitions
- TITLE Long-range object detection system
- the present invention relates to the field of object detection systems, or radars. It relates in particular to detection systems used for three-dimensional (3D) localization.
- the armed forces deployed in theaters of operations are faced with increasingly diversified short-range threats (rockets, mortars, missiles, drones, small planes, vehicles, infantry, etc.).
- the means of surveillance currently available are generally adapted to the detection and localization of a particular type of threat, in particular in terms of detection distance capacity.
- a high point such as a geographical point, but such a point is not necessarily available
- the weight of the radar system places significant constraints on the structure of such a mast, its deployment and its maximum height, o under an airborne device such than a balloon filled with a light gas
- the dimensioning of the balloon is directly linked to the payload to be carried.
- a load of 35kg requires a balloon a few meters in length, while a load of 200kg requires a large balloon (greater than 25 meters).
- the implementation is therefore complex when the mass of the radar is greater than a few hundred kilograms, a large balloon having high acquisition and deployment costs.
- the energy consumption and cooling of these devices require large section power lines, the weight of which can lead to the permissible load being exceeded. The same is true when the airborne device is of a different nature, such as for example a drone.
- An aim of the invention is therefore to provide a detection device having an extended range on rockets, or other type of missiles, but also a simultaneous detection and 3D localization capability on air threats such as drones , helicopters and microlights, and / or vehicles and / or humans on the move, while ensuring that the cost of the device, its weight, its complexity of implementation and its complexity of deployment are lower than for known solutions .
- FIG. 1 very briefly represents the various components of a detection device.
- This comprises a radar processing device 101, in charge on the one hand of generating or playing a radar signal, and on the other hand of receiving one or more echo signals, and of implementing signal processing algorithms in order to locate objects in a 2-dimensional environment (2D) or three-dimensional (3D).
- 2D 2-dimensional environment
- 3D three-dimensional
- the radar processing device is connected to a transmission device 102
- the transmission device 102 therefore comprises a digital to analog converter (DAC) in order to convert the signals which are transmitted to it by the radar processing device when these are digital, a radiofrequency chain for amplifying and transposing the signal onto carrier frequency when it is received in baseband or on an intermediate frequency, as well as one or more transmitting antennas, such as for example an omnidirectional antenna such as a dipole or a directional antenna such as a patch antenna or network antenna.
- DAC digital to analog converter
- the radar processing device 101 receives signals from a signal reception device 103.
- the latter is configured to receive signals echoing the signals transmitted on one or more sensors.
- Each sensor comprises at least one radiating element, omnidirectional in a plane or directional depending on the configuration. These sensors can be networked to form a directional antenna.
- the signal reception device 103 is configured to acquire the signals received from one or more sensors according to given configuration parameters, such as for example times of reception, a frequency of reception and / or a direction of reception, and to transmit them to the radar processing device for analysis.
- Each sensor is connected to a radio frequency chain configured to filter and amplify the received signal, and to transpose it to baseband or frequency
- each sensor is also connected to an analog to digital signal converter (ADC).
- ADC analog to digital signal converter
- the radiofrequency chain and / or the analog to digital converter can be integrated into the sensor.
- the various elements of the detection system can be co-located or grouped together in a single item of equipment: this is then referred to as monostatic radar. They can also be broken down into several separate items of equipment: this is called bistatic radar when transmission and reception are separate.
- Co-located radars generally use the same antennas to transmit and receive signals, in order to reduce the size, weight and cost of the equipment.
- the radar processing device 101 is a calculation device, of
- DSP Digital Signal
- ASIC application Specifies Integrated Circuit
- FPGA field-Programmable Gâte Array
- the radar processing device From the signals emitted by the transmitting device and the signals received from the receiving device, the radar processing device detects and follows targets present in the space to be monitored. These are characterized by a distance, an azimuth and an elevation, and possibly by other parameters such as their Doppler speed for example. For this, many methods are known from the state of the art. Among them are phase or amplitude interferometric processing, such as Adcock's gratings, beam-forming techniques, or so-called high-resolution processing, such as, for example, the MUSIC algorithm (acronym for MUItiple Signal Classification).
- phase or amplitude interferometric processing such as Adcock's gratings, beam-forming techniques, or so-called high-resolution processing, such as, for example, the MUSIC algorithm (acronym for MUItiple Signal Classification).
- an Adcock array requires several antennas spaced apart by a deviation proportional to the wavelength of the signals
- an array antenna comprises a plurality of radiating elements spaced apart by a distance proportional to the wavelength.
- the dimensioning of radar systems is therefore closely linked to the frequency of the signals used.
- low frequency radars require large and widely spaced transmitting and receiving antennas, while high frequency radars are more compact.
- the three-dimensional detection requires the implementation of a directional antenna mechanically mobile along two axes or radiating elements distributed in two perpendicular planes.
- system for detecting the presence of objects and estimating their direction and distance in three dimensions including:
- a transmission device configured to transmit signals according to a colored transmission method in a foreground
- reception device comprising at least two sensors arranged in a second plane perpendicular to the first plane
- the processing means are configured to detect the presence of objects and estimate their direction and distance:
- the transmitting device and the receiving device are separate, the receiving device being raised relative to the transmitting device.
- each sensor comprises an omnidirectional radiating element in the foreground.
- the first plane is a horizontal plane, in which the sensors of the reception device are arranged in a vertical plane.
- the sensors of the reception device are then connected by a cable and suspended under an airborne device enabling them to be raised, such as an inflatable balloon or a drone.
- a single sensor is used to detect the presence of objects and estimate their direction and distance in the foreground, preferably the highest sensor.
- the first plane is a vertical plane and the sensors of the receiving device are arranged in a horizontal plane.
- the sensors of the reception device can then be placed in line, the system also having means for removing ambiguities in the position of the objects relative to the sensors in the horizontal plane.
- the sensors of the receiving device can also be arranged so as to form a triangle, the detection of the presence of objects and the estimation of their direction and distance in the horizontal plane being carried out for each branch of the triangle respectively, then combined so as to remove ambiguities about the position of objects relative to the sensors in the horizontal plane.
- the sensors of the reception device are connected to the
- the sensors further comprising means for converting the signals received into optical signals.
- the use of an optical fiber link makes it possible to reduce the mass of the cable making it possible to transmit the signals acquired by the sensors of the receiving equipment, and therefore the mass of all of the receiving equipment.
- distance in the second plane can be achieved by implementing an interferometry method or high-resolution processing on the signals received from at least two sensors of the receiving antenna.
- it can be implemented by exploiting the directivity of an array antenna formed by the at least two sensors of the receiving antenna.
- the invention also describes a method for implementing a detection of the presence of objects and for estimating their direction and distance in three dimensions in a detection system comprising: a transmission device configured to transmit signals according to a colored transmission method in a first plane,
- a reception device comprising at least two sensors arranged in a second plane perpendicular to the first plane, and
- the method comprises the steps of:
- FIG. 1 shows a system for detecting the presence of objects and estimating their direction and distance, or radar, as known from the state of the art
- FIG. 2 shows a first embodiment of a
- FIG. 3 shows a second embodiment of a
- FIG. 4 shows a third embodiment of a
- FIG. 5a represents the losses linked to the interference fringes, for equipment located at ground level
- FIG. 6 shows the steps of an embodiment of a method of implementing a detection of three-dimensional objects according to the invention
- the invention finds that the transmission device has a much greater weight than the reception device. This is due in particular to the mandatory presence of high power amplifiers, power electronics such as high capacity capacitors, elements necessary for cooling the amplifiers, as well as lines
- the invention proposes to separate the transmission part from the reception part, like a bistatic radar, and to raise the reception device as a priority. In this way, the mass of the load to be raised is reduced in significant proportions, which simplifies the implementation of the system, and makes it possible to improve the propagation conditions for the reception part at a lower cost. In addition, raising the receiving antenna significantly limits interference fringes and losses for low altitude targets.
- the invention proposes to rely on a method of colored emission of signals, also known under the name of simultaneous multiple emission.
- This process cited for example in the article "Colored emission for active radar antenna", Institut Le Chevalier, Laurent Savy, REE N ° 03, Revue de l'Electricotti et de / 'Electronique, March 2005, pages 48-52, consists in dividing the space in which the transmitting antenna emits into sub-networks using MIMO processing methods (acronym for "Multiple Input Multiple Output ”) or MISO (acronym for“ Multiple Input Single Output ”).
- European patent application EP 2 296 007 A1 describes a beam agile radar in which detection is carried out in a plane from the coloring of the signals, and in the orthogonal plane by beam formation.
- Figure 2 shows a first embodiment of a system of
- the detection system according to the invention also makes it possible to detect other objects and estimating their direction and distance in 3D according to the invention. Obviously to a person skilled in the art, the detection system according to the invention also makes it possible to detect other objects and estimating their direction and distance in 3D according to the invention. Obviously to a person skilled in the art, the detection system according to the invention also makes it possible to detect other objects and estimating their direction and distance in 3D according to the invention.
- the emission device 201 is arranged at the top of a telescopic mast self-supported by a vehicle, but it could also be directly installed on the ground.
- the height h 1 of the telescopic mast is constrained by the heavy weight of the emission device.
- the transmission device is configured so as to transmit a signal of
- the transmission device is connected to a radar processing device 230, which in the example is on board the carrier vehicle, but the arrangement of which does not matter.
- the reception device comprises several sensors 21 1 to 215 separated from the transmission device, arranged in line and vertically, thus together making up a reception network antenna.
- the sensors are connected by a cable to a high point such as an inflatable balloon 221 or to any other element making it possible to suspend the reception device (drone, crane, pylon, etc.), so that they are placed between the ground and the high point.
- the sensors of the receiving device are also connected to a radar processing device 230 by a cable 220 which ensures the transport of signals and power supplies.
- This cable can be the same as that ensuring the maintenance of the sensors, and / or that ensuring the maintenance in position of the balloon 221.
- the solution in which the cable used for the transmission of the signals is different from the cable maintaining the balloon 221 is however preferable. in order to facilitate the deployment and folding of the device. Due to the low weight of the sensors, the height h 2 of the highest sensor can be greater or much greater than the height h 1 to which the emission device 201 is fixed.
- An aim of the invention being to position the sensors of the reception device as high as possible in order to increase direct visibility and to reduce the interference fringes due to reflections on the ground, this aim is therefore achieved by virtue of the distinction between transmission device and reception device.
- the sensors of the reception device 21 1 to 215 comprise omnidirectional radiating elements in the horizontal plane, such as for example dipole antennas mounted vertically, which makes the equivalent antenna formed by the array of omnidirectional sensors in azimuth and directive in elevation.
- the sensors can also be directional if the purpose of the antenna is not to provide 360 ° surveillance in the horizontal plane.
- each sensor further comprises a low noise amplifier making it possible to raise the level of the signal before its transmission to the radar processing device 230.
- the transmission device 201 comprises a digital to analog converter.
- the sensors of the receiving device each include an analog to digital converter.
- the radar processing device comprises the reverse converters.
- the link connecting the sensors of the reception device to the radar processing device is an optical link.
- the use of optical fiber makes it possible to reduce the section and the mass of the cable 220.
- This solution is preferable to the use of a copper cable because it still makes it possible to lighten the device, and to position the sensors of the receiving antenna as high as possible. It also makes it possible to facilitate the deployment / folding of the receiving device.
- the sensors also each have converters of the received signals, analog or digital, to optical signals, to transmit the signals acquired by the radiating elements to the radar processing device, as well as, when they include a low noise amplifier. , an optical to electrical energy converter to power it.
- the radar processing device comprises the reverse converters.
- the mass of the receiving device being small compared to that of the transmitting device, it can be deployed at height much more easily than if it had been necessary to raise all the transmitting / receiving equipment.
- the detection of the objects and the estimation of their azimuth are carried out using the coloring properties of the signals. issued.
- This determination is made from the signal received from one of the sensors of the reception device according to methods known to those skilled in the art.
- the sensor selected for this purpose is the highest sensor, because it is the one for which the interference fringes are the smallest.
- this operation is carried out on the signals received from several sensors of the reception device. Estimating the azimuth of the objects detected using the coloring properties makes it possible to avoid having to have several series of sensors in parallel to create a directive array antenna in the horizontal plane.
- the one-dimensional array antenna formed by the sensors makes it possible to implement 3D localization methods which are usually only possible by using two-dimensional array antennas. The change from two to one dimension therefore makes it possible to reduce the size, cost and complexity of deploying / folding the device. This also makes it possible to have a larger antenna vertically than the known devices with constant weight.
- the radar processing device 230 determines their direction and distance in the vertical plane of the sensors 21 1 to 215 of the receiving device, are carried out by the radar processing device 230 from the signals received from all of the sensors or from a selection of at least two sensors, using the directivity properties of the array antenna thus formed.
- the selection of sensors used can be made on the basis of considerations relating to the operating frequency band, the spacing between the sensors, as well as the desired directivity performance and gain.
- the multi-sensor antenna can be used as a directive array antenna scanning the vertical plane, adjusting the phase and amplitude of the signals received from each of the sensors and recombining them to orient the antenna beam. Also, the signals received from at least two sensors can be exploited by an interferometry process or by high resolution processing.
- the detection can be carried out first in a first plane, for example in the horizontal plane to determine the azimuth of the object, then in a second plane, for example the vertical plane to determine the elevation considering the azimuth determined in the foreground. Detection can also be carried out simultaneously in both planes, which allows to benefit from a gain in processing to improve the precision of the measurement.
- the receiving device is deployed over a length
- the receiving antenna can then easily be positioned at very high heights using a reasonably sized balloon 221, a crane, or any other device allowing the receiving antenna to be hooked to a high point, and transporting large numbers of people. of sensors.
- the large height of the device allows to reduce so
- the interference fringes and losses for low altitude targets are considerable compared to transmitting / receiving equipment positioned at ground level or on top of a telescopic mast.
- the weight of the cable 220 becoming dimensioned as the height of the device increases, it can be
- the use of a large number of sensors in the reception device makes it possible to increase the gain of the equivalent antenna and to obtain a very high angular resolution in the vertical plane.
- FIG. 3 represents a second embodiment of a system for detecting the presence of objects and for estimating their direction and distance in three dimensions according to the invention.
- the antenna formed by the reception sensors is not arranged in the vertical plane but in the horizontal plane.
- the emission device 301 is arranged at the top of a telescopic mast
- the transmitting device comprises several radiating elements, and is configured to emit a signal in a colored manner in the vertical plane. This can be done from a directional antenna emitting a colored signal, the direction and color of which vary over time, or from an array antenna comprising several radiating elements each emitting a signal.
- the antenna beam can be directional or omnidirectional, in the horizontal plane and / or in the vertical plane. It is connected to a radar processing device 330.
- the receiving device comprises several sensors 31 1 to be separated from the
- the transmitting device arranged in line and horizontally, which makes the array antenna formed by the array of sensors omnidirectional in elevation and directional in azimuth when the sensors used are omnidirectional in the vertical plane.
- the sensors of the receiving device are connected by a cable which holds them in position.
- the cable is stretched between at least two pylons 321 and 322, so that the sensors are placed at a height h 3 , but the latter could equally be each placed at the top of a pylon or a mast.
- the sensors of the reception device are connected to the radar processing device 330 by a cable 320 which ensures the transport of signals and power supplies. This cable can be the same as that ensuring the maintenance of the sensors, or be an independent cable.
- each sensor can be connected independently to the device 330. Due to the low weight of the sensors, the height h 3 at which the latter are placed can be greater than the height h 1 of the emission device 301.
- An aim of the invention being to position the sensors as high as possible in order to increase direct visibility and reduce the interference fringes due to reflections on the ground, this goal is therefore achieved thanks to the differentiated treatment of the emission device and of the receiving device.
- the sensors 31 1 to 315 of the receiving device comprise omnidirectional radiating elements in the vertical plane, such as for example dipole antennas mounted horizontally. The sensors can also be directional if the purpose of the antenna is not to provide 360 ° surveillance in the vertical plane.
- each sensor further comprises a low noise amplifier making it possible to raise the level of the signal before its transmission to the radar processing device 330.
- the transmission device 301 When the cable providing the connection between the transmission device 301 and the radar processing device carries a digital signal, the transmission device 301 comprises a digital to analog converter. Likewise, when the cable 320 providing the link between the sensors 31 1 to 315 of the receiving device and the radar processing device 330 carries a digital signal, the sensors each include an analog to digital converter.
- the radar processing device comprises the reverse converters.
- the link connecting the sensors of the reception device to the radar processing device is an optical link.
- the use of optical fiber makes it possible to reduce the section and the mass of the cable 320.
- This solution is preferable to the use of a copper cable because it still makes it possible to lighten the device, and to position the sensors of the cable. receiving antenna as high as possible. It also makes it possible to facilitate the deployment / folding of the receiving device.
- the sensors of the receiving device each have converters of the received signals, analog or digital, to optical signals, to transmit the signals acquired by the radiating elements to the radar processing device, as well as, when they include a low noise amplifier, a converter of optical energy supplied by the radar processing device 330 to electric energy to supply it.
- the radar processing device 330 comprises the
- the detection of objects and the estimation of their azimuth are produced by the radar processing device 330 from the signals received from all of the sensors or a selection of at least two sensors, using the directivity properties of the array antenna thus formed.
- the choice of the number of sensors used may depend on the frequency band of the signal, the spacing between the sensors, as well as the desired directivity and gain performance.
- the multi-sensor antenna can be used as a directive array antenna scanning the horizontal plane, adjusting the phase and amplitude of the signals received from each of the sensors and recombining them to orient the antenna beam.
- the signals received from at least two sensors can be used by an interferometry method or by high resolution processing.
- the receiving device is deployed over a length
- the determination of their direction and distance in a vertical plane are carried out using the coloring properties of the signals emitted.
- This determination can be made from the signal received from only one of the sensors of the receiving device according to methods known to those skilled in the art, which has the advantage of being relatively inexpensive and inexpensive in terms of computing resources.
- the determination in the vertical plane can be made from the coloring properties of the signals received by a plurality of sensors, to benefit from a processing gain allowing to improve the performance of the detection.
- the detection can be carried out sequentially or
- the embodiment of FIG. 3 makes it possible to position the sensors of the receiving antenna higher than if the whole of the radar were to be raised.
- it has the defect of presenting an ambiguity concerning the front / rear position of the objects detected in the horizontal plane when the radiating elements of the sensors of the receiving antenna are omnidirectional in this plane, that is to say that the position is determined within plus or minus p because the antenna pattern is symmetrical with respect to the axis of the receiving antenna.
- This defect does not appear in the first embodiment where the azimuth of the targets is identified by virtue of the coloring properties of the signal and not by using the directivity properties of the reception antenna formed by the various reception sensors.
- means making it possible to make the antenna beam directional can be deployed, such as for example a reflective plane or a dielectric insulator arranged in 'one side of the antenna to block and reflect or attenuate the beam in one half of the horizontal plane.
- a reflective plane or a dielectric insulator arranged in 'one side of the antenna to block and reflect or attenuate the beam in one half of the horizontal plane.
- Figure 4 shows a third embodiment of a system
- the sensors 41 1 to 416 of the receiving device are no longer arranged in line but are arranged so as to form a triangle or any other geometric shape making it possible to lift the ambiguity on the direction of arrival forward / backward in the horizontal plane.
- one possible implementation consists in estimating the direction of arrival in the horizontal plane from the following triplets of sensors: (41 1, 412, 413), (413, 414, 415), and (415, 416, 411), then using the ambiguous position information detected by each triplet to resolve the ambiguity on the arrival position in the vertical plane.
- this determination entails a loss in the gain of the antenna compared to the embodiment of FIG. 3.
- the operation of the third embodiment resumes that of the second mode of operation:
- the emission device 301 emits signals in a colored manner in the vertical plane
- the azimuth of the detected objects is determined by independently considering each of the branches of the triangle formed by the sensors, then by comparing the results to resolve the ambiguity on the direction of the detected objects,
- the elevation of the detected objects is determined from the signals received from one or more sensors by considering the color of the signals emitted by the transmitting device. This measurement can be confirmed, if necessary, from signals received from one or more other sensors.
- the treatments in the horizontal plane and the vertical plane can be carried out sequentially or simultaneously, so as to benefit from a gain in processing.
- optical fiber for the transmission of signals acquired by
- various sensors further lighten the receiving device.
- the use of a method of coloring the radar signals emitted in the vertical plane makes it possible to determine the direction of the objects detected in this plane from the signals received from the same sensors as in the horizontal plane, and therefore of dramatically decrease the number of sensors required to provide three-dimensional detection.
- the cost of the antenna and its deployment complexity are reduced, and the sensors can be installed at great heights, thus improving the reception conditions.
- the various embodiments of a detection system according to the invention are particularly suitable for the three-dimensional monitoring of theaters of operation.
- the operating frequency of the detection system can be adapted very simply, by selecting a set of sensors among the sensors of the receiving antenna according to their distances and the desired wavelength. Since the radar processing device is able to select the sensors from which the detection processing operations are carried out, the reception antenna can comprise heterogeneous sensors adapted to operate at different frequencies, which confers a multi-frequency capacity which reinforces the multi-role aspect of the device.
- the radar processing device according to the invention is multi-role
- a reception antenna comprising a plurality of sensors arranged in a plane perpendicular to the foreground, each sensor comprising a radiating element omnidirectional or not in the foreground,
- Figures 5a and 5b show the losses associated with the interference fringes, for equipment located at ground level ( Figure 5a) and for equipment placed at a height of 50 meters ( Figure 5b).
- the different fill textures designate the loss levels associated with the interference fringes, depending on the altitude and distance from the target.
- the interference fringes are linked to the multiple reflections of the signals during its propagation, and to the way in which these paths recombine.
- the system according to the invention in which the device for receiving the radar signals can be raised at a lower cost, indeed has the effect of significantly reducing the interference fringes undergone by the signals, and therefore of '' improve the performance of the device.
- the invention also relates to a method of implementing a
- the method comprises a step 601 of transmitting a signal according to a method of transmitting colored in a first plane, such as for example the horizontal plane for an implementation in a case of figure corresponding to figure 2, or the vertical plane for figures 3 and 4.
- the method comprises a step 602 of receiving signals from at
- sensors arranged in a second plane, perpendicular to the foreground.
- These sensors can include omnidirectional radiating elements in the foreground, for 360 ° coverage in that plane, or radiating elements covering only part of the foreground.
- the method comprises a step 603 of determining the presence of objects and estimating their direction and distance. This determination is carried out in the foreground by exploiting the coloring properties of the signal received by at least one of the sensors. It is carried out in the second plane by exploiting the signals received from at least two of the sensors of the receiving device, but the gain of the antenna will be all the greater as the number of sensors considered is large.
- the exploitation of the received signals can be done by implementing an interferometry method or high-resolution processing on the received signals.
- a directive array antenna can be formed from the various sensors. By varying the direction of the beam from this array antenna, it is possible to scan the space to locate the object in the second plane.
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- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Electromagnetism (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR1908060A FR3098923B1 (fr) | 2019-07-18 | 2019-07-18 | Systeme de detection d'objets longue portee |
PCT/EP2020/070322 WO2021009359A1 (fr) | 2019-07-18 | 2020-07-17 | Systéme de détection d'objets longue portée |
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EP3999872A1 true EP3999872A1 (fr) | 2022-05-25 |
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EP20740028.4A Pending EP3999872A1 (fr) | 2019-07-18 | 2020-07-17 | Systéme de détection d'objets longue portée |
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US (1) | US20220252711A1 (fr) |
EP (1) | EP3999872A1 (fr) |
FR (1) | FR3098923B1 (fr) |
WO (1) | WO2021009359A1 (fr) |
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US5955989A (en) * | 1990-11-15 | 1999-09-21 | Li; Ming-Chiang | Optimum edges for speakers and musical instruments |
JP4766405B2 (ja) * | 2008-11-14 | 2011-09-07 | トヨタ自動車株式会社 | レーダ装置 |
FR2950147B1 (fr) * | 2009-09-15 | 2012-07-13 | Thales Sa | Radar a agilite de faisceau, notamment pour la fonction de detection et d'evitement d'obstacles |
DE102011083756A1 (de) * | 2011-09-29 | 2013-04-04 | Siemens Ag | Radar-Vorrichtung und Verfahren zum Erzeugen einer Gruppencharakteristik eines Radars |
EP3169974A2 (fr) * | 2014-07-18 | 2017-05-24 | Altec S.p.A. | Plateforme de capture d'images et/ou de signaux radio |
DE102017114223A1 (de) * | 2017-06-27 | 2018-12-27 | Gottfried Wilhelm Leibniz Universität Hannover | Nahfeld-Radareinrichtung, Land-, Luft- oder Wasser-Fahrzeug, Verwendung einer Radareinrichtung, Verfahren zum Betrieb einer Radareinrichtung sowie Computerprogramm |
-
2019
- 2019-07-18 FR FR1908060A patent/FR3098923B1/fr active Active
-
2020
- 2020-07-17 WO PCT/EP2020/070322 patent/WO2021009359A1/fr active Application Filing
- 2020-07-17 US US17/627,094 patent/US20220252711A1/en active Pending
- 2020-07-17 EP EP20740028.4A patent/EP3999872A1/fr active Pending
Also Published As
Publication number | Publication date |
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FR3098923A1 (fr) | 2021-01-22 |
FR3098923B1 (fr) | 2021-07-30 |
WO2021009359A1 (fr) | 2021-01-21 |
US20220252711A1 (en) | 2022-08-11 |
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