Use of radar sensor with waveguide antenna array in method for determining speed estimate and angle estimate of target itself

Abstract

The invention relates to the use of a radar sensor having a waveguide antenna array with at least two groups of antenna units having a plurality of antenna elements, the antenna elements being arranged next to one another in a first direction in each antenna unit, the antenna elements are arranged in a first group (104) offset from each other in a second direction, the second direction being perpendicular to the first direction, and wherein the antenna elements are arranged in a second group offset from each other in the first direction, having the following steps for a method for determining an own velocity estimate and an angle estimate of the target. The respective distance between the radar sensor having the synthetic aperture and the respective target is measured by means of the radar sensor having the synthetic aperture. Furthermore, the respective relative speed of the respective target is measured by means of the Doppler effect by means of a radar sensor having a synthetic aperture. Angle estimates are made of angle estimates characterizing the angle between the direction of the own velocity of the radar sensor having the synthetic aperture and the respective target. An individual own velocity estimate (formula A) of a radar sensor having a synthetic aperture is then ascertained using the relative velocity and angle estimates for each target. According to the invention, individual velocity estimates associated with the following static targets and individual velocity estimates associated with the following moving targets (formula A) are classified and divided, the individual velocity estimates of the static targets lying within a predefined region (B) in relation to each other, and the individual velocity estimates of the moving targets lying within the predefined region (B). The individual velocity estimate (formula A) of the moving object is outside the region (B). For a static target, a combined self-speed estimated value is obtained from an individual self-speed estimated value (formula A) of the static target. Finally, a corrected angle estimate is determined for the static target by means of the combined own speed estimate and the correspondingly measured relative speed.

Description

Technical Field

[0001] The present invention belongs to the field of radar sensing and particularly relates to the fields of Multiple-Input-Multiple-Output (MIMO) and Synthetic Aperture Radar (SAR) radar. Background Art

[0002] Radar systems for measuring the distance, relative speed and angle of objects are increasingly used in motor vehicles for safety and comfort functions. Today, radars with multiple input multiple output (MIMO) are used for this purpose, i.e. radars with many transmission channels for transmitting and receiving radar signals. Recently, synthetic aperture (SAR) radars have become known. The principle of synthetic aperture allows more accurate angle measurement, especially when the radar sensor itself moves. Synthetic aperture uses the situation that the transmitting antenna and the receiving antenna are present at different geographical locations at each measurement time point due to the radar sensor's own movement. The measurement is then processed into a synthetic antenna aperture. In the analysis and evaluation, this can be equated with a large antenna aperture along the driving trajectory. Therefore, a large synthetic aperture is achieved, which may be impractical or completely impossible with an actual antenna aperture due to the large number of necessary antenna elements. In angle measurement, a higher resolution is possible through synthetic aperture (SAR) compared to the actual antenna aperture.

[0003] In order to evaluate the measured radar signal as a synthetic aperture, it is usually assumed that the radar surroundings are static. In addition, the radar sensor's own motion and therefore the following positions should be known, at which individual measurements are performed. The radar's trajectory is input into the SAR analysis and evaluation algorithm and the trajectory description is the basis for the SAR image calculation. It may be sufficient to calculate the own velocity estimate for the SAR image instead of a more accurate trajectory according to the analysis and evaluation algorithm. Therefore, it is typically assumed that the trajectory is linear, and complex trajectories are otherwise not imageable.

[0004] Nowadays, radar systems in the motor vehicle sector usually use frequency modulated continuous wave radars (FMCW: frequency moduliertes Dauerstrichradar), which have a rapidly increasing ramp - the so-called fast chirp modulation (Fast-Chirp-Modulation) - in which multiple linear frequency ramps can be run in succession with the same steep slope. The current mixing of the transmit signal and the receive signal produces a low-frequency signal (the so-called clock frequency), the frequency of which is proportional to the distance. The system is usually designed in such a way that the share of the clock frequency caused by the Doppler frequency is negligible. The distance information obtained is largely clear. In addition, by observing the time development of the phase of the complex distance signal on the ramp, the Doppler shift can be determined and the relative speed can be determined from this. The distance and the relative speed are determined independently of each other. For this purpose, a two-dimensional Fourier transform is usually used.

[0005] Conventional SAR analysis is based on static targets. The assumed moving targets do not hold true, leading to erroneous, offset angles and blurred imaging in the SAR images. However, in the case of motor vehicles, moving targets are also of interest (e.g., to avoid collisions with such motor vehicles). In order to estimate the own trajectory or own speed of the radar sensor, two methods are known: one is to use external sensors, such as inertial measurement units (IMUs) or odometer sensors. The other is to use very computationally intensive autofocus algorithms that are not available for real-time processing. Summary of the invention

[0006] The subject of the invention is a method for determining own velocity estimates and angle estimates of multiple targets in an environment using a radar sensor with a waveguide antenna array as described in detail below, the method steps of which are described in detail below.

[0007] The waveguide antenna array of the radar sensor has at least two groups of antenna units, wherein in each antenna unit the antenna elements are arranged next to each other in a first direction. In the first group, the antenna units are arranged offset from each other in a second direction perpendicular to the first direction. In the second group, the antenna units are arranged offset from each other in the first direction. Thus, a radar sensor with multiple input and multiple output (MIMO) is created.

[0008] The radar sensor uses digital beam forming (DBF) so that the antenna elements of the antenna units can receive and evaluate radar signals. The first group with antenna units in the second direction is preferably used to measure the azimuth angle and the second group with antenna units in the first direction is preferably used to measure the elevation angle.

[0009] In the second group, it can be provided that the antenna elements are arranged offset relative to one another only in the first direction. This leads to a reduction in the computational overhead during digital beamforming. Optionally, in the second group, the antenna elements can also be arranged offset relative to one another in the second direction. Thus, for the second group, measurements in the second direction can be realized and the radar sensor is designed as a multiple-input multiple-output (MIMO).

[0010] Preferably, the array groups are alternately assigned either to the transmitting side or to the receiving side. According to the MIMO principle, the transmitting and receiving antennas are in principle interchangeable.

[0011] In the following, a distinction is made between static objects (also called stationary objects) and moving objects (also called moving objects). Static objects are objects in the surroundings that do not move themselves, i.e., for example, buildings, trees, infrastructure on or near the street, etc. Moving objects are moving objects in the surroundings, i.e., for example, other motor vehicles, pedestrians, other traffic participants, etc.

[0012] The radar sensor itself moves and therefore transmits a plurality of measurement signals and receives signals reflected by the target. The radar sensor is therefore a radar sensor with a synthetic aperture. For each target, the relative speed is determined from the transmitted and received signals. In order to determine the relative speed, the Doppler effect is evaluated in the measurement signal and in particular the Doppler shift is determined. In addition, the distance between the radar sensor and the target is also determined from the transmitted and received signals. This can be done, for example, via Fourier processing. In order to distinguish the target in the measurement, detection with a constant false alarm rate (CFAR: constant false alarm rate) is performed.

[0013] A rough angle estimation is then performed. An angle estimate is therefore estimated for each target, which represents the target angle between the direction of the radar sensor's own velocity, i.e. the direction of the radar sensor's own movement ("forward direction"), and the respective target. The angle estimation can be performed, for example, with the aid of digital beamforming. For this purpose, the radar sensor has at least one additional receiving channel and / or at least one additional transmitting channel. Preferably, the angle estimate directly gives the target angle. Although the target angle can also be indirectly known from a transformation or from a mathematical relationship of the angle estimate. Since the angle estimate is still processed later, the angle estimate may be significantly less accurate than a conventional angle measurement.

[0014] The individual own speed estimates of the radar sensor are calculated for each target individually by backprojection with the aid of the relative speed and angle estimates. This means that measured or estimated values ​​are used for each target in order to obtain the individual own speed estimates of the radar sensor therefrom respectively. Therefore, a large number of individual own speed estimates are typically determined, which are therefore dependent on the target speed. For static targets, the individual own speed estimates are closer together, because the relative speed between the target and the radar sensor is proportional to the own speed of the radar sensor and the angle with the target. For moving targets, the individual own speed estimates are farther apart, because the relative speed depends not only on the relative speed of the radar sensor itself and the angle with the target, but also on the speed of the target. In addition, in typical cases, there are significantly more static targets in the surrounding environment than moving targets with the same relative speed as the radar sensor, and moving targets normally have different speeds from each other.

[0015] Therefore, it is possible to classify and divide the individual own speed estimation values, especially by clustering. For this purpose, a region is defined for the individual own speed estimation values, through which a distinction can be made between static targets and moving targets. The individual own speed estimation values ​​that are within a predetermined region relative to each other are assigned to static targets. The individual own speed estimation values ​​that are outside the region are assigned to moving targets. Thus, moving targets can be identified (moving target indication MTI-Moving Target Indication). The separately calculated individual own speed estimation values ​​can be recorded, for example, in a histogram for classification.

[0016] The individual own speed estimates are then evaluated separately depending on the assignment. For static objects, a combined own speed estimate is determined from the individual own speed estimates assigned to the static object. The combined own speed estimate is regarded as the true speed of the radar sensor, since it is essentially calculated only from static objects (autofocus). In addition, for static objects, a corrected angle estimate is calculated using the combined own speed estimate and the corresponding measured relative speed. The corrected angle estimate can be regarded as the true angle of the object relative to the radar sensor.

[0017] Furthermore, the method enables the determination of the own speed estimate and angle estimate directly from the measurements without the need for additional sensors, such as an IMU or an odometer sensor. Typical odometer sensors used in motor vehicles are usually arranged remotely from the radar sensor and also perform too few measurements per time interval.

[0018] The described method combines a waveguide antenna with a MIMO and SAR concept by using a radar sensor with a waveguide antenna array. Thus, the same antenna unit or antenna element is used both for MIMO and for SAR. As a result, the number of radar sensor channels can be reduced and the antenna area can be minimized. In particular, reducing the number of channels is a huge advantage in waveguide antennas, because they typically require a lot of space due to their three-dimensional structure and require a high production cost.

[0019] The use of waveguide antennas allows for a large degree of freedom in the arrangement of the antenna array elements. Thus, an advantageous λ / 2 arrangement of the antenna elements can be realized in a simpler manner, which arrangement is advantageous both with regard to the dynamics and with regard to a unique and unambiguous angle estimation.

[0020] Therefore, the radar signal received, down-mixed and sampled at baseband by the antenna array must be compatible with the combination of MIMO and SAR to achieve a unique and unambiguous sampling of the Doppler frequency. rel,r,u The clearly detectable area of ​​the radial section applies:

[0021]

[0022] Here, v rel,r,max and v rel,r,min are the upper and lower limits of this region. represents the bandwidth of the largest uniquely detectable Doppler frequency, c represents the wave propagation speed, J c represents the transmission frequency of the radar signal, Indicates the duration between two frequency slopes (chirp-to-chirp) of the same transmit antenna.

[0023] In the time division multiplexing method, two frequency slopes The duration between the two increases with the number of transmitters at a fixed bandwidth and a fixed ramp steepness or ramp duration, so that the number of transmitters based on time multiplexing is limited in conventional FMCW-MIMO radar sensors. Preferably, in the present invention, multiplexing is performed in the frequency dimension (Frequency Division Multiplexing FDM) or in the code dimension (Code Division Multiplexing CDM). For SAR, there is no such restriction on the number of transmitters.

[0024] Advantageously, the predefined area used in the classification and classification of the individual intrinsic speed estimates is the error tolerance range of the measurement. This range is determined from the error of the relative speed measurement and the error of the angle estimation. This allows for a special classification for the measurement within the error limits and thus provides the greatest possible selectivity.

[0025] In order to determine the combined own speed estimate, an average speed value of the individual own speed estimates can be calculated. For this purpose, classical averaging can be performed, such as arithmetic mean, weighted averaging (with weighting depending on the signal-to-noise ratio, for example), determining the maximum value in a histogram, finding the median, etc.

[0026] Preferably, the corresponding angle estimate and the corresponding speed estimate are also obtained for the moving target. Because the speed of the moving target is not known, the analysis and evaluation described above may lead to erroneous angle estimates. The angle estimate obtained for the same moving target in the above-mentioned angle estimation can be used as the angle estimate of the corresponding moving target. Therefore, although an improved angle estimation is not achieved, an erroneous angle estimation is avoided. In addition, the radial velocity estimate of the corresponding moving target can be obtained from the relative velocity measured by means of the Doppler deviation. For this purpose, the combined own velocity estimate obtained above is assumed as the radar's own velocity and is weighted with the cosine of the target angle, and it is subtracted from the relative velocity.

[0027] The movement of both the radar and the moving objects is assumed to be two-dimensional in a plane. However, the objects measured by the sensor can be located at different heights relative to the plane. This can occur in particular when, for example, only parts of the object are detected. In this case, the elevation angle between the plane and the object can be determined for the object. Preferably, the elevation angle is taken into account for each object when determining the individual own velocity estimate of the radar sensor using the relative speed and the estimated angle.

[0028] The radar sensor is preferably a chirp sequence radar, which operates as a frequency modulated continuous wave radar and emits a chirp signal with a rapidly rising ramp. The distance can thus be easily measured in a manner known per se. Furthermore, the Doppler effect, in particular the Doppler shift, can be determined from the temporal development of the phase of the complex distance signal on the ramp and thus the relative speed can be measured.

[0029] For determining the relative speed by means of the Doppler effect, methods known per se can be used. In this case, a Keystone process based on the Chirp-Z transform (CZT) is preferred, since it is particularly computationally efficient and can compensate for any shift effects that occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary embodiments of the invention are depicted in the drawing and are explained in more detail in the following description.

[0031] The accompanying drawings show:

[0032] Figure 1 : shows an isometric view of a waveguide antenna of a radar sensor, which is used in the method according to the present invention.

[0033] Figure 2 : Schematic diagram showing a traffic situation, a motor vehicle with a radar sensor and different objects with associated angles and relative speeds.

[0034] Figure 3 : A flow chart showing an embodiment of the method.

[0035] Figure 4a : A distribution diagram showing the individual own velocity estimates of the radar sensors for different targets.

[0036] Figure 4b : Shows from Figure 4a Histogram of the distribution of .

[0037] Figure 5 : shows a position diagram of a trajectory, which is generated according to an embodiment of the method according to the invention and the trajectory is generated with the aid of an odometer sensor. DETAILED DESCRIPTION

[0038] Figure 1 1 shows a waveguide antenna 100 of a radar sensor S (not shown in detail here). The waveguide antenna 100 has a waveguide antenna array consisting of a plurality of antenna elements 101. The plurality of antenna elements 101, 12 in each case, are arranged in a row in a first direction R1 and together form an antenna unit 102 (in Figure 1 The antenna units are exemplarily marked with boxes. In this example, in the global reference system, the first direction R1 corresponds to a vertical line. The antenna elements 101 of the antenna unit 102 jointly transmit and receive radar signals. Figure 1 A phase center 103 is identified for each antenna element 102. The antenna elements 102 of the waveguide antenna array are divided into two groups 104, 105. In this example, the first group 104 includes eight antenna elements 102, each of which has 12 antenna elements 101 arranged in a row in a first direction R1. In the first group 104, the antenna elements 102 are arranged offset from one another in a second direction R2. In this example, in the global reference system, the second direction R2 corresponds to one of the horizontal lines and in this example at the own speed v of the motor vehicle F. ego Extending in the direction of Figure 2 The motor vehicle F has a radar sensor S. The second direction R2 is usually related to the own speed v of the motor vehicle F.ego It can also be at a certain angle. Therefore, only the antenna pole is swung. The second direction R2 is connected to the azimuth angles α1, α2, α3 and the first group 104 of antenna units 102 is used to measure the azimuth angles α1, α2, α3. In this example, the second group 105 includes three antenna units 102, which 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 offset from each other not only in the first direction R1 but also in the second direction R2. The second group 105 of antenna units 102 is used to measure the elevation angle φ i And for measuring azimuth angles α1, α2, α3. In the state shown here, the first group 104 of antenna units 102 is assigned to the receiving side RX and the second group 105 of antenna units 102 is assigned to the transmitting side TX. The radar signals received by the first group 104 are processed by digital beam forming. However, the allocation can also be swapped so that 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 embodiments not shown, the antenna units 102 in the second group 105 are arranged offset from each other only in the first direction R1. Therefore, the two-dimensional digital beam forming is simplified. For the method described below, a radar sensor S with the described waveguide antenna 100 or the described waveguide antenna array is used.

[0039] Figure 2 A schematic diagram of a traffic situation is shown with a motor vehicle F having a radar sensor S 100 with a waveguide antenna as described above and a plurality of other motor vehicles, which are marked as objects Z1 to Z3. Typically, there are other objects in the surroundings that are not described here, such as buildings, street infrastructure, traffic signs, guardrails and the like, or the street itself. The motor vehicle F and therefore the radar sensor S are moving at their own speed v ego Moving in a straight line. The radar sensor S shows the velocity v of each target Z1, Z2, Z3 described. ego and the azimuth angles α1, α2, α3 between the respective targets Z1, Z2, Z3. In addition, the relative speed v of each target Z1, Z2, Z3 relative to the radar sensor S is shown. rel,1 、v rel,2 、v rel,3 If a target, such as target Z1, is a static target, that is, the target itself does not move, then the associated relative velocity v rel,1 As the radar sensor S's own speed v ego The projection of i Given above. Figure 1The projections for all three targets Z1, Z2, and Z3 are shown in FIG. Among moving targets, for example, target Z2 moving at an unknown speed, the speed of target Z2 is the relative speed v rel,2 part of and the measured relative velocity v rel,2 Deviation from the projection.

[0040] Figure 3 A flow chart of an embodiment of the method according to the invention is shown. For this purpose, several targets, which are usually marked here with i, are studied. Measurement 1 is performed during the movement of the motor vehicle F and the radar sensor S. Measurement 1 is performed with the aid of frequency modulated continuous wave radar modulation (FMCW), in which a chirp signal with a rapidly rising linear frequency ramp of the same slope is given within a predetermined time interval. The reflected signal is received and processed as a received signal. The mixing of the existing transmitted signal and the received signal gives a low-frequency clock signal, the frequency of which is proportional to the distance of the target i. Measurement 1 is performed in such a way that the Doppler effect or Doppler shift in the clock frequency is negligible or is taken into account in the evaluation.

[0041] Keystone processing 2 is performed below. For this purpose, an estimation of the Doppler shift or Doppler frequency is performed by determining the time evolution of the phase of the complex measurement signal on the frequency ramp and compensating the corresponding linear distance change (drift) in this time evolution for each estimated value. The relative speed is thus determined for each target i The distance estimation is then performed with the aid of conventional Fourier processing 3, in particular the fast Fourier transform (FFT) from the time domain to the frequency domain. The resulting two-dimensional spectrum (range and speed) of the individual transmit-receive channel combinations is incoherently averaged. For this purpose, the amplitude of each individual such spectrum is formed and these amplitudes or the squares of the amplitudes are added. In order to distinguish the target in the measurement, detection 5 with a constant false alarm rate (CFAR) is performed.

[0042] In addition, an angle estimation 6 is performed to obtain an estimated azimuth angle for the target. Azimuth estimate represents the azimuth angle between the measuring axis of the radar sensor S and the target i and therefore also reflects the installation conditions of the radar sensor S. Since the installation conditions are known, the azimuth angle estimate It can be converted into its own speed v through coordinate transformation ego The azimuth angle α between the direction of i For the estimated value of Figure 2 In the case shown in Figure 1, the measuring axis is perpendicular to the velocity v ego direction. Therefore, the following relationship exists: θ i =90-α iDigital beam forming is used for the angle estimation 6. Therefore, measurements are performed simultaneously on the waveguide antenna array via multiple antenna units 102 and phase differences are calculated, from which an azimuth angle estimate can be obtained. The radar sensor S's own speed v ego The influence of is negligible for this type of angle estimation, making it independent of the radar sensor S’s own velocity v ego Get the estimated azimuth Furthermore, in the angle estimation 6 the elevation angle φ between the plane in which the motor vehicle is moving and the height at which the object i is detected is ascertained. i .

[0043] So for each target i, the azimuth estimate Relative speed and, if necessary, the elevation angle φ i is known. Therefore, for each target i, 7 individual self-velocity estimates are calculated separately according to formula 2:

[0044]

[0045] exist Figure 4a The individual self-velocity estimates for some targets i calculated in this way are shown in FIG. Figure 4b A histogram is shown in which the estimated values ​​of the individual own speed are plotted for a number of different The number of obtained values ​​n is plotted separately. In both figures, we can see that the individual's own speed estimate The radar sensor S accumulates in area B. In typical traffic situations, there are significantly more static objects having the same relative speed radially relative to the radar sensor S than moving objects.

[0046] refer to Figure 3 Grouping 8 is performed, in which the estimated speed of individuals in area B is Assigned to static targets, and the estimated speed of individuals outside area B Assigned to moving targets. Moving targets are thus identified (MTI—Moving Target Indication) and separated from static targets. In the measurement 1 and in the angle estimation 6, the region B is defined by the error and the error tolerance region is shown.

[0047] Individual own velocity estimates assigned to static targets That is, the estimates within region B are averaged 9 to obtain the combined own speed estimate Different kinds of averaging can be performed, such as classical averaging, such as arithmetic averaging, weighted averaging (e.g. with signal-to-noise ratio-dependent weighting), determining the maximum value in a histogram, finding the median, etc. Since the combined own velocity estimate In principle, it is calculated without a moving target and can be regarded as the true own speed of the radar sensor S. Estimated value of Therefore, autofocus is achieved. In addition, an angle calculation 10 is performed for each static target, using the relative speed obtained by Keystone processing 2 with the help of the Doppler effect. For a static target and from the individual's own velocity estimate calculated for the static target This calculation is performed with the help of Formula 3:

[0048]

[0049] So the corrected angle estimate is calculated This angle estimate can be regarded as the true azimuth of the target relative to the radar sensor S.

[0050] For moving objects, the angle calculation 10 described above may lead to an erroneous angle estimate, since the velocity component of the moving object is unknown and therefore cannot be taken into account. Therefore, for moving objects, the azimuth angle estimate determined in the angle estimation 6 is used. Although an improved angle estimation is not achieved, an erroneous angle estimation is avoided. The radial velocity estimate of the moving object can then be calculated 12 by averaging the combined own velocity estimate determined for the static object 9. The target azimuth is weighted by the cosine of the target azimuth and is taken from the relative velocity determined by Keystone processing 2 with the aid of the Doppler shift. Minus.

[0051] exist Figure 5 The odometer trajectory T is shown in o and trajectory T v The comparison between the two is to obtain T in the traditional way with the help of the odometer sensor o , according to an embodiment of the method of the present invention, T v It is evident that the two trajectories correspond very well and that the autofocusing therefore provides precise results with the method according to the invention.

Claims

1. A radar sensor (S) with a waveguide antenna array is used to determine an estimate of the target (i)'s own velocity. and the angle estimate The invention relates to an application of a method of the invention, wherein the waveguide antenna array has at least two groups (104, 105) of antenna units (102), each of which has a plurality of antenna elements (101), wherein: In each antenna unit (102), antenna elements (101) are arranged side by side in a first direction (R1), wherein in a first group (104), the antenna units (102) are arranged offset with respect to one another in a second direction (R2), the second direction being perpendicular to the first direction (R1), and wherein in a second group (105), the antenna units (102) are arranged offset with respect to one another in the first direction (R1), the method comprising the following steps: - measuring (1) a distance (A) between the radar sensor (S) and the corresponding object (i) by means of the radar sensor (S), - using the radar sensor (S) to measure (1) the relative speed of the corresponding target (i) by means of the Doppler effect -Estimated angles Performing angle estimation (6), wherein the angle estimation value represents the angle between the direction of the own speed of the radar sensor (S) and the corresponding target (i); - by means of the relative speed of each target (i) and the angle estimate Obtain (7) the estimated value of the individual own speed of the radar sensor (S) - Estimates of the individual's own velocity relative to the following static targets and the individual self-speed estimation values ​​related to the following moving targets are classified and divided, the individual self-speed estimation values ​​of the static targets are The individual speed estimates of the moving targets are located within a predetermined area (B). is outside said area (B); - The estimated velocity of the static object Calculate the estimated value of the self-speed of the combination (9) and - For the static target, using the combined own velocity estimate and the relative speeds measured respectively Obtain the corrected angle estimate (10) 2. Use of the radar sensor according to claim 1 in the method, wherein: In the case of the second group, the antenna elements are additionally arranged offset with respect to one another in a second direction.

3. Use of the radar sensor according to claim 1 or 2 in the method, wherein: Array groups are alternately assigned either to the transmit side or to the receive side.

4. Use of a radar sensor according to any one of the preceding claims in the method, wherein: The predetermined area (B) is an error tolerance area, and the error tolerance area is determined by the relative speed The measurement error (1) is obtained from the error of the angle estimation (6).

5. Use of a radar sensor according to any one of the preceding claims in the method, wherein: The average speed of the static target is determined by weighted or unweighted averaging as a combined own speed estimate 6. Use of a radar sensor according to any of the preceding claims in the method, wherein: For a moving target, the angle estimation value obtained by the angle estimation (6) is The angle estimation value for the moving target is adopted.

7. Use of a radar sensor according to any of the preceding claims in the method, wherein: The relative speed of the target measured by means of the Doppler effect Obtain the estimated velocity of the moving target in (12).

8. Use of a radar sensor according to any of the preceding claims in the method, wherein: For each target (i), the relative speed and the angle estimate Obtain (7) the estimated value of the individual own velocity of the radar sensor (S) with synthetic aperture When considering the elevation angle (φ i ).

9. Use of a radar sensor according to any of the preceding claims in the method, wherein: The radar sensor (S) is a chirp sequence radar.

10. Use of a radar sensor according to any of the preceding claims in the method, wherein: The relative speed The determination of is carried out with the aid of the Doppler effect and the Keystone process (2).

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