DE102014214927A1 - Radar system with backscatter transponder - Google Patents

Abstract

A radar system (10) for a vehicle (1), in particular a motor vehicle, comprises at least one transmitting / receiving unit (3) for radar signals (5) and at least one backscatter transponder which can be arranged on the vehicle (1) for determining the position of objects in the vehicle environment (8) (7.1, 7.2,..., 7.n-1, 7.n), which is set up, upon receipt of a radar signal (5) of the transceiver unit (3), a transponder signal (9) uniquely assignable to the backscatter transponder (7.1) ) back.

Description

The invention generally relates to measuring systems for detecting an environment of a vehicle. In particular, the invention relates to electronically scanning, based on the radar principle measuring systems for determining the position of objects in the environment of a vehicle. The invention also relates to vehicles.

Electronically scanning measuring systems for determining the position of objects by means of z. As RADAR (Radio Detecting and Ranging) or LIDAR (Light Detecting and Ranging) are known. Possible applications for these systems in vehicles are driver assistance systems, eg. As for the measurement of parking spaces, for adaptive control of vehicle speed, to assist in changing lanes, to control safety equipment before a collision, etc.

DE 10 2009 046 674 A1 shows, for example, a method and a device for supporting a parking operation of a motor vehicle in a parking position by means of a parking device, for example, a LIDAR sensor device is provided for detecting the contours of the parking position.

DE 10 2007 036 262 A1 shows a radar sensor for motor vehicles with a transmitting and receiving unit for microwaves and a beam shaping device which determines the directional characteristic of the transmitted and / or received microwave radiation in azimuth and in elevation.

A problem with the known radar-based systems used in the field of vehicles is that it may happen that the majority of the transmitted radar signal is not received again by the radar system, especially in particularly critical situations, such as vehicles passing each other at high speed. Therefore, the presence of objects possibly located in the vicinity of the vehicle (vehicle surroundings) can not be detected with the necessary reliability, in particular the distance and angle to such objects can not be measured correctly.

It is an object of the present invention to propose an improved radar system for a vehicle for determining the position of objects in the vehicle environment, with which in particular a more reliable location in the vehicle environment is possible.

The object is solved with the features of independent claim 1. Further developments will become apparent from the dependent claims, the description and the drawings.

In radar systems, direct and indirect reflections are difficult to distinguish. In addition, in the case of a directed reflection, radar waves are reflected in accordance with the law of reflection and, depending on the angle of radiation (illumination angle), do not arrive again at the location of the transmitting device. In addition, constructive and / or destructive interference can occur so that essential measurement information can be deleted or falsified.

According to the essence of the invention, to overcome u.a. the circumstances mentioned above, the basically known for vehicles radar systems by arrangement of so-called backscatter transponders (backscatter transponder, also called transponder for short here) on the vehicle. The transponders are set up to respond actively upon receipt of a radar signal with a clearly identifiable return signal (transponder signal). The transponder signal can then be received by the radar system and uniquely assigned to the transponder.

The arrangement of the individual transponders is basically arbitrary. Ie. the transponders do not necessarily have to be in a certain geometric arrangement, such. B. along a straight line and / or only horizontally, etc., be arranged on the vehicle. It is essential that the location of each individual, clearly identifiable transponder is known to the radar system. Thus, the radar system can detect more information both quantitatively and qualitatively than with known radar systems about the surroundings of the vehicle.

Several transponders can be distinguished for example on the basis of different modulation frequencies. For example, the transponder can be set up to modulate a received radar signal with a modulation signal assigned to the transponder and to re-radiate it as a return signal (transponder signal). Thus, depending on the radar principle used, it is possible to measure the distance to the respective transponder and accordingly also to an object in the vehicle environment.

Transponders located along the vehicle can also be used in Synthetic Aperture Radar (SAR) radar systems; As a result, the corresponding algorithms for environment detection can be additionally improved.

Finally, the transponder can also be used by other road users for a cheap protection by transponder z. B. are integrated into bicycles and school bags and these objects are thus reliably detectable and more accurate localized by the radar system of the vehicle. Accordingly, the transponders can also be used for marking landmarks (traffic signs, point-of-interest, POIs, etc.). The on-vehicle transponders can also be used for passive car-to-car (car2car) communication.

As a result, with the improvement proposed here, it is possible to better understand the environment of a vehicle. It can be dispensed with the integration of additional environment sensors. The backscatter transponders proposed here are also cheaper than the use of additional radar sensors.

The invention thus relates to a radar system for a vehicle, in particular a motor vehicle, for determining the position of objects in the vehicle environment with at least one transmitter / receiver unit for radar signals (radar device) and at least one backscatter transponder which can be arranged on the vehicle and which is set to transmit upon receipt of a radar signal - Reception unit to radiate a unique attributable to the backscatter transponder transponder signal.

Preferably, a plurality of backscatter transponders which can be arranged along an outer contour of the vehicle are provided. "Vehicle outer contour" here refers to a circumferential line of the vehicle in a plan view of the vehicle from above. The term "arranged along" means that the plurality of transponders are arranged substantially following the vehicle contour. For example, the backscatter transponders may be arranged at a regular or irregular interval along the sides of the vehicle with respect to a line parallel to the footprint of the vehicle (similar to a waterline on a ship). The backscatter transponders can be arranged, for example, along the right and left vehicle side of the vehicle. It is also possible the transponder with respect to the vehicle outer contour in a vertical direction, d. H. from top to bottom, to arrange. Of course, combinations of both variants, d. H. the horizontal and vertical arrangement, possible. Additionally arranged vertical transponders improve the resolution of the radar system in the elevation and improve the detection of vertical area targets.

The at least one backscatter transponder is preferably set up to radiate the transponder signal, which can be assigned to the backscatter transponder, omnidirectionally with respect to an arrangement location or assembly location on the vehicle in the vehicle surroundings. For example, a receiving or transmitting antenna of the transponder can be configured such that the desired emission characteristic or directional characteristic results in the half space. It is also possible to limit the emission characteristic of the transponder preferably as possible to a plane parallel to the footprint of the vehicle.

The at least one backscatter transponder preferably has a communication interface via which a uniquely identifiable property of the transponder signal can be set. The uniquely identifiable property may be a modulation frequency or a unique signature modulated onto the transponder signal. The at least one backscatter transponder can be connected, for example, to the communication interface with a control unit of the vehicle and / or with the transceiver unit of the radar system via a communication link, in particular a communication bus of the vehicle.

Backscatter transponders (also backscatter transponders) are known in principle. Such a backscatter transponder can be constructed substantially in the manner of the known RFID transponder. In other words, a transponder essentially has a receiving unit for electromagnetic signals of the frequency range of the radar signals, a transmitting unit for the transponder signal and optionally the communication interface. The transceiver's transmitting and receiving units may also be integrated into a single unit and share one or more antennas that are currently functioning as transmitting and receiving antenna (s) (monostatic antenna concept). As soon as the transponder receives a radar signal, it emits the transponder signal as a return signal via the transmitting unit. The transponder signal preferably uniquely identifies a transponder arranged on the vehicle.

The transponder can basically be a passive transponder that receives the necessary energy from the received radar signal. It may also be provided a connection for the supply of electrical energy from the vehicle or the radar system. The transponder can also be connected via the communication interface to a power source for power supply.

If the at least one transponder can be connected to a communication bus of the vehicle, the transponder can also have a communication unit which is used to communicate the transponder via the communication bus is set up. Thus, for example, the transponder signal assignable to the transponder can be set by the vehicle via the communication bus. For example, a modulation signal, for example a modulation frequency, can be set via the communication interface with which the transmission unit of the transponder modulates the transponder signal, as a unique signature which modulates the transmission unit to the transponder signal. This has the advantage that the transponder can be standardized and initially installed as desired, since the necessary unambiguous identification of the transponder by a configuration process on the part of the vehicle takes place only after arrangement on and connection to the vehicle. For example, a control unit of the vehicle's radar system can configure the individual transponders via the communication bus.

Depending on the radar principle used, it is possible with the electronically scanning, based on the radar principle measuring system for determining the position of objects in the vicinity of the vehicle to measure distances between the transmitting / receiving unit and the at least one transponder. Since the arrangement of the transmitting / receiving unit and the at least one transponder on the vehicle is known, the distance to an object adjacent to the vehicle, at which a radar signal of the transmitting / receiving unit is reflected and received by the respective transponder, can also be calculated.

In a development, the radar system has a plurality of backscatter transponders and a detection unit for detecting the vehicle surroundings. The detection unit may be configured to use the plurality of backscatter transponders to calculate a synthetic aperture of the radar system for the surroundings detection. The general principle of synthetic aperture systems is for the waveband of microwaves z. In "Radar with Real and Synthetic Aperture" by H. Klausing et al., Oldenbourg 2000, Chapter 8, p. 213 et seq. represented. Methods with synthetic aperture are also z. B. off WO 2006/072471 . DE 199 10 715 C2 or EP 0 550 073 B1 known.

In an advantageous development of the radar system, at least one further backscatter transponder external to the vehicle is provided, which can be arranged on a fixed or movable object. The transceiver unit of the vehicle can detect and localize the fixed or movable object marked therewith by means of the backscatter signal emitted by at least one further transponder external to the vehicle. Thus, for example, by means of additional backscatter transponders other road users are protected by better visibility. For example, a backscatter transponder can be integrated into bicycles or school bags. An object, such as a landmark or a so-called point-of-interest (POI) of a navigation system for automatic detection in the vehicle environment can also be marked with the at least one further backscatter transponder external to the vehicle. It could also be used to mark danger spots on the road (slippery roads, potholes, etc.).

In an advantageous development, the at least one backscatter transponder is set up for passive vehicle-to-vehicle communication. Communication between vehicles, in short car2car (C2C), is also referred to as vehicle2vehicle (V2V) or inter-vehicle (IV). The terms car2roadside (C2R), vehicle2roadside (V2R) and vehicle2infrastructure (V2I) are also used for communication between vehicles and their environment, in short car2x (C2X). The aforementioned communication in the vehicle is often called in-vehicle (InV). For example, between vehicles that are equipped with the radar system according to the invention, the radar systems could be used to avoid rear-end collisions and to trigger warnings and safety measures (activation of chassis and safety systems) from a collision (PreCrash functions). For example, rear-end collisions could be prevented by evaluating transponder signals originating from another vehicle (forward collision warning) by warning the driver when a critical situation is imminent on the basis of the available data. Alternatively, if a collision is unavoidable, optimal provision (airbags and / or seatbelt pretensioners, etc.) for the impending collision can be made on the basis of the information available.

The invention also relates to a backscatter transponder for use in one of the above-described embodiments of a radar system for a vehicle.

Finally, the invention is also suitable as part of the environmental sensor system of a driver assistance system with different subsystems, such as a parking assistant, blind spot monitoring or an adaptive cruise control (ACC) system.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, embodiments of the invention in Individual are described. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination. Likewise, the features mentioned above and further explained here can be used individually or in combination in any combination. Functionally similar or identical components or components are partially provided with the same reference numerals. The terms "left", "right", "top" and "bottom" used in the description of the embodiments refer to the drawings in an orientation with normally readable figure designation or normal readable reference numerals. The embodiments shown and described are not to be understood as exhaustive, but have exemplary character for explaining the invention. The detailed description is for the information of the person skilled in the art, therefore, in the description of known circuits, structures and methods are not shown or explained in detail in order not to complicate the understanding of the present description.

1 schematically illustrates a radar system for a vehicle with a plurality of arranged on the vehicle backscatter transponders.

2 schematically illustrates a traffic situation with a first vehicle 1 and a second vehicle 2 in traffic.

3 schematically illustrates a traffic situation with a first vehicle 1 and an object in the vehicle environment which is marked with a backscatter transponder for better visibility.

1 schematically illustrates a radar system 10 for a vehicle 1 for determining the position of objects, for example a polder 6 in the vehicle environment 8th ,

The radar system 10 has at least one radar device 3 with a transmitting unit 3.1 and a receiving unit (detection device) 3.2 for radar signals 5 and several on the vehicle 1 arranged, preferably in the outer surface integrated backscatter transponder 7.1 . 7.2 , ..., 7.n-1 . 7.n on. Of course, the radar device 3 be executed monostatically, ie the transmitting unit 3.1 and the receiving unit 3.2 are integrated as one unit and share group antennas as transmit and receive antennas. For simplified representation, only the transponder 7.1 . 7.2 , ..., 7.n-1 . 7.n indicated on the left side of the vehicle. On the right side of the vehicle are only the transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n corresponding phantom transponder indicated.

The backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n are along the vehicle outer contour 11 arranged on the perimeter of the vehicle 1 in the in 1 shown top view of the vehicle 1 from above corresponds. The backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n can thereby along a to the footprint of the vehicle 1 parallel line can be arranged at the vehicle sides at regular intervals; "Arranged along" means that the multiple transponders of the vehicle outer contour 11 are arranged following.

The transmitting unit 3.1 is set up to radiate radar beams in the microwave range (microwaves) as radar signals and to the receiving unit 3.2 equipped as a detection device by means of which can be determined for received radar signals azimuth and elevation. That is, the radar device 3 can determine the receive direction for each reflected radar signal. That is, the radar device 3 is the direction from which a received microwave signal comes.

The radar device 3 For example, by the from the DE 10 2007 036 262 A1 be realized known radar sensor for motor vehicles. In addition, it should be noted that the radar device 3 the environment is not scanned with a single beam or a "radar lobe", but the entire coverage area or even several predetermined areas by means of multiple array antennas that serve as both transmit antennas and as receiving antennas (monostatic antenna concept), irradiated with microwaves. The array antennas are arranged at a small distance from each other. By means of the array antennas, the respective phase offset (phase difference) of the individual microwaves received by the individual array antennas can be detected. This can be the radar device 3 determine the respective receiving angle for a microwave reflected on an object. In current radar systems in the vehicle sector, this is usually implemented only horizontally, ie there is no real altitude measurement (elevation), if anything at the receiving end, instead.

The applied measuring principle is usually the known monopulse method whose deficits can be compensated with the radar system proposed here.

Each of the backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n For example, the transponder 7.n-1 , is set up in response to receiving a radar signal 5 the transmitting unit 3.1 towards a unique transponder 7.n-1 assignable transponder signal 9 reflect back. The transponder signal 9 then runs on the way of the radar signal 5 back to the radar device 3 , At the radar device 3 it gets from the receiving unit 3.2 receive. The example shows the transponder signal 9 also at the polder 6 reflects and runs from there to the receiving unit 3.2 , The backscatter transponder 7.n-1 is set up, that the backscatter transponder 7.n-1 uniquely assignable transponder signal 9 with respect to the vehicle 1 in the vehicle environment 8th to broadcast omnidirectionally.

The backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n each have a communication interface 13 , via which a clearly identifiable property of the transponder signal 9 is adjustable. For clarity, the communication interface is only on the transponder 7.n-1 characterized.

The backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n are each with a control unit 15 of the vehicle 1 via a communication connection in the form of a communication bus 17 For example, a Flex bus or CAN bus, the vehicle 1 connected. The control unit 15 is set up, among other things, the uniquely identifiable property of the transponder signal 9 of the transponder 7.n-1 via a control command to the communication interface 13 transferred to. Accordingly, the transponder signals may be individual to each of the backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n be set.

The backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n can also each directly with the send / receive unit 3 of the vehicle 1 over the communication bus 17 be connected.

During operation of the radar system, as soon as one of the backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n a radar signal receives, from this backscatter transponder the transponder signal that uniquely identifies it 9 radiated. This can be done, for example, by modulating the radar device originally 3 emitted microwave signal. The modulation may also include the transmission time of the transponder signal. For unambiguous identification of the transponder signal, ie for an unambiguous assignment to one of the backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n , is from the control unit 15 the modulation frequency at which the transponder modulates the transponder signal set. In other words, basically all backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n built the same and can therefore be installed anywhere on the vehicle during the installation of the radar, in particular in anyway required functional elements, such as a rearview mirror integrated. The described unique identification of each of the backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n is done by a configuration process on the part of the control unit 15 or the radar device 3 , That is, the initially identical backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n be from the control unit 15 of the radar system 10 of the vehicle 1 over the communication bus 17 individually configured.

Depending on the radar principle used, it is with the radar system 10 possible, the position of an object, such as the polder 6 in the environment 8th of the vehicle 1 To better determine the distances between the radar device 3 and the respective transponder are clearly measurable. Because the relative arrangement of the radar device 3 and the backscatter transponder 7.1 . 7.2 , ..., 7.n-1 . 7.n at the vehicle 1 can be known, distances based on a received transponder signal 9 from the control unit 15 or an associated registration unit for the environment 8th of the vehicle 1 be calculated.

2 shows a typical traffic situation with a first vehicle 1 and a second vehicle 2 in traffic with, for example, two lanes. The first vehicle 1 drives to the right of the second vehicle 2 , The first vehicle 1 has that on the basis of 1 explained radar system 10 ,

In 2 is seen that much of the radar signal 5 not again to the radar device 3 is backblasted. Instead, many of the radar signals are due to multiple reflections between and at the two vehicles 1 and 2 distracted. As a result, especially in such critical situations, much of the radar signal 5 not again from the radar device 3 receive. Thus, only a moderate presence detection can be done and the distance and the direction to the second vehicle 2 can not be reliably measured. In 2 it can be seen that due to the transponder signal 9 that from the backscatter transponder 7.n-1 is emitted, a sufficiently strong signal at the radar device 3 Will be received. In addition, since the relative location of the system components is known, the distance to the second vehicle 2 be clearly determined.

3 schematically illustrates a traffic situation with a first vehicle 1 and a bike 6.1 as an object in the vehicle environment 8th , For better and especially automatic recognition is the bike 6.1 with a to the radar system 10 of the vehicle 1 external backscatter transponder 7.Ex marked. According to the principle explained above, the backscatter transponder 7.Ex set up to receive a radar signal 5.1 the radar device 3 of the vehicle 1 out in response to a transponder signal 9.1 radiate. Because the backscatter transponder 7.Ex no component of the radar system 10 of the vehicle 1 is, is the transponder signal 9.1 not by the control unit 15 of the vehicle configurable. Therefore, the backscatter transponders used in this way 7.Ex be provided with a possibly generally agreed identifier that allows at least one unique assignment to an object class (here: bicycle).

In an analogous manner, this can be done on the basis of 3 explained principle for improving the detection and localization of the vehicle 1 External objects are transferred to any other both movable and fixed objects. It is an advantageous application of the principle, for example, landmarks or points of interest (POI) in cooperation with a navigation system of the vehicle 1 to mark by means of a backscatter transponder.

Another not shown advantageous use of the radar system 10 consists in an improved detection and modeling of the vehicle environment 8th , For this purpose, a correspondingly configured detection unit (not shown) for detecting the vehicle surroundings with the radar system 10 be set up, the multiple backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n for calculating a synthetic aperture for the radar system 10 to use. This allows the sampling resolution of the radar system 10 be significantly improved.

Yet another not shown use of the radar system 10 This is the multiple backscatter transponders 7.1 . 7.2 , ..., 7.n-1 . 7.n for a passive vehicle-to-vehicle (car2car) communication, for example for collision avoidance, PreCrash sequencing etc.

,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009046674 A1 [0003]
• DE 102007036262 A1 [0004, 0036]
• WO 2006/072471 [0023]
• DE 19910715 C2 [0023]
• EP 0550073 B1 [0023]

Cited non-patent literature

• "Radar with Real and Synthetic Aperture" by H. Klausing et al., Oldenbourg 2000, Chapter 8, p. 213 et seq. [0023]

Claims (11)

Radar system ( 10 ) for a vehicle ( 1 ), in particular a motor vehicle, for determining the position of objects in the vehicle environment ( 8th ) with at least one transmitting / receiving unit ( 3 ) for radar signals ( 5 ) and at least one on the vehicle ( 1 ) can be arranged backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ), which is set up, upon receipt of a radar signal ( 5 ) of the transceiver unit ( 3 ) a unique to the backscatter transponder ( 7.1 ) assignable transponder signal ( 9 ) back. Radar system ( 10 ) according to claim 1, characterized in that there are several along an outer contour ( 11 ) of the vehicle ( 1 ) can be arranged backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) having. Radar system ( 10 ) according to claim 1 or 2, characterized in that the at least one backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) arranged to the backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) assignable transponder signal ( 9 ) with respect to a location on the vehicle ( 1 ) in the vehicle environment ( 8th ) radiate omnidirectionally. Radar system ( 10 ) according to one of the preceding claims, characterized in that the at least one backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) a communication interface ( 13 ), via which a clearly identifiable property of the transponder signal ( 9 ) is adjustable. Radar system ( 10 ) according to claim 4, characterized in that the uniquely identifiable property is a unique modulation signal, in particular a modulation frequency or a signature of the transponder signal ( 9 ). Radar system ( 10 ) according to one of the preceding claims, characterized in that the at least one backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) with a control unit ( 15 ) or with the transceiver unit ( 3 ) of the vehicle ( 1 ) via a communication connection ( 17 ), in particular a communication bus of the vehicle ( 1 ), is connectable. Radar system ( 10 ) according to one of the preceding claims, characterized in that the radar system ( 10 ) multiple backscatter transponders ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) and a detection unit for detecting the vehicle environment ( 8th ), which is set up, the plurality of backscatter transponders ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) for calculating a synthetic aperture of the radar system ( 10 ) to use. Radar system ( 10 ) according to any one of the preceding claims with at least one other to the vehicle ( 1 ) external backscatter transponder ( 7.Ex ) attached to a fixed object, such as a landmark, a point-of-interest, or moving object ( 6.1 ), for example another road user, can be arranged. Radar system ( 10 ) according to one of the preceding claims, characterized in that the plurality of backscatter transponders ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) are arranged for a passive vehicle-to-vehicle communication. Backscatter transponder ( 7.1 . 7.2 , ..., 7.n-1 . 7.n ) for use in a radar system ( 10 ) according to one of claims 1 to 9. Vehicle, in particular motor vehicle, comprising a radar system ( 10 ) according to one of claims 1 to 9.

Images