Use of a radar sensor equipped with a waveguide antenna array for a method of determining a self-speed estimated value and a target angle estimated value

Abstract

The present invention relates to the use of a radar sensor comprising a waveguide antenna array having at least two groups of antenna units each comprising a plurality of antenna elements, wherein the antenna elements within each antenna unit are arranged side by side in a first direction, and in a first group (104) the antenna units are arranged offset from each other in a second direction perpendicular to the first direction, and in a second group the antenna units are arranged offset from each other in the first direction, and to a method for determining an estimated own velocity and an estimated angle of a target, the method having the following steps: The distances between the radar sensor with synthetic aperture and the respective targets are measured by the radar sensor with synthetic aperture. In addition, the relative velocities of the respective targets are measured by the radar sensor with synthetic aperture using the Doppler effect. An angle estimation of an angle estimation value characterizing the angle between the direction of the own velocity of the radar sensor with synthetic aperture and the respective targets is performed. Thereafter, for each target, an individual estimated own velocity (Equation A) of the radar sensor with synthetic aperture is determined using the relative velocity and the angle estimation value. Classification and grouping are performed with respect to stationary targets for which the individual estimated own velocities (Equation A) are together within a settable range (B) of the individual estimated own velocities, and moving targets for which the individual estimated own velocities (Equation A) are outside the range (B). For the stationary targets, a combined estimated own velocity is determined from the individual estimated own velocities (Equation A) of the stationary targets. Finally, a corrected angle estimation value for the stationary targets is determined using the combined estimated own velocity and the respective measured relative velocities.

Description

Technical Field

[0001] The present invention relates to the field of radar sensor devices, and more particularly to the field of Multiple-Input-Multiple-Output (MIMO) and Synthetic Aperture (SAR) radars.

Background Art

[0002] Radar systems for measuring the distance, relative speed, and angle of an object are increasingly being used in automobiles for safety and comfort functions. Today, in particular, Multiple-Input-Multiple-Output (MIMO) radars, i.e., radars having a plurality of transmission paths for transmitting and receiving radar signals, are used for this purpose. Recently, Synthetic Aperture (SAR) radars have become known. The principle of synthetic aperture enables particularly accurate angle measurement when the radar sensor moves itself. Synthetic aperture utilizes the fact that, based on the self-movement of the radar sensor, the transmitting antenna and the receiving antenna are at different spatial positions at each measurement point. In this case, the measurement is processed with a synthetic antenna aperture. During evaluation, this can be regarded as equivalent to a large antenna aperture along the travel trajectory. Thereby, a large synthetic aperture is achieved that would be impractical or completely impossible with a real antenna aperture because a large number of antenna elements are required. With SAR, a higher resolution than that of a real antenna aperture is possible in angle measurement.

[0003] In order to evaluate the measured radar signal as a synthetic aperture, it is usually assumed that the surroundings of the radar are stationary. In addition to this, the self-movement of the radar sensor and thus the positions at which the individual measurements are taken must be known. This trajectory of the radar is incorporated into the SAR evaluation algorithm and is the basis for calculating the SAR image. Depending on the evaluation algorithm, an estimated self-speed may be sufficient to calculate the SAR image instead of a more accurate trajectory. In this case, the trajectory is typically assumed to be linear, and more complex trajectories cannot be depicted.

[0004] Today's radar systems in the automotive field generally use frequency-modulated continuous-wave radar (FMCW) with a ramp that rises at a high speed, so-called Fast-Chirp-Modulation. In this case, a plurality of successive linear frequency ramps with the same slope gradient are implemented. The mixing of the transmitted signal and the received signal at each time produces a low-frequency signal (referred to as the beat frequency), and the frequency of this low-frequency signal is proportional to the distance. This system is generally designed so that the component caused by the Doppler frequency in the beat frequency can be ignored. The acquired distance information is sufficiently unambiguous. In addition to this, by observing the time evolution of the phase of the complex distance signal across the ramp, the Doppler shift can be determined, and based on this, the relative speed can be determined. The determination of the distance and the determination of the relative speed are performed independently of each other. Generally, a two-dimensional Fourier transform is used for this purpose.

[0005] Conventional SAR evaluation assumes stationary targets. Moving targets that do not meet this assumption are incorrectly, angularly shifted, and blurred in the SAR image. However, in automobiles, moving targets are also a matter of concern (for example, to avoid collisions with such moving targets). To estimate the self-trajectory or self-speed of a radar sensor, two approaches are known. One is to use an external sensor, such as an inertial measurement unit (IMU) or an odometry sensor. The other is to use a very computationally complex autofocus algorithm, which is not applicable to real-time processing. Summary of the Invention Problems to be Solved by the Invention

[0006] The object of the present invention is the use of a radar sensor equipped with a waveguide antenna array, which will be described in detail below, for a method of determining an estimated self-speed and estimated angles of a plurality of surrounding targets, and the process steps of the determination method will be described in more detail below. Means for Solving the Problems

[0007] The waveguide antenna array of the radar sensor has at least two groups of antenna units, and the antenna elements in each antenna unit are arranged side by side in a first direction. In the first group, the antenna units are arranged shifted from each other in a second direction perpendicular to the first direction. In the second group, the antenna units are arranged shifted from each other in the first direction. Thereby, a Multiple-Input-Multiple-Output (MIMO) radar sensor is provided.

[0008] This radar sensor utilizes Digital Beamforming (DBF), and thus the antenna elements of one antenna unit can record and evaluate one radar signal together. The first group with these antenna units in the second direction is preferably used for azimuth measurement, and the second group with these antenna units in the first direction is preferably used for elevation measurement.

[0009] In the second group, it may be contemplated to arrange the antenna units shifted from each other only in the first direction. This reduces the computational cost during digital beamforming. Optionally, in the second group, the antenna units can additionally be arranged shifted from each other in the second direction. Thereby, measurement in the second direction is enabled for the second group, and this radar sensor is designed based on Multiple-Input-Multiple-Output (MIMO).

[0010] The array groups are preferably assigned alternately to the transmitting side or the receiving side. Based on the MIMO principle, the transmitting antenna and the receiving antenna are in principle interchangeable. Hereinafter, stationary targets (also referred to as static targets) and moving targets (also referred to as dynamic targets) are distinguished. Stationary targets are objects that do not move themselves in the surroundings, that is, for example, buildings, trees, infrastructure, etc. on and beside the road. Moving targets are moving objects in the surroundings, that is, for example, other vehicles, pedestrians, other road users, etc.

[0011] The radar sensor moves and during this movement transmits a number of measurement signals and receives the signals reflected by the targets. Thus, this radar sensor is a synthetic aperture radar sensor. From the transmitted and received signals, the relative speed is determined for each target. To determine the relative speed, the Doppler effect in the measurement signals is evaluated, in particular the Doppler shift is determined. In addition to this, the distance between the radar sensor and the targets is likewise determined from the transmitted and received signals. This can be done, for example, via Fourier processing. To recognize the targets during the measurement, detection is carried out using a constant false alarm rate (CFAR).

[0012] Subsequently, a rough angle estimation is carried out. In this regard, for each target, an angle estimation value is estimated which characterizes the direction of the own speed of the radar sensor, i.e. the direction in which the radar sensor moves (“forward direction”), and the target angle between the radar sensor and each respective target. The angle estimation can be carried out, for example, by digital beamforming. For this purpose, the radar sensor has at least one additional receiving channel and / or at least one additional transmitting channel. It is preferable that the angle estimation value directly presents the target angle. However, the target angle may also be indirectly revealed from the conversion of the angle estimation value or a mathematical relationship. Since the angle estimation value is still further processed later, this angle estimation may clearly be less accurate compared to conventional angle measurements.

[0013] By inverse projection, for each target separately, an individual ego - velocity estimate of the radar sensor is calculated using the relative velocity and angle estimates. That is, for each target, the measured or estimated values are used to obtain the individual ego - velocity estimate of the radar sensor based on them. Thus, typically, a number of individual ego - velocity estimates that depend on the velocity of the target are determined. For stationary targets, since the relative velocity between the target and the radar sensor is proportional to the ego - velocity of the radar sensor and the target angle, these individual ego - velocity estimates are grouped closely together. However, for moving targets, since the relative velocity depends not only on the ego - velocity of the radar sensor and the target angle but also on the velocity of the target, these individual ego - velocity estimates are more widely separated from each other. In addition to this, in a typical situation, there are clearly more stationary targets than moving targets with the same relative velocity to the radar sensor in the surroundings, and moving targets usually have different velocities from each other.

[0014] This enables, among other things, the classification and grouping of the individual ego - velocity estimates by clustering. For this purpose, a range is defined for the individual ego - velocity estimates that enables the discrimination between stationary and moving targets. The individual ego - velocity estimates that exist together within the configurable range are assigned to stationary targets. The individual ego - velocity estimates outside this range are assigned to moving targets. Thereby, moving targets can be identified (MTI - Moving Target Indication). Each calculated individual ego - velocity estimate can be recorded, for example, in a histogram for classification.

[0015] The individual self - speed estimates are then evaluated separately according to the assignment. For stationary targets, the combined self - speed estimate is determined from the individual self - speed estimates assigned to the stationary target. Since this combined self - speed estimate is calculated from stationary targets only (autofocus), it can be regarded as the actual self - speed of the radar sensor. In addition, for stationary targets, a corrected angle estimate is calculated using the combined self - speed estimate and each measured relative speed. This corrected angle estimate can be regarded as the actual angle of the target relative to the radar sensor.

[0016] This method further enables the determination of self - speed estimates and angle estimates directly from the measurements without the need for additional sensors such as, for example, an IMU or an odometry sensor. Typically, odometry sensors used in vehicles are often placed too far away from the radar sensor and, in addition, perform too few measurements per time interval.

[0017] By using a radar sensor with a waveguide antenna array for the method described above, the waveguide antennas are combined with the concepts of MIMO and SAR. In this case, the same antenna unit or antenna element is used for both MIMO and SAR. As a result, the number of channels of the radar sensor can be reduced, and thus the antenna area can be minimized. Especially in the case of waveguide antennas, due to their three - dimensional structure, they typically require a large installation space and involve labor - intensive manufacturing, so the reduction of channels is a great advantage.

[0018] By using waveguide antennas, a high degree of freedom is achieved in the arrangement of the antenna array elements. Thereby, the advantageous λ / 2 arrangement of the antenna unit can be easily achieved, and this λ / 2 arrangement is advantageous both for dynamics and for unambiguous angle estimation.

[0019] For the received, downconverted and baseband sampled radar signal of the antenna array to be compatible with the combination of MIMO and SAR, it must be possible to uniquely sample the Doppler frequency. The range in which the radial component of the relative velocity can be uniquely captured v rel,r,u for,

[0020]

number

[0021] applies. In the formula, v rel,r,max and v rel,r,min is the upper or lower limit of this range. D,u represents the bandwidth of the Doppler frequency that can be captured univocally to the maximum extent, c is the wave propagation speed, f c is the carrier frequency of the radar signal, and T ctc represents the period between two frequency ramps (chirp-to-chirp) of the same transmit antenna.

[0022] In time division multiplexing, for a fixed bandwidth and a fixed ramp slope or duration, the period T between two frequency ramps is ctc Since grows with the number of transmitters, the number of transmitters is limited in conventional FMCW-MIMO radar sensors based on time division multiplexing.,In the present invention, multiplexing in frequency dimension (FDM, Frequency Division Multiplexing) or multiplexing in code dimension (CDM, Code Division Multiplexing) is preferably implemented.,In this case, SAR does not have such limitations on the number of transmitters.

[0023] Advantageously, the configurable range used for the classification and grouping of the individual self-speed estimates is the measurement error tolerance range. This error tolerance range is determined from the error of the relative speed measurement and the error of the angle estimation. This ensures that the grouping is performed uniquely within the measurement error tolerance range, thus providing the maximum possible selectivity.

[0024] To determine the combined self - speed estimate, an averaged speed value of the individual self - speed estimates can be calculated. In this regard, classical averaging, such as arithmetic mean, weighted averaging depending on a weight that depends on the signal - to - noise ratio, determination of the maximum value within a histogram, generation of the median, etc. can be performed.

[0025] For the moving target as well, it is preferable to determine the respective angle estimate and the respective speed estimate. However, since the speed of the moving target is unknown, the above - mentioned evaluation will result in an incorrect angle estimate. As the angle estimate for each moving target, the angle estimate found during the above - mentioned angle estimation for that moving target itself can be used. Thereby, although the improvement of the angle estimation is not achieved, incorrect angle estimations are avoided. Furthermore, the radial speed estimate for each moving target can be determined from the relative speed measured using the Doppler shift. For this purpose, the combined self - speed estimate determined above is assumed to be the self - speed of the radar and is weighted by the cosine of the target angle and subtracted from the relative speed.

[0026] The movement of the radar and the movement of the moving target are both assumed to be two - dimensional movements in a plane. However, the targets measured by the sensor can exist at different heights with respect to this plane. This can occur especially when only a part of an object is captured, for example. In this case, the elevation angle between this plane and the target can be determined for the target. It is preferable that this elevation angle is considered when determining the individual self - speed estimate of the radar sensor using the relative speed and the estimated angle for each target.

[0027] This radar sensor preferably functions as a frequency - modulated continuous - wave radar and is a chirp - sequence radar that transmits a chirp signal with a ramp that rises at a high speed. Thereby, the distance can be easily measured in a manner known per se. In addition, the Doppler effect, especially the Doppler shift, can be determined from the temporal evolution of the phase of the complex distance signal across the ramp, and thereby the relative speed can be measured.

[0028] For determining the relative speed using the Doppler effect, a method that is already known can be used. In this regard, Keystone processing based on the chirp Z transform (CZT) is preferred because this processing is particularly computationally efficient and can correct the migration effects that occur.

[0029] Exemplary embodiments of the present invention are shown in the drawings and will be described in detail in the following explanation.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5

Modes for Carrying Out the Invention

[0031] FIG. 1 shows a waveguide antenna 100 of a radar sensor S not further shown here. The waveguide antenna 100 has a waveguide antenna array composed of a plurality of antenna elements 101. A plurality of, in this example, 12 antenna elements 101 each are arranged in a row in the first direction R1 and together constitute one antenna unit 102 (one antenna unit is illustratively framed in FIG. 1). The first direction R1 corresponds to a vertical line in this example within the global reference coordinate system. The antenna elements 101 of one antenna unit 102 transmit and receive radar signals together. In FIG. 1, a phase center 103 is marked for each antenna unit 102. The antenna units 102 of the waveguide antenna array are divided into two groups 104, 105. The first group 104 includes, in this example, 8 antenna units 102, and these antenna units 102 each have 12 antenna elements 101 arranged in a row in the first direction R1. In the first group 104, the antenna units 102 are arranged shifted with respect to each other in the second direction R2. The second direction R2 corresponds to one of the horizontal lines in this example within the global reference coordinate system, and in this example, as shown in FIG. 2, the vehicle speed v ego of the vehicle F having the radar sensor S. Generally, the second direction R2 may be angled with respect to the vehicle speed v ego of the vehicle F. This simply rotates the antenna lobe. The second direction R2 is associated with azimuth angles α1, α2, α3, and the first group 104 of antenna units 102 serves for the measurement of the azimuth angles α1, α2, α3. The second group 105 includes, in this example, 3 antenna units 102, and these antenna units 102 also each have 12 antenna elements 101 arranged in a row in the first direction R1. In the second group 105, the antenna units 102 are arranged shifted from each other in both the first direction R1 and the second direction R2. The second group 105 of antenna units 102 has an elevation angle Φ iIt is useful for the measurement and for the measurement of the azimuth angles α1, α2, α3. In the state shown here, the first group 104 of the antenna unit 102 is assigned to the receiving side RX, and the second group 105 of the antenna unit 102 is assigned to the transmitting side TX. The radar signal received by the first group 104 is processed using digital beamforming. However, the assignment may be switched, whereby the first group 104 is assigned to the transmitting side TX and the second group 105 is assigned to the receiving side RX. Therefore, the waveguide antenna 100 is designed for MIMO. In other exemplary embodiments not shown, in the second group 105, the antenna units 102 can be arranged shifted from each other only in the first direction R1. Thereby, two-dimensional digital beamforming is simplified. The radar sensor S provided with the waveguide antenna 100 described or the waveguide antenna array described is used in the method described below.

[0032] FIG. 2 shows a schematic view of a traffic situation of a vehicle F having a radar sensor S provided with the above-described waveguide antenna 100 and a plurality of other vehicles represented as targets Z1 to Z3. It is typical that there are additional targets not shown here, such as buildings, road infrastructure, i.e., signboards, guardrails, and the like, or the road itself. The vehicle F, and thus also the radar sensor S, moves linearly at its own speed v ego along a straight line. From the radar sensor S, for each of the illustrated targets Z1, Z2, Z3, the azimuth angles α1, α2, α3 between the direction of its own speed v ego and the directions of the respective targets Z1, Z2, Z3 are shown. In addition, the relative speeds v rel,1 , v rel,2 , v rel,3 of each of the targets Z1, Z2, Z3 with respect to the radar sensor S are shown. If one of the targets, for example target Z1, is a stationary target, i.e., not moving, the relative speed v rel,1 of attribution is the own speed v of the radar sensor S egois given as a projection onto the azimuth angle α1 of attribution. The projections are shown in FIG. 1 for all three targets Z1, Z2, Z3. For a moving target moving at an unknown speed, for example in the case of target Z2, the speed of target Z2 is the relative speed v rel,2 which is part of, and the measured relative speed v rel,2 differs from this projection.

[0033] FIG. 3 shows a flow diagram of one exemplary embodiment of the method according to the invention. In this case, a large number of targets, comprehensively represented here by i, are examined. Measurement 1 is carried out during the movement of the vehicle F and the radar sensor S. Measurement 1 is carried out by frequency-modulated continuous-wave radar modulation (FMCW), in which a chirp signal with a linearly increasing and identical gradient frequency ramp at high speed is output at set time intervals. The reflected signal is recorded and processed as the received signal. The mixing of the transmitted signal and the received signal at that time produces a low-frequency beat signal, and the frequency of this beat signal is proportional to the distance of target i. Measurement 1 is carried out such that the Doppler effect or Doppler shift in the beat frequency can be ignored or taken into account in the evaluation.

[0034] Thereafter, Keystone processing 2 is executed. In this regard, an estimation of the Doppler shift or Doppler frequency is carried out by determining the temporal evolution of the phase of the complex measurement signal across the frequency ramp. In this case, for each estimated value, the corresponding linear distance change (migration) is corrected. Thereby, the relative speed for each target i

[0035]

Number

[0036] is determined. Subsequently, distance estimation is performed using a conventional Fourier process 3 from the time domain to the frequency domain, particularly the fast Fourier transform (FFT). The generated two-dimensional spectra (distance and relative velocity) for each individual transmit-receive channel combination are averaged 4 non-coherently. For this purpose, the absolute value of each of these spectra is generated, and then these absolute values or their absolute squares are summed. To recognize the target during measurement, detection 5 by constant false alarm rate (CFAR) is performed.

[0037] Furthermore, angle estimation 6 is performed, in which case the estimated azimuth value of the target

[0038]

Number

[0039] is determined. This estimated azimuth value

[0040]

Number

[0041] represents the azimuth angle between the measurement axis of the radar sensor S and the target i, and thus also reflects the mounting situation of the radar sensor S. Since the mounting situation is known, the estimated azimuth value

[0042]

Number

[0043] can be converted, by coordinate transformation, into an estimated value for the azimuth angle α ego between the direction of the own velocity v i and the direction of the target i. For the example shown in FIG. 2, the measurement axis is perpendicular to the direction of the own velocity v ego Thereby, the following relationship exists: θ i = 90 - α iDigital beamforming is used for angle estimation 6. In this case, simultaneous measurements are carried out via a plurality of antenna units 102 on the waveguide antenna array, and the phase difference is calculated. Subsequently, an azimuth angle estimation value

[0044]

Number

[0045] can be determined. The influence of the self - speed v ego of the radar sensor S can be ignored for this type of angle estimation. Therefore, the azimuth angle estimation value

[0046]

Number

[0047] is determined independently of the self - speed v ego of the radar sensor S. In addition to this in angle estimation 6, the elevation angle Φi between the plane in which the vehicle moves and the height at which the target i is captured is determined. Therefore, for each target i, the relative speed

[0048]

Number

[0049] and the azimuth angle estimation value

[0050]

Number

[0051] and, in some cases, the elevation angle Φi are known. Thereby, for each target i, an individual self - speed estimation value

[0052]

Number

[0053] is calculated 7 based on Equation 2

[0054]

Number

[0055] are shown in a distribution diagram for several targets i. Figure 4b shows a histogram in which the determined number n is shown for a large number of different individual self - speed estimates In Figure 4a, for several targets i, the individual self - speed estimates calculated in this way

[0056]

Number

[0057] for each of them. In both figures, it can be recognized that the individual self - speed estimates

[0058]

Number

[0059] cluster in range B. In typical traffic situations, there are clearly more stationary targets than moving targets with the same relative speed in the radial direction to the radar sensor S

[0060]

Number

[0061] are concentrated in range B. In typical traffic situations, there are clearly more stationary targets than moving targets with the same relative speed in the radial direction to the radar sensor S

[0062] Regarding Figure 3, clustering 8 is performed, and in this clustering 8, the individual self - speed estimates within range B

[0063]

Number

[0064] is assigned to the stationary target, and the individual self - speed estimation value outside range B

[0065]

Number

[0066] is assigned to the moving target. Thereby, the moving target is identified (MTI - Moving Target Indication) and separated from the stationary target. Range B is defined through the errors during Measurement 1 and Angle Estimation 6 and is the error tolerance range.

[0067] The individual self - speed estimation value assigned to the stationary target, that is, within range B

[0068]

Number

[0069] is averaged 9 to obtain the combined self - speed estimation value

[0070]

Number

[0071] For example, various types of averaging can be performed, such as classical averaging, such as arithmetic mean, weighted mean depending on the weight of signal - to - noise ratio, determination of the maximum value within the histogram, generation of the median, etc. The combined self - speed estimation value

[0072]

Number

[0073] is calculated in principle without moving targets and is thus an estimate for the actual self - speed ^v of the radar sensor S ego for

[0074]

Number

[0075] can be regarded as. Thus, autofocus is achieved. For each stationary target, in addition, the angle calculation 10 is the relative speed of the stationary target determined by the Keystone process 2 using the Doppler effect

[0076]

Number

[0077] and the calculated individual self - speed estimate value for the stationary target

[0078]

Number

[0079] From these, Equation 3

[0080]

Number

[0081] is used to perform. As a result, a corrected angle estimate value that can be regarded as the actual azimuth angle of the target with respect to the radar sensor S

[0082]

Number

[0083] is calculated. However, since the velocity component of the moving target is unknown and thus cannot be considered, for the moving target, the above - mentioned angle calculation 10 will result in an incorrect angle estimate. Therefore, for the moving target, the azimuth angle estimate value determined during the angle estimation 6

[0084]

Number

[0085] is adopted. As a result, although an improvement in angle estimation is not achieved, incorrect angle estimation is avoided. Finally, the estimated radial velocity of the moving target is the relative velocity determined by the Keystone process 2 using the Doppler shift

[0086]

Number

[0087] from the combined self-velocity estimate determined by averaging 9 for stationary targets

[0088]

Number

[0089] can be calculated by weighting and subtracting with the cosine of the azimuth angle of this target. In FIG. 5, the odometry trajectory T determined using an odometry sensor in the conventional manner O and the trajectory T generated based on an embodiment of the method according to the present invention V are compared. Both trajectories match very well, and thus it can be seen that autofocus using the method according to the present invention has produced accurate results.

Claims

1. Use of a radar sensor (S) comprising a waveguide antenna array having at least two groups (104, 105) of antenna units (102) each comprising a plurality of antenna elements (101), wherein the antenna elements (101) within each antenna unit (102) are arranged side by side in a first direction (R1), in the first group (104) the antenna units (102) are arranged offset from one another in a second direction (R2) perpendicular to the first direction (R1), and in the second group (105) the antenna units (102) are arranged offset from one another in the first direction (R1), for determining an estimated value of its own velocity 【Number 1】 and an estimated value of the angle of a target (i) 【Number 2】 by means of the following steps, namely - measuring (1) by means of the radar sensor (S) the distance (A) between the radar sensor (S) and each respective target (i); - measuring (1) by means of the radar sensor (S) the relative velocity 【Number 3】 of each respective target (i) using the Doppler effect; - angle-estimating (6) an estimated value of the anglecharacterizing the direction of the radar sensor's own velocity and each respective target (i); 【Number 4】 - for each target (i), determining (7) an individual estimated value of the radar sensor's own velocity using the relative velocityand the estimated value of the angle; [Number 5] - classifying and sorting (8) the individual estimated values of the own velocityinto stationary targets for which the individual estimated values of the own velocityare all within a configurable range (B), and moving targets for which the individual estimated values of the own velocityare outside said range (B); 【Number 6】 - determining (9) a combined estimated value of the own velocityfrom the individual estimated values of the own velocityof the stationary targets; 【Number 7】 - determining (10) a corrected estimated value of the anglefor the stationary targets using the combined estimated value of the own velocityand the measured relative velocityfor each of them. Use of a radar sensor for a method having these steps.

2. 【Number 8】 Use of a radar sensor for a method according to claim 1, wherein in the second group the antenna units are additionally arranged offset from one another in the second direction. 【Number 9】

3. 【Number 10】 Use of a radar sensor for a method according to claim 1 or 2, wherein the array groups are alternately assigned to the transmitting or receiving side.

4. 【Number 11】 Use of a radar sensor for a method according to claim 1 or 2, wherein the configurable range (B) is based on the relative velocity 【Number 12】 ​ ​ 【Number 13】 ​ 【Number 14】 ​ 【Number 15】 ​ ​ ​ ​ ​ ​ ​ 【Number 16】 Use of a radar sensor for a method according to any one of claims 1 to 3, which is an error tolerance range determined from the error regarding the measurement (1) and the error regarding the angle estimation (6).

5. Use of a radar sensor for a method according to any one of claims 1 to 4, wherein the averaged speed value regarding the stationary target is determined as a combined own speed estimation value by weighted average or non-weighted average. 【Number 17】

6. Use of a radar sensor for a method according to any one of claims 1 to 5, wherein, regarding a moving target, the angle estimation value resulting from the angle estimation (6) is adopted (11) as the angle estimation value for the moving target.

7. 【Number 18】 Use of a radar sensor for a method according to any one of claims 1 to 6, wherein the speed estimation value for a moving target is determined (12) from the relative speed of the target measured using the Doppler effect.

8. Use of a radar sensor for a method according to any one of claims 1 to 9, wherein the individual own speed estimation values of the radar sensor (S) having a synthetic aperture are used for the relative speed and the angle estimation value regarding each target (i). 【Number 19】

9. Use of a radar sensor for a method according to any one of claims 1 to 8, wherein the radar sensor (S) is a chirp sequence radar.

10. 【Number 20】 Use of a radar sensor for a method according to any one of claims 1 to 9, wherein the determination of the relative speed using the Doppler effect is performed by Keystone processing (2). 【Number 21】 ​ 【Number 22】 When determining (7) using, the elevation angle (Φ ｉ ) is taken into account, use of a radar sensor for the method according to any one of claims 1 to 7. ​ ​ ​ ​ 【Number 23】 ​

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