Environment Monitoring System for a Vehicle

• US 20130162461A1
• Filed: 07/30/2011
• Published: 06/27/2013
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: ZF CV Systems Europe BV
• Original Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Inventors: Lucking, Christoph, Risse, Rainer, Ronnenberg, Udo, Stender, Axel
• Granted Patent: US 9,459,347 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 15/878 wherein transceivers are operated, either sequentially or simultaneously, both in bi-static and in mono-static mode, e.g. cross-echo mode
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2015/938 in the bumper area radar in bumper area G01S2013/93275; bumper with obstacle sensor of electric or electronic type B60R19/483

Abstract

The invention relates to an environment monitoring system (3) for a vehicle (1), wherein the environment monitoring system (3) comprises: at least two distance sensors (4-1, 4-2, 4-3) for detecting distance by measuring the propagation time of detection signals, wherein the distance sensors (4-1, 4-2, 4-3) are each designed as a transmitting unit and receiving unit for the detection signal and, in a direct operating mode, emit detection signals, receive reflected components of the detection signals emitted by the distance sensors; and emit active measurement signals according thereto; and a control device (5), which receives the measurement signals of the distance sensors (4-1, 4-2, 4-3) and determines an object distance (s) of detected objects (10). According to the invention, at least one distance sensor (4-1, 4-2, 4-3) additionally can be operated in an indirect operating mode in order to detect a detection signal emitted by another distance sensor (4-2, 4-3, 4-1) and reflected by the object (10) and in order to generate an indirect measurement signal.

Claims

1. Environment monitoring system (3) for a vehicle (1), the environment monitoring system (3) having:

at least two distance sensors (4-1, 4-2, 4-3) for detecting distances by measuring the propagation time of detection signals (9-1, 9-2), the distance sensors (4-1, 4-2, 4-3) each being in the form of a transmitting unit and receiving unit for the detection signal (9-1, 9-2, 11-1, 11-2) and, in a direct operating mode, each outputting detection signals (9-1, 9-2), receiving reflected components of the detection signals output by them and outputting active measurement signals (S1, S2) on the basis thereof, and

a control device (5) which receives the measurement signals (S1, S2, S3, S4) from the distance sensors (4-1, 4-2, 4-3) and determines an object distance (s) of detected objects (10),

characterized in that

at least one distance sensor (4-1, 4-2, 4-3) can be additionally operated in an indirect operating mode in order to detect a detection signal (11-2, 11-1) output by another distance sensor (4-2, 4-3, 4-1) and reflected by the object (10) and in order to generate an indirect measurement signal (S3, S4).

2. Environment monitoring system (3) according to claim 1, characterized in that it is in the form of a rear area monitoring system (3) of the vehicle (1) and is arranged on the rear (2) or in a rear region of the vehicle (1) in order to determine an object distance (s) between an object (10) in a rear area (7) behind the vehicle (1) and the rear area monitoring system (3) or the rear (2) of the vehicle (1).

3. Environment monitoring system according to claim 1 or 2, characterized in that the detection signals are ultrasonic waves (9-1, 9-2) or radar waves or light beams which can be output by the distance sensors (4-1, 4-2) into an emission angle region (8-1, 8-2).

4. Environment monitoring system (3) according to claim 3, characterized in that the emission angle regions (8-1, 8-2) of the distance sensors (4-1, 4-2) are directed rearwards and towards one another, with the result that they at least largely overlap in the rear area (7) behind the vehicle (1).

5. Environment monitoring system (3) according to claim 3 or 4, characterized in that the emission angle regions (8-1, 8-2) of the distance sensors (4-1, 4-2) are substantially in a horizontal plane and detect an angle range of greater than 45 degrees, preferably at least 60 degrees, in the plane.

6. Environment monitoring system according to one of the preceding claims, characterized in that each of the distance sensors (4-1, 4-2, 4-3) can be respectively operated in the following operating modes:

the direct operating mode in which the distance sensor (4-1, 4-2, 4-3) emits a detection signal (9-1, 9-2) and detects the detection signal (11-1, 11-2) reflected by an object (10) in order to determine a distance (L1, L2) as the half-way mark of the distance covered in the detection time between the emission time and the receiving time, and

the indirect operating mode in which the distance sensor (4-2, 4-1), without transmitting, passively receives the detection signal (11-1) emitted by another distance sensor (4-1) and reflected at an object (10) in order to determine a total distance (L1+L2) in an indirect measurement as the sum of the distances (L1, L2) between the two distance sensors (4-2, 4-1) and the object (10),

the transmitting distance sensor and the receiving passive distance sensor (4-1, 4-2, 4-3) being synchronized in the indirect operating mode in order to align the emission time and receiving time,

the further distance (L2) being able to be determined by the control device (5) by subtracting a distance (L1) determined in a direct measurement from a total distance (L1+L2) determined in an indirect measurement.

7. Environment monitoring system according to claim 6, characterized in that a combined operating mode is provided, in which a first distance sensor (4-1) transmits and receives in the direct operating mode and at least one second distance sensor (4-2), without transmitting, simultaneously passively receives reflections (11-1) of the detection signal (9-1) emitted by the first distance sensor (4-1) in the indirect operating mode.

8. Environment monitoring system according to claim 7, characterized in that the combined operating mode can be alternately carried out in such a manner that each distance sensor (4-1, 4-2) alternately transmits and receives and the other distance sensors (4-2, 4-1) simultaneously only passively receive.

9. Environment monitoring system according to one of the preceding claims, characterized in that one or more of the following further operating modes can be carried out:

radius estimation if only a single distance sensor (4-1, 4-2) receives a reflected detection signal (11-1, 11-2) in a direct measurement,

triangulation by means of direct measurements, in particular if indirect measurements are missing, by determining the individual direct distances (L1, L2) between the distance sensors (4-1, 4-2) and an object (10) using a known sensor distance (d),

back-up operating mode in which a plurality of, preferably all, distance sensors (4-1, 4-2, 4-3) simultaneously transmit and receive in order to increase the emitted total signal power and in order to estimate the object distance (s) between an object (10) and the rear area monitoring system (3),

in the case of only indirect measurements, the determination of the object distance (s) on an ellipse which forms the set of all points with the same sum of distances to the distance sensors (4-1, 4-2).

10. Environment monitoring system according to one of the preceding claims, characterized in that the control device (5) is intended to output synchronization signals (K1) to all distance sensors (4-1, 4-2, 4-3) in order to synchronize the distance sensors (4-1, 4-2, 4-3).

11. Environment monitoring system according to claim 10 and according To claim 8 or 9, characterized in that the control device (5) is connected to the distance sensors (4-1, 4-2, 4-3) via a bus, for example a LIN bus (6), and outputs synchronization signals (K1) for the combined operating mode,

the synchronization signals (K1) being addressed to all distance sensors (4-1, 4-2, 4-3) and containing, as a parameter, the statement of the distance sensor (4-1) transmitting in the direct operating mode.

12. Environment monitoring system according to one of the preceding claims, characterized in that precisely two distance sensors (4-1, 4-2) are provided and are fitted to the left-hand and right-hand lateral rear regions of the vehicle.

13. Environment monitoring system according to one of claims 1 to 11, characterized in that three distance sensors (4-1, 4-2, 4-3) are provided, a first distance sensor (4-1) of which is fitted to the left-hand lateral rear region, a second distance sensor (4-2) of which is fitted to the right-hand lateral rear region, and a third distance sensor (4-3) of which is fitted in the middle rear region of the vehicle.

14. Environment monitoring system according to one of the preceding claims, characterized in that two distance sensors (4-1, 4-2) are respectively provided in a plurality of planes lying above one another.

15. Method for determining an object distance (s) of an object (10), in particular using an environment monitoring system (3) according to one of the preceding claims,

in which at least two distance sensors (4-1, 4-2, 4-3)

each output detection signals (9-1, 9-2) and receive reflected components (11-1, 11-2) of the detection signals output by them in direct measurements, and

receive reflected detection signals (11-2, 11-1) which were output by another distance sensor (4-2, 4-3, 4-1) and were reflected by the object (10) in indirect measurements,

the object distance (s) being determined on the basis of at least one indirect measurement.