Radar system and procedure for configuring a radar system

Abstract

Radar system (110), comprising: two or more nodes (210a, 210b, 210c, 210d), each node (210a, 210b, 210c, 210d) comprising one or more transmitting antennas (220a) and one or more receiving antennas (220b, 220c, 220d); and a processor (240) configured to receive signals at each of the two or more nodes (210a, 210b, 210c, 210d), to estimate an angle of incidence (θ) of each target (140) identified based on the received signals, to estimate an offset (230) of each of the two or more nodes (210a, 210b, 210c, 210d) from a known position, and to compensate for the offsets (230) when estimating the angle of incidence (θ) for subsequent targets (140) in the received signals; wherein the processor (240) is further configured to identify point targets among the identified targets (140) based on the received signals and to estimate the offset value of each of the two or more nodes (210a, 210b, 210c, 210d) from the known location based on the point targets; wherein the processor (240) is further configured to use offset hypotheses to generate a synthetic arrangement response corresponding to the estimation of the angle of incidence (θ) for each point target among the targets (140) identified on the basis of the received signals.

Description

Technical field

[0001] The subject of the disclosure relates to the estimation and compensation of transceiver position offsets in a radar system for targets in unknown positions. Introduction

[0002] Vehicles (e.g., automobiles, trucks, construction equipment, agricultural machinery, automated manufacturing plants) increasingly use sensors to detect objects in their environment. This detection can be used to enhance or automate vehicle operation. Examples of sensors include cameras, light detection and ranging (Lidar) systems, and radio detection and ranging (Radar) systems. A radar system can include multiple transmitters / receivers, which are nodes containing one or more transmitting antennas and one or more receiving antennas. The multiple transmitters / receivers facilitate high angular resolution when the node positions are known. However, node positions can vary because the radar system's performance changes over time due to many factors, such as temperature, vibration, and mounting forces.In a calibration or test environment with a known target position, the offsets from the original node positions can be determined. However, during normal operation of a radar system (e.g., a radar system in a vehicle), the target positions are unknown, and this calibration process is not possible.

[0003] CN 104181513 A describes a method for correcting the position of array elements of a radar antenna, which relates to the field of array signal processing. The method comprises the following steps: 1) A model matrix of echo signals is created, an autocorrelation matrix of the echo signals is solved, and the position coordinates of N array elements are determined. 2) The arrival angle of an object is estimated, and a matrix consisting of characteristic vectors corresponding to the characteristic values ​​of a correlation matrix of the arrival angles is solved. 3) A perturbation matrix of the array elements is estimated. 4) A position perturbation matrix of the array elements is calculated. 5) The position coordinates of the array elements are calculated.

[0004] Accordingly, the object of the invention is to provide an estimation and compensation of transceiver position offsets in a radar system for targets in unknown positions. Description of the invention

[0005] The invention is defined by the claims.

[0006] According to a first aspect of the invention, a radar system comprises two or more nodes. Each node comprises one or more transmitting antennas and one or more receiving antennas. The radar system also comprises a processor for receiving signals at each of the two or more nodes, estimating the angle of incidence of each target identified based on the received signals, estimating the offset of each of the two or more nodes from a known position, and compensating for the offsets when estimating the angle of incidence for subsequent targets in the received signals.

[0007] In addition to one or more of the features described herein, the processor can estimate the angle of incidence based on a beamforming method that specifies the amplitude at each azimuth angle in a field of view of the radar system.

[0008] According to the first aspect of the invention, the processor identifies point targets between the identified targets based on the received signals and the processor estimates the offset value of each of the two or more nodes from the known location based on the point targets.

[0009] According to the first aspect of the invention, the processor uses offset hypotheses to generate a synthetic arrangement response that corresponds to the estimation of the angle of incidence for each point target among the targets identified based on the received signals.

[0010] In addition to one or more of the features described herein, the processor can determine a best-match offset hypothesis between the offset hypotheses, providing the best match between the synthetic array response and a measured array response according to the received signals.

[0011] In addition to one or more of the features described herein, the processor can average the best-match offset hypothesis associated with each point target to estimate the offset of each of the two or more nodes from the known location.

[0012] In addition to one or more of the features described herein, the system may be located in a vehicle.

[0013] In addition to one or more of the features described here, the system can be part of a vehicle and the estimation of the object's location is used to improve or automate vehicle operation.

[0014] According to a second aspect of the invention, a method for configuring a radar system includes transmitting signals from one or more transmitting antennas at each of two or more nodes and receiving the received signals at one or more receiving antennas at each of the two or more nodes. The method also includes estimating the angle of incidence of each target identified based on the received signals, estimating the offset of each of the two or more nodes from a known position, and compensating for the offsets when estimating the angle of incidence for subsequent targets in the received signals.

[0015] In addition to one or more of the features described herein, estimating the angle of incidence can be based on a beamforming method that specifies the amplitude at each azimuth angle in a field of view of the radar system.

[0016] According to the second aspect of the invention, estimating the offset of each of the two or more nodes from the known location involves identifying point targets between the identified targets based on the received signals and using offset hypotheses to generate a synthetic arrangement response that corresponds to estimating the angle of incidence for each point target among the identified targets based on the received signals.

[0017] In addition to one or more of the features described herein, the procedure can also determine a best-match offset hypothesis between the offset hypotheses, providing a best match between the synthetic array response and a measured array response according to the received signals, and average the best-match offset hypothesis assigned to each point target to estimate the offset of each of the two or more nodes from the known location.

[0018] In yet another exemplary embodiment, a vehicle includes a radar system comprising two or more nodes. Each node includes one or more transmitting antennas and one or more receiving antennas. The radar system also includes a processor to receive signals at each of the two or more nodes, estimate the angle of incidence of each target identified based on the received signals, estimate the offset of each of the two or more nodes from a known position, and compensate for the offsets when estimating the angle of incidence for subsequent targets in the received signals. The vehicle also includes a vehicle control system to enhance or automate vehicle operation based on the object's location.

[0019] In addition to one or more of the features described herein, the processor estimates the angle of incidence based on a beamforming method that specifies the amplitude at each azimuth angle in a field of view of the radar system.

[0020] In addition to one or more of the features described herein, the processor identifies point targets between the identified targets based on the received signals.

[0021] In addition to one or more of the features described herein, the processor estimates the offset value of each of the two or more nodes from the known location based on the point targets.

[0022] In addition to one or more of the features described herein, the processor uses offtheses to generate a synthetic arrangement response that corresponds to the estimation of the angle of incidence for each point target among the targets identified based on the received signals.

[0023] In addition to one or more of the features described herein, the processor determines the best-match offset hypothesis between the offset hypotheses that provides the best match between the synthetic array response and a measured array response according to the received signals.

[0024] In addition to one or more of the features described herein, the processor averages the best-match offset hypothesis associated with each point target to estimate the offset of each of the two or more nodes from the known location.

[0025] The aforementioned properties and advantages, as well as other features and functions of the present disclosure, will become readily apparent from the following detailed description in conjunction with the accompanying drawings. Brief description of the drawings

[0026] Other features, advantages, and details appear, only as examples, in the following detailed description, which refers to the following drawings: Fig. 1 is a block diagram of a scenario concerning a radar system according to one or more embodiments; Fig. 2 is a block diagram of the radar system according to one or more embodiments; Fig. 3 is a process flow of a method for estimating and compensating offsets in the positions of transceiver nodes in a radar system according to one or more embodiments. Detailed description

[0027] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or its use. It should be understood that in the drawings, corresponding reference numerals denote identical or corresponding parts and features.

[0028] In a radar system, a transmitter emits energy, and if one or more targets are within the radar system's field of view, the targets reflect a portion of the energy, which the radar system can detect as a received signal. A radar system can include multiple transmitting elements and multiple receiving elements. Processing the received signals provides information about the target, such as range, Doppler, azimuth, altitude, and amplitude. The angle of incidence can be estimated based on a known beamforming technique. Digital beamforming involves obtaining a vector of complex scalars from the vector of received signals and the matrix of actual received signals at each receiving element for each angle of incidence of a target reflection. Digital beamforming represents an azimuth angle (i.e., the angle of incidence of the target's reflection).The beamforming result (the angle of incidence) to each of the detected targets is prepared based on a threshold of the complex scalars of the obtained vector. The beamforming result can be displayed as the azimuth angle along one axis and the amplitude along the other axis in a two-dimensional diagram. The main lobe (i.e., the angle with the highest amplitude) indicates the angle of incidence of the target. Other, lower amplitudes are called side lobes.

[0029] As previously mentioned, multiple transmitter-receivers, or nodes, in a radar system allow for determining a target's position with higher angular resolution than a single node. However, offsets in the nodes' positions from their original locations, which develop during operation due to factors such as temperature and vibration, reduce the accuracy of the angle-of-incidence estimates. Determining these offsets to compensate for them and improve target angle estimation typically requires using a target at a known location to calibrate the node positions. However, a calibration procedure requiring a target at a known location is challenging to perform during operation (e.g., while the radar system is operating in a vehicle).Embodiments of the systems and methods described in detail herein relate to the estimation and compensation of transceiver position offsets in a radar system for targets in unknown positions. In particular, for each node of the radar system, the node offset and the node position offset are estimated using a method that includes the collection of data for point targets.

[0030] According to an exemplary embodiment, Fig. 1. A block diagram of a scenario involving a coherent radar system 110. The one in Fig. The vehicle 100 shown is a motor vehicle 101. A coherent radar system 110, which, with reference to Fig. The radar system 110, which is described in more detail in Figure 2, is shown under the hood of the motor vehicle 101. According to alternative or additional embodiments, one or more radar systems 110 may be located elsewhere in the vehicle 100. Another sensor 115 (e.g., camera, sonar, lidar system) is also shown. Information obtained by the radar system 110 and one or more other sensors 115 can be provided to a controller 120 (e.g., electronic control unit (ECU)) for image or data processing, target recognition, and subsequent vehicle control.

[0031] The controller 120 can use the information to control one or more vehicle systems 130. In an exemplary embodiment, the vehicle 100 can be an autonomous vehicle, and the controller 120 can perform known vehicle operation control operations using information from the radar system 110 and other sources. In alternative embodiments, the controller 120 can extend vehicle operation using information from the radar system 110 and other sources as part of a known system (e.g., collision avoidance system, adaptive cruise control system). The radar system 110 and one or more other sensors 115 can be used to detect objects 140, such as the pedestrian 145, who is in Fig. Figure 1 is shown. The controller 120 can include a processing circuit that may contain an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0032] Fig. Figure 2 is a block diagram of the radar system 110 according to one or more embodiments. For the exemplary radar system 110, four nodes 210a, 210b, 210c, 210d (generally referred to as 210) are shown. Node 210a, for example, includes four antennas 220a, 220b, 220c, 220d (generally referred to as 220). Antenna 220a can transmit, while antennas 220b, 220c, 220d receive. The in Fig. The exemplary configuration shown in Figure 2 is not intended to limit the number of nodes 210, the number of antennas 220, or the number of antennas 220 transmitted or received at any given node 210 of the radar system 110, which is processed according to one or more embodiments. The processing of the received signals may be performed by a processor 240, which is part of the radar system 110. According to alternative or additional embodiments, the processing may be performed by the controller 120. The processor 240 may include a processing circuit similar to that discussed for the controller 120. The offsets 230a, 230b, 230c, 230d (generally 230) indicate exemplary offsets 230 experienced by the exemplary nodes 210 from their original (known) positions. The offsets 230 include a rotation from the original location as well as a change in position.

[0033] A target 140, whose position is unknown, is in Fig. Figure 2 shows the angle of incidence θ of target 140 with respect to the center of the node array 210. The accuracy of the angle of incidence θ, as estimated by the radar system 110, is affected by the offsets 230, necessitating estimation and compensation according to one or more embodiments. If the position of the nodes 210 is known, the result of beamforming on the reflections received from the nodes 210 is a narrow main lobe at the angle of incidence θ and low-side lobe levels relative to the main lobe. The offsets 230 lead to higher lobe levels. While this may have little effect on the result of a scenario involving a single target 140, the higher side lobes result in data relating to targets 140 interfering with each other in a multi-row scenario.

[0034] Fig. Section 3 describes a process flow of a method 300 for estimating and compensating for offsets 230 in the positions of transceiver nodes 210 in a radar system 110 according to one or more embodiments. In section 310, obtaining point targets involves identifying targets 140 as point targets based on beamforming results. That is, during normal operation of the radar system 110, if the beamforming result (specifying angle versus amplitude) includes a single main lobe, then the associated target 140 is considered a point target. Estimating the angle of incidence θ of each point target in section 320 involves using the beamforming process result to identify the angle associated with the highest amplitude.

[0035] In Block 330, the processes involve generating a synthetic array response based on the estimated angle of incidence θ and using offset hypotheses. For each hypothesis regarding the offsets 230 of the nodes 210, the estimated angle of incidence θ is used to generate the synthetic array response of the nodes 210. In Block 340, the synthetic response corresponding to each offset 230 hypothesis is compared to the actual measured array response. The processes involve determining the hypothesis of offsets 230 for which the synthetic array response (from Block 330) best matches the measured array response. This determination is averaged over a number M of point targets (e.g., on a sequence of one thousand point targets).

[0036] In particular, according to an exemplary embodiment, the following optimization (i.e. minimization) can be used: θ^(1),..,θ^(N),δ^(N)=argminθ(1)…,θ(N),δ(1)…,δ(N)∑m=0M−1∑n=1N∑t=1T∑r=1R‖X‖22 X=St,r(n,m)−αe2πjΔt,r(n,m)(θ(n),δ(n),δtargetm)

[0037] As mentioned previously, M represents the number of point targets being averaged (i.e., m is the point target index). Additionally, N is the number of nodes 210 (i.e., n is the node index), T is the number of antennas 220 per node 210 used for transmitting (i.e., t is the transmit antenna index), and R is the number of antennas 220 per node 210 used for receiving (i.e., r is the receive antenna index). θ̂ (n) δ̂ is the rotational aspect of the offset 230 for a given node 210 n, which is a vector of three angles (yaw rate, pitch, inclination). (n) The positional offset 230 for the given node 210 n is given. S indicates the measured signal, α is a gain factor that needs to be optimized. θ (n) and δ (n)are a hypothesis of rotation and positional displacement 230 for the given node 210 n, and targetm is the estimated position of target 140 (point target) according to the beamforming result. If a small percentage of the targets 140 considered and used as point targets are actually multiple or distributed targets, those in Fig. The 3 estimation and compensation methods shown are still practical.

[0038] As previously mentioned for block 340 and as indicated by the equations, the hypothesis of the offsets 230 for which the synthetic array response agrees with the measured array response is considered the best estimate of the offsets 230 of the nodes 210. The resulting offsets 230 for the nodes 210 are used in the beam alignment adjustment at block 350. That is, at block 350, the processes involve compensating for the estimated offset 230 for each node 210 (at block 340) in the beam alignment used with subsequent received signals. The in Fig.The three processes shown can be repeated continuously, periodically, or based on an event (e.g., by monitoring the beamforming result to detect a change in offsets 230). The number of point targets averaged at block 340 can be fixed, based on a duration (e.g., average point targets acquired over one hour), or determined on another basis (e.g., by monitoring the beamforming result to detect a change in offsets 230).

Claims

[1] Radar system (110), comprising: two or more nodes (210a, 210b, 210c, 210d), each node (210a, 210b, 210c, 210d) comprising one or more transmitting antennas (220a) and one or more receiving antennas (220b, 220c, 220d); and a processor (240) configured to receive signals at each of the two or more nodes (210a, 210b, 210c, 210d), to estimate an angle of incidence (θ) of each target (140) identified based on the received signals, to estimate an offset (230) of each of the two or more nodes (210a, 210b, 210c, 210d) from a known position, and to compensate for the offsets (230) when estimating the angle of incidence (θ) for subsequent targets (140) in the received signals; wherein the processor (240) is further configured to identify point targets among the identified targets (140) based on the received signals and to estimate the offset value of each of the two or more nodes (210a, 210b, 210c, 210d) from the known location based on the point targets; wherein the processor (240) is further configured to use offset hypotheses to generate a synthetic arrangement response corresponding to the estimation of the angle of incidence (θ) for each point target among the targets (140) identified on the basis of the received signals. [2] Radar system (110) according to claim 1, wherein the processor (240) is further configured to estimate the angle of incidence (θ) based on a beam shaping method that specifies the amplitude at each azimuth angle in a field of view of the radar system (110). [3] Radar system (110) according to claim 1, wherein the processor (240) is further configured to determine a best-match offset hypothesis between the offset hypotheses that provide a best match between the synthetic array response and a measured array response according to the received signals, and the processor (240) is further configured to average the best-match offset hypothesis associated with each point target in order to estimate the offset of each of the two or more nodes (210a, 210b, 210c, 210d) from the known location. [4] Radar system (110) according to claim 1, wherein the radar system (110) is located in a vehicle (100, 101) and the angle of incidence (θ) is used to extend or automate the operation of the vehicle (100, 101). [5] Method (300) for configuring a radar system (110), comprising the method (300): the transmission from one or more transmitting antennas (220a) from each of two or more nodes (210a, 210b, 210c, 210d); the reception of received signals at one or more receiving antennas (220b, 220c, 220d) from each of the two or more nodes (210a, 210b, 210c, 210d); the estimation, using a processor (240), of an angle of incidence (θ) of each target (140) which is identified based on the received signals; estimating an offset (230) of each of the two or more nodes (210a, 210b, 210c, 210d) from a known location using the processor (240); and the compensation, using the processor (240), for the offsets (230) when estimating the angle of incidence (θ) for subsequent targets (140) in the received signals; wherein estimating the offset (230) of each of the two or more nodes (210a, 210b, 210c, 210d) from the known location involves identifying point targets between the identified targets (140) based on the received signals and using offset hypotheses to generate a synthetic arrangement response equivalent to estimating the angle of incidence (θ) for each point target among the identified targets (140) based on the received signals. [6] Method (300) according to claim 5, wherein the estimation of the angle of incidence (θ) is based on a beam shaping method which specifies the amplitude at each azimuth angle in a field of view of the radar system (110). [7] Method (300) according to claim 5, further comprising determining a best-match offset hypothesis between the offset hypotheses that provide a best match between the synthetic array response and a measured array response according to the received signals, and averaging the best-match offset hypothesis assigned to each point target to estimate the offset of each of the two or more nodes (210a, 210b, 210c, 210d) from the known location.

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