METHOD AND DEVICE FOR EVALUATING THE ANGULAR POSITION OF AN OBJECT, AND DRIVER ASSISTANCE SYSTEM

Abstract

A method for evaluating an angular position of an object recognized on the basis of radar data, the radar data being ascertained by a radar device. The method includes: ascertaining of an intrinsic speed of the radar device; ascertaining a relative speed of the recognized object in relation to the radar device, using the ascertained radar data; ascertaining at least one angular test region using the ascertained intrinsic speed and the ascertained relative speed, the at least one angular test region corresponding to possible stationary objects that have a relative speed that substantially corresponds to the ascertained relative speed; and ascertaining whether an azimuth angle of the recognized object lies in the ascertained angular test region.

Claims

1-10. (canceled)

11. A method for evaluating an angular position of an object recognized based on radar data, the radar data being ascertained by a radar device, the method comprising the following steps: ascertaining an intrinsic speed of the radar device; ascertaining a relative speed of the recognized object in relation to the radar device, using the ascertained radar data; ascertaining at least one angular test region using the ascertained intrinsic speed and the ascertained relative speed, the at least one angular test region corresponding to a possible stationary object that has a relative speed that corresponds substantially to the ascertained relative speed; and ascertaining whether an azimuth angle of the recognized object lies in the ascertained angular test region.

12. The method as recited in claim 11, wherein the ascertaining of whether the azimuth angle of the recognized object lies in the ascertained angular test region includes calculating an angular quality measure using the radar data, and wherein, it is ascertained that the azimuth angle of the recognized object lies in the ascertained angular test region when the angular quality measure exceeds a specified threshold value.

13. The method as recited in claim 12, wherein when the angular quality measure falls below the specified threshold value: (i) it is ascertained that the azimuth angle of the recognized object does not lie in the ascertained angular test region, and (ii) an ascertaining of the azimuth angle outside the angular test region takes place.

14. The method as recited in claim 11, wherein the at least one angular test region is further determined based on a mounting angle of the radar device.

15. The method as recited in claim 11, wherein the at least one angular test region is ascertained taking into account a degree of accuracy of the ascertained intrinsic speed and the ascertained relative speed.

16. The method as recited in claim 11, wherein at least one central angle is calculated that corresponds to a possible stationary object that has a relative speed that is equal to the ascertained relative speed, a respective angular test region around the at least one central angle being ascertained through variation of the ascertained intrinsic speed and the ascertained relative speed in consideration of accuracy.

17. The method as recited in claim 16, wherein overlapping angular test regions are combined to form an overall angular test region.

18. The method as recited in claim 11, wherein the ascertaining of whether the azimuth angle of the recognized object lies in the ascertained angular test region taking place based on a maximum likelihood method.

19. A device for evaluating an angular position of an object recognized based on radar data, the device comprising: an interface configured to receive the radar data and information ascertained by a radar device relating to an intrinsic speed of the radar device; and a computing device configured to ascertain a relative speed of the recognized object in relation to the radar device using the ascertained radar data, to ascertain at least one angular test region using the ascertained intrinsic speed and the received relative speed, the at least one angular test region corresponding to a possible stationary object that has a relative speed that corresponds substantially to the ascertained relative speed, and to ascertain whether an azimuth angle of the recognized object lies in the ascertained angular test region.

20. A driver assistance system for a vehicle, comprising: a radar device configured to ascertain radar data and to recognize an object based on the radar data; and a device for evaluating an angular position of the object recognized based on the radar data, the device including: an interface configured to receive the radar data and information ascertained by the radar device relating to an intrinsic speed of the radar device; and a computing device configured to ascertain a relative speed of the recognized object in relation to the radar device using the ascertained radar data, to ascertain at least one angular test region using the ascertained intrinsic speed and the received relative speed, the at least one angular test region corresponding to a possible stationary object that has a relative speed that corresponds substantially to the ascertained relative speed, and to ascertain whether an azimuth angle of the recognized object lies in the ascertained angular test region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a schematic diagram of a device for evaluating an angular position according to a specific embodiment of the present invention.

[0026] FIG. 2 shows a first possible relative positioning of the radar device and a possible object as a function of a measured relative speed.

[0027] FIG. 3 shows a second possible relative positioning of the radar device and a possible object as a function of a measured relative speed.

[0028] FIG. 4 shows an illustration of corresponding angular test regions.

[0029] FIG. 5 shows a schematic diagram of a driver assistance system according to a specific embodiment of the present invention.

[0030] FIG. 6 shows a flow diagram of a method for evaluating an angular position of an object according to a specific embodiment of the present invention.

[0031] In all the Figures, identical or functionally identical elements and devices are provided with the same reference characters.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0032] FIG. 1 shows a schematic diagram of a device 1 for evaluating an angular position of an object that was recognized on the basis of radar data. Device 1 includes an interface 2 that is coupled to a radar device 5 and receives radar data from this radar device. Radar device 5 is preferably designed as an MIMO radar device. In particular, the radar device can transmit various frequency ramps using a time-division multiplexing method, for example according to the method describe in U.S. Patent Application Publication No. US 2017/0131392 A1. Through suitable choice of the modulation method, an unambiguous determination of the distance and of the relative speed of the object can be carried out without requiring tracking over several cycles.

[0033] Interface 2 is also coupled to a sensor device 8 of the vehicle that is designed to measure an intrinsic speed of the vehicle. The measured intrinsic speed is transmitted to device 1 via interface 2.

[0034] Device 1 further has a computing device 3 that further evaluates the data received via interface 2. An object can be recognized either by radar device 5 or by computing device 3 on the basis of the radar data. In particular, peaks in a frequency spectrum are evaluated for this purpose. On the basis of the radar data, computing device 3 ascertains a relative speed of the recognized object in relation to the vehicle, or to radar device 5. The calculation of the relative speed can take place on the basis of conventional methods, taking into account the Doppler effect.

[0035] Computing device 3 further has knowledge of a mounting angle of radar device 5, which can for example be stored as a specified value in a memory of device 1.

[0036] Computing device 3 is designed to check whether the recognized object is a stationary target.

[0037] Given fixedly specified values of the mounting angle, the intrinsic speed of the vehicle, and the relative speed of the object, there result two possible angular constellations for the relative position between the vehicle and the object.

[0038] A first possible position is illustrated in FIG. 2. Radar device 5 is installed in a vehicle 6, and a main direction of radiation Y of radar device 5 encloses mounting angle _mount with vehicle axis, or longitudinal axis X of vehicle 6. Vehicle 6 moves along vehicle axis X with intrinsic speed v_ego. Because object 7 is a stationary target, in the coordinate system of vehicle 6 it moves with negative intrinsic speed v_ego. A projection onto a first connecting line Z_a between radar device 5 and object 7 corresponds to relative speed v_rel. Main direction of radiation Y encloses a first azimuth angle _a with first connecting line Z_a, object 7 being situated on a side of main direction of radiation Y facing away from axis X. A first object angle _a of object 7 between first connecting line Z_a and vehicle axis X is thus given as the sum of mounting angle _mount and first azimuth angle _a. Considered geometrically, first azimuth angle _a can be calculated according to the following equation:

[00002]${}_a={\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}}{v_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}$

[0039] A second possible situation is illustrated in FIG. 3. In this case, a second connecting line Z_b that connects object 7 to radar device 5 lies between main direction of radiation Y and vehicle axis X. A second azimuth angle _b between main direction of radiation Y and second connecting line Z_b is given as the difference between mounting angle _mount and a second object angle _b, i.e. by the following equation:

[00003]${}_b=-\left({\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}}{v_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}\right)$

[0040] According to a specific embodiment, computing device 3 first checks whether an actual azimuth angle of object 7, acquired on the basis of the radar data, corresponds to first azimuth angle _a or to second azimuth angle _b.

[0041] In general, relative speed v_rel and intrinsic speed v_ego of vehicle 6 are subject to error. According to further specific embodiments, computing device 3 therefore checks whether the actual azimuth angle of object 7 acquired on the basis of the radar data lies in a first angular region or in a second angular region .

[0042] In FIG. 4, the two angular regions are illustrated. First angular region extends between a first axis Z_a1 and a second axis Z_a2 around first connecting line Z_a. The corresponding azimuth angles relative to main direction of radiation Y lie between a first value

[00004]${\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}+{}_{\mathrm{rel}}}{v_{\mathrm{ego}}-{}_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}$

[0043] and a second value

[00005]${\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}+{}_{\mathrm{rel}}}{v_{\mathrm{ego}}-{}_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}$

[0044] Here, _rel designates the uncertainty of the relative speed v_rel, while _ego designates the uncertainty of intrinsic speed v_ego of vehicle 6.

[0045] Correspondingly, second angular region extends between a third axis Z_b1 and a fourth axis Z_b2 around second connecting line Z_b. The corresponding azimuth angles relative to main direction of radiation Y lie between a first value

[00006]$-\left({\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}+{}_{\mathrm{rel}}}{v_{\mathrm{ego}}-{}_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}\right)$

[0046] and a second value

[00007]$-\left({\cos }^{-1}\left(\frac{-v_{\mathrm{rel}}+{}_{\mathrm{rel}}}{v_{\mathrm{ego}}-{}_{\mathrm{ego}}}\right)-{}_{\mathrm{mount}}\right)$

[0047] For certain constellations, the two angular regions , overlap. In this case, the two angular regions , are combined to form an overall angular region.

[0048] In each case, computing device 3 ascertains an angular quality measure, i.e., a variable that indicates whether object 7 is actually in the respective angular region , . If the angular quality measure exceeds a specified value, then computing device 3 determines that object 7 is a stationary target.

[0049] Otherwise, computing device 3 recognizes that a stationary target is not present, and carries out an angular estimation outside the two angular regions , .

[0050] Thus, on the one hand an evaluation of the angular position can be understood as meaning that it is checked whether what is concerned is an angular position of a stationary object. On the other hand, the precise azimuth angle can also be calculated.

[0051] FIG. 5 illustrates a schematic diagram of a driver assistance system 4 according to a specific embodiment of the present invention. Driver assistance system 4 has a radar device 5 that is installed in vehicle 6. Radar device 5 transmits radar data, and recognizes an object 7 on the basis of the radar data. Driver assistance system 4 further has a device 1 that evaluates the angular position on the basis of the radar data.

[0052] FIG. 6 illustrates a flow diagram of an example method in accordance with the present invention for evaluating an angular position of an object 7.

[0053] In a method step S1, an intrinsic speed v_ego of radar device 5 is ascertained. In particular, radar device 5 can be integrated into a vehicle 6, and intrinsic speed v_ego of vehicle 6 can be calculated by a speed sensor of vehicle 6.

[0054] In a method step S2, a relative speed v_rel of recognized object 7 in relation to radar device 5 is determined using the ascertained radar data.

[0055] In a further step S3, at least one angular test region , is determined as a function of intrinsic speed v_ego, relative speed v_rel, and, if applicable, a mounting angle _mount of radar device 5. Angular test region , corresponds to possible stationary objects 7, and inaccuracies of intrinsic speed v_ego and relative speed v_rel can be taken into account in accordance with the procedures described above.

[0056] In a method step S4, it is checked whether an azimuth angle of recognized object 7 lies in the ascertained angular test region , .