Method and device for detecting and evaluating objects in the vicinity of a motor vehicle

• US 20030036850A1
• Filed: 12/07/2001
• Published: 02/20/2003
• Est. Priority Date: 12/24/1999
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Brosche, Thomas
• Granted Patent: US 6,611,759 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: G01S 13/53 performing filtering on a single spectral line and associated with one or more range gates with a phase detector or a frequency mixer to extract the Doppler information, e.g. pulse Doppler radar G01S13/5244 takes precedence
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles

Abstract

A method and a device are proposed for acquiring and evaluating objects in the surrounding area of a vehicle, in which, using at least one radar sensor (2), the target objects (5, 6; 10) in a monitoring area (1) are acquired, and in at least one evaluation unit the distance data and/or velocity data of the target objects (5, 6; 10) are evaluated. The acquisition of the target objects takes place within a virtual barrier (4; 4.1, 4.2) that can be modified in its distance from the vehicle (3) and in its length (Δx_VB), and, using a transmission signal of a pulse radar sensor (2), the receive signal reflected from the target object (5, 6; 10) can be evaluated in one or more receive channels (20, 21) in such a way that different locus resolutions and different dimensions with respect to distance and length (Δx_VB) of the virtual barrier (4; 4.1, 4.2) can be achieved.

Claims

1. A method for acquiring (detecting) and evaluating objects in the area surrounding a vehicle (3), in which

using at least one radar sensor (2), the target objects (5, 6;

10) in a monitoring area (1) are acquired, and the distance data and/or velocity data of the target objects (5, 6;

10) are evaluated in at least one evaluation unit,

wherein

the acquisition of the velocity of the target objects takes place within a virtual barrier (4;

4.1, 4.2) that can be modified in its distance (x₀) from the vehicle (3) and in its length (Δ

x_VB).

2. The method according to claim 1,

wherein, using a transmission signal of a pulse radar sensor (2), the receive signal reflected from the target object (5, 6;

10) is evaluated in one or more receive channels (20, 21) in such a way that different locus resolutions and different dimensions with respect to distance (x₀) and length (Δ

x_VB) of the virtual barrier (4;

4.1, 4.2) are achieved.

3. The method according to claim 2,

wherein

in a first receive channel (20), the receive signal is processed, using a reference signal having a fixedly set pulse duration (τ

_s) corresponding to the transmission signal, for the acquisition of the distance of the target objects (5, 6;

10), or for setting the distance (x₀) of the virtual barrier (4;

4.1, 4.2),

and wherein

in a second receive channel (21), the receive signal is processed, using a reference signal having a variable pulse duration (τ

_R), for the adjustment of the length (Δ

x_VB) of the virtual barrier (4;

4.1, 4.2), or for the acquisition of the target objects (5, 6;

10) with modifiable locus resolution, or in another distance range.

4. The method according to one of the preceding claims, wherein the following method steps are executed:

a) in the monitoring area (1), an acquisition is carried out of the distance and of the relative velocity (v′

_rel), and, if necessary, of the acceleration (a′

_rel) of the vehicle (3) relative to the respective target object (5, 6;

10),

b) a time interval (t₀) is predetermined for measurement value processing, data transmission, and controlling of the relevant application,

c) the required distance (x_min) of the virtual barrier (4;

4.1, 4.2) from the radar sensor (2), and the length of the measurement area (x_mess) are determined, the distance (X₀) of the virtual barrier (4;

4.1, 4.2) from the radar sensor (2) being selected such that this distance does not fall below the minimum value (x_min),

d) if the instantaneous target distance of the target object (5, 6;

10) is smaller than the sum (x_min+Δ

x_mess), there takes place here an acquisition of velocity and of acceleration (v_rel, v′

_rel, a_rel, a′

_rel) through a measurement of the Doppler frequency (f_d) inside the virtual barrier (4;

4.1, 4.2) with a measurement time (t_mess).

5. The method according to claim 4,

wherein the time interval (t₀) is defined as a function of the relative velocity (v′

_rel) and/or of the acceleration (a′

_rel).

6. The method according to claim 4 or 5,

wherein steps c) and d) are multiply repeated, each with newly calculated values for the length of the virtual barrier (Δ

x_VB) and for the minimum distance (x_min), for the acquisition of a plurality of distance ranges and velocity ranges.

7. The method according to claim 4, 5 or 6,

wherein, in the case in which the previous calculations yield the result that the second measurement of the velocity (v_rel) of a target object (5) is smaller than the first measurement of the velocity (v′

_rel) of the same target object, steps c) and

d) according to claim 4 are repeated with lower values for the distance range (Δ

x_VB≈

Δ

x_mess) and for the minimum distance (x_min).

8. The method according to claim 4, 5, 6, or 7,

wherein from the relative accelerations (a_rel, a′

_rel) between the target objects (5, 6;

10) and the vehicle (3), the velocity (v_c) for the time of a collision is calculated according to the equation;

v_c=v_rel+a_rel*t_mess

or

v_c=v_rel+a′

_rel*t_mess.

9. The method according to one of the preceding claims, wherein the following method steps are executed:

the measurement of the distance of the target objects (5, 6;

10) present in the monitoring area is carried out in one or more receive channels,

the target objects (5, 6;

10) are selected that are relevant for an application,

the relative velocity of the selected target objects (5, 6;

10) is carried out through evaluation of the Doppler frequency within the respective virtual barrier (4;

4.1, 4.2) in one or more receive channels, simultaneous with additional distance measurements in the receive channels used therefor.

10. A device for executing the method according to one of the preceding claims,

wherein a pulse radar sensor (2) has a first receive channel (20), preferably for distance measurement, and has additional receive channels (21), preferably for adjusting the virtual barrier (4;

4.1, 4.2), or likewise for distance measurement, as well as a pulse generator (23) for the production of modulated carrier pulses for the signal of a radar transmitter (24) and demodulation in the receive channels (20, 21).

11. The device according to claim 10,

wherein

for the first receive channel (20), a first pulse duration adjustment unit (25) is present for the pulse duration (τ

_s) with which the signal of the radar transmitter (24) is also charged and is routed to a pulse input (27) of the first receive channel (20) via a delay unit (26) as a reference signal, preferably for the distance measurement, and

for the second receive channel (21), an adjustment unit (28) for the pulse duration (τ

_R) is present that can be modified continuously or discretely, and a delay unit (29) is present, this pulse signal being routed, preferably as a reference signal, to a pulse input (30) of the second receive channel (21) for the adjustment of the length and of the distance of the virtual barrier (4;

4.1, 4.2), or for the distance measurement with a modifiable locus resolution.

12. The device according to claim 10 or 11,

wherein the mixer for the mixing of the transmission signal and of the signal supplied by the reception antenna (22) in the respective receive channel (20, 21) is an I/Q mixer.

13. The device for executing the method according to one of claims 1 to 9,

wherein the radar sensor (2) contains an FMCW radar system that is equipped with one or more receive channels.

14. A method or a device according to one of the preceding claims,

wherein the evaluation of the received radar signal is executed in one or more receive channels through a combination of chronologically sequential and/or chronologically parallel evaluation in the receive channels.