DE102015004468A1 - Method for operating a driver assistance system and motor vehicle - Google Patents

Abstract

Method for operating a driver assistance system of a motor vehicle (1), which has at least one radar sensor (2) which records the environment of the motor vehicle (1), wherein position information of a front and a rear rim (20) of the at least one road user detected in the radar data Traffic participants are determined from the radar data and from the position information a relative orientation of the road user to the motor vehicle (1) is determined, the relative orientation is taken into account by at least one function of the driver assistance system.

Description

The invention relates to a method for operating a driver assistance system of a motor vehicle, which has at least one radar sensor which records the surroundings of the motor vehicle. In addition, the invention relates to a motor vehicle.

Driver assistance systems for motor vehicles have been proposed in the prior art in a variety of configurations. Driver assistance systems use for at least one function input data describing circumstances in and / or around one's own motor vehicle and can evaluate these, for example, against measures criteria in the fulfillment of which the driver assistance system performs a measure, for example a driving intervention, an information output, in particular a warning to the driver , and / or the adaptation of operating parameters of another vehicle system. The input data are often (possibly pre-evaluated) sensor data of various sensors of the motor vehicle, with respect to the environment of the motor vehicle related driver assistance systems and thus also of environmental sensors. A frequently used in the context of driver assistance systems sensor is a radar data on the environment of the motor vehicle-supplying radar sensor.

The use of radar sensors in motor vehicles is already widely known in the art. Radar sensors are nowadays usually used as environment sensors for a medium and large distance range in order to determine other road users or larger objects in distance, angle and relative speed. Such radar data can enter into environmental models or even be made available to vehicle systems directly. Benefits of radar data draw in the prior art, for example, longitudinal guidance systems, such as ACC, or security systems.

Radar sensors of conventional design usually have a greater extent and are rather clunky, after the antennas and the electronic components required directly on the antenna, so the radar front end, are integrated in a housing. Mainly the electronic components thereby form the radar transceiver, which contains a frequency control (usually comprising a phase-locked loop - PLL), mixing devices, a low noise amplifier (LNA) and the like, but often also control modules and digital signal processing components are realized close to the antenna, for example already processed Sensor data, such as object lists, on a connected bus, such as a CAN bus to give.

The realization of semiconductor-based radar components has long proved difficult, as expensive specialty semiconductors, particularly GaAs, have been required. Smaller radar sensors have been proposed, whose entire radar frontend is realized on a single chip in SiGe technology before solutions in CMOS technology became known. Such solutions are the result of extending CMOS technology to high frequency applications, often referred to as RF CMOS. Such a CMOS radar chip is realized extremely compact and does not use expensive special semiconductors, thus offers significant advantages over other semiconductor technologies, especially in the production. An exemplary implementation of a 77 GHz radar transceiver as a CMOS chip is described in the article by Jri Lee et al., "A Fully Integrated 77GHz FMCW Radar Transceiver in 65nm CMOS Technology", IEEE Journal of Solid State Circuits 45 (2010), pp. 2746-2755 , described.

After it has also been proposed to realize the chip and the antenna in a common package, a very low cost small radar sensor is possible, which can meet the space requirements significantly better and due to the short signal paths also has a very low signal-to-noise ratio and for high frequencies and larger, variable frequency bandwidths is suitable. Therefore, such small-sized radar sensors can also be used for short-range applications, for example in the range of 30 cm to 10 m.

It has also been proposed to provide such a CMOS transceiver chip and / or a package with CMOS transceiver chip and antenna on a common circuit board with a digital signal processing processor (DSP processor) or the functions of the signal processing processor in the CMOS Integrate transceiver chip. Similar integration is possible for control functions.

Especially in safety systems as a typical example of driver assistance systems, the detection of dynamic and static targets in the environment of one's own motor vehicle plays an important role. Depending on recognized objects in the environment of the motor vehicle and their properties, an evaluation of the traffic situation can then be carried out, which in turn, as already indicated, can lead to measures, for example a warning for the driver. It was proposed to avoid false and / or false warnings in more complex traffic situations in a preliminary stage for the evaluation of Measure criteria to perform a situation analysis (SITA) of the current traffic situation. With the SITA, a large number of data describing the current traffic situation, in particular also radar data, can be used to provide a good basis for the actual algorithm evaluating warning criteria.

In particular, when considering possible collision scenarios, but also in other functions, not only the position of other road users to own motor vehicle is a relatively important information in the evaluation of a traffic situation, but also the orientation of the other road users relative to their own motor vehicle. If, for example, another road user travels parallel to his own motor vehicle, it is difficult to measure the orientation of the road user relative to his own motor vehicle. In today's known evaluation of the radar data, the distributed reflections on the surface of the road user are interpreted, which, however, do not make it possible to deduce the orientation of the road user. Therefore, usually, for example, for blind spot monitoring systems that monitor the blind spot of the motor vehicle, only a presence detection is performed and made the basis of a warning information to be issued to the driver. However, a sound assessment of criticality is not yet available.

The invention is therefore based on the object of specifying a possibility for improved environmental monitoring based on radar data.

To solve this problem, it is provided according to the invention in a method of the type mentioned that for at least one detected in the radar data road user position information of a front and a rear rim of the road user from the radar data are determined and from the position information relative orientation of the road user to the motor vehicle is determined, wherein the relative orientation is taken into account by at least one function of the driver assistance system.

The invention is based on the combination of two findings. On the one hand, it is now possible to use radar sensors in motor vehicles, particularly in the context of the radar technologies already discussed at the outset, which, despite their space-saving size, can reproduce the location of a reflection in high-resolution. For example, the use of radar sensors within the scope of the present invention is conceivable which offer a spatial resolution of less than 5 cm, in particular less than 3.5 cm. This makes it possible to resolve even smaller structures in the radar data and to detect accordingly. So far so far radar data mainly the presence of objects, be they static or dynamic objects, have reproduced as such, it is now possible to resolve even properties, especially substructures, these objects and to use appropriate.

It has been shown that a particularly well detectable and usable substructure of other road users, especially other motor vehicles, is given by the rims. Studies have shown that the rims represent the main scattering centers of the reflections on the lateral surface of a road user, in particular a target vehicle. The availability of modern radar sensors in motor vehicles makes it possible to resolve the location of these main scattering centers relatively accurately. This allows by separate interpretation of the rim reflection of target vehicles, not only better to dissolve the relative position of the other road user, but also to determine the orientation of the road user to own motor vehicle. The thus determined orientation of other road users can be expediently used to improve a situation analysis of the current traffic situation by a driver assistance system.

The method described here thus allows a better interpretation of the current traffic situation by taking into account the positioning and orientation of the own motor vehicle relative to detected road users. Critical traffic situations, in particular with regard to imminent side collisions, can be detected earlier and more reliably, so that a punctual measure, in particular a warning of the driver, can take place. For example, it can be provided that threshold values are adapted in measure criteria for warning the driver depending on the orientation of the road user to his own motor vehicle. Of course, another consideration of the relative orientation of the road user is conceivable. Overall, a more reliable execution of functions of the driver assistance systems is given by the improved possible situation analysis of a current traffic situation, which in particular also makes it possible to reduce the false and false alarm rate.

As has already been mentioned, the method according to the invention is particularly suitable for applications in which the other road users are in parallel travel, in particular in the longitudinal region also occupied by the motor vehicle itself, after only for those cases in which ambient sensors only provide a lateral view of the vehicle Road user was possible, one Determination of orientation was not possible reliably. If, for example, a motor vehicle is traveling next to one's own motor vehicle, it is possible purely on the basis of the radar data to determine a relative position, by making use of the reflective properties of the rims, which are visible in a side view. The method according to the invention thus makes it possible, in particular, to replenish the previous gaps in the detection possibilities resulting from parallel travel at the same height.

As position information, at least one transverse support of the rims to a longitudinal axis of the own motor vehicle can be determined. If both transverse bins intended for a road user are the same, the road user is oriented parallel to his own motor vehicle. Other orientations result from which cross-stock is larger than the other one. From transverse shelves, for example, an angle can be determined, in which the other road user stands for his own motor vehicle. This is useful, for example, when considering scenarios of parallel travel, in particular in dead-angle applications. Of course, the position information may also include further information, for example, a longitudinal shelf with respect to a transverse axis of the motor vehicle and the like.

As already mentioned, it has been found that the rims are the main reflective targets on the side surface of other motor vehicles, ie road users. Consequently, the rims in the radar data can expediently be detected as the main reflection centers in a region containing radar data of the road user, which relates in particular to a side view. It is already known how individual reflection events that are contained in the radar data, in particular in the context of a pre-evaluation, a specific object, here a road user, can be assigned. After using a high-resolution radar sensor, a reflection-covered area is created in which the main reflection centers (main scattering centers) can be easily located by appropriate analysis algorithms. Conventional processing algorithms for segmenting road users into radar data are already known; For the detection of the rims, in particular, algorithms from the image processing can also be transferred to the radar data after they are present in a specific spatial resolution as a kind of "image" of the road user. Major reflection centers may also be determined by viewing intensity traces or the like.

As already mentioned, the invention exploits the knowledge of new, high-resolution, modern radar technologies. A particularly advantageous embodiment of the present invention can provide that a radar sensor with a radar transceiver realized by a semiconductor chip, in particular a CMOS chip, is used. It is particularly advantageous in this context if, in addition to the radar transceiver, a digital signal processing component (DSP) and / or a control unit of the radar sensor are realized by the semiconductor chip and / or an antenna arrangement of the radar sensor with the semiconductor chip is realized as a package. In this way, extremely small-sized, easily accommodated in the motor vehicle radar sensors can be created, which also allow an excellent signal-to-noise ratio due to the short signal paths. With such semiconductor-based radar sensors, in particular CMOS-based, it is also possible to realize operation at high frequencies and with a high frequency bandwidth.

Particularly in the case of a radar sensor realized within the technology, but also generally, it is extremely expedient in this context if the radar sensor is in a frequency range from 77 to 81 GHz and / or with a frequency bandwidth greater than 1 GHz, in particular 4 GHz, is operated.

A high-resolution radar system with 4 GHz bandwidth can achieve a very high distance resolution, for example of approximately 3.4 cm, relative to conventional, previously used automotive radar sensors. The resolution also correlates with the distance measurement accuracy, which means that with higher resolution, the accuracy is very high. As a result, for example, the transverse rests of the rims, but also the position information in general, can be measured very accurately.

An expedient development of the invention provides that several, in particular eight, radar sensors are used, which completely cover the surroundings of the motor vehicle in a 360 ° angle range. For example, it is possible to use an array of eight radar sensors, of which three can each be installed in the front and in the rear bumper. Two further, laterally oriented radar sensors can, for example, be provided in doors of the motor vehicle, in particular by providing a radar-permeable, paintable window in the door panel. Since the multiple radar sensors are expediently wide-angle radar sensors, for example with an opening angle of up to 170 °, for example 160 °, in the azimuth and up to 120 °, for example 90 °, in the elevation, the entire environment becomes reliably covered around the motor vehicle. The side-facing radar sensors are particularly relevant when looking at the same height driving parallel road users. However, of course, a use of the method for other road users, such as road users, conceivable, for which then the front or rear radar sensors are more relevant.

In an expedient embodiment, a safety system can be used as driver assistance system, wherein the relative orientation is taken into account in the determination of a collision value describing a possible collision with the respective road user. For example, the determined relative orientation of another road user can thus be used if his future trajectory is to be extrapolated or otherwise estimated. In this case, a main application area, as already explained, is parallel driving, so that the security system is, in particular, a blind spot monitoring system, for example a blind spot detector. By evaluating the orientation of a target vehicle relative to its own motor vehicle, the warning can be triggered dynamically and early in the event of an impending lateral collision with a road user traveling in parallel at the same height as his own motor vehicle, if a situation that is particularly critical due to the relative orientation is recognized.

It should be noted at this point that the inventive method does not necessarily have to be performed by a (exclusively) the driver assistance system associated control unit, but especially in the case of several relative orientation using functions of different driver assistance systems, a central control unit may be provided, which then preferably the Sensor data, including the radar data, various environmental sensors of the motor vehicle evaluates to provide already suitable input data for the various functions available, for example in the form of an environment model, as has already been proposed in principle in the prior art. If the environment model is object-oriented, other road users, for example, can be assigned their relative orientations directly there. If the control unit presupposing the sensor data also carries out the functions, it is also possible to speak of a "central driver assistance system" which realizes a plurality of functions of individual sub-driver assistance systems.

In addition to the method, the invention also relates to a motor vehicle, comprising at least one driver assistance system and a control unit designed to carry out the method according to the invention. All statements relating to the method according to the invention can be analogously transferred to the motor vehicle according to the invention, with which also the advantages already mentioned can be obtained.

Further advantages and details of the present invention will become apparent from the embodiments described below and with reference to the drawing. Showing:

1 a schematic diagram of a motor vehicle according to the invention,

2 a radar sensor used in the motor vehicle,

3 a first sketch for measuring a relative orientation in a first traffic situation, and

4 a second sketch for measuring a relative orientation in a second traffic situation.

1 shows a schematic diagram of a motor vehicle according to the invention 1 , This has eight radar sensors in the present case 2 on, which are designed as wide-angle radar sensors and, as indicated by the indicated detection areas 3 it can be seen, a 360 ° detection of the environment of the motor vehicle 1 allow. Here are the radar sensors 2 realized on the basis of CMOS technology extremely small construction, for example, less than 3 cm by 3 cm, so they in the front and rear bumper 4 . 5 of the motor vehicle 1 can be installed and also a shoring in side doors 6 is possible, for example, if a radar-permeable window is provided in the sheet.

Radar data of radar sensors 2 be in a control unit 7 which is assigned to a driver assistance system, in this case a blind spot monitoring system, and is also designed to carry out the method according to the invention.

2 shows in the form of a schematic diagram of the structure of the radar sensors 2 more accurate. A radar sensor 2 has a housing 8th on, in which a circuit board 9 is held on a semiconductor chip 10 , here a CMOS chip, is arranged. The semiconductor chip 10 is common with an antenna arrangement 11 of the radar sensor 2 as a package 12 realized, wherein the antenna arrangement 11 is configured so that angles to a reflective point in two mutually perpendicular planes can be detected.

Through the semiconductor chip 10 are present in addition to the radar transceiver 13 also a digital signal processing component 14 (DSP) and a control unit 15 of the radar sensor 2 realized.

The radar sensors 2 are operated in a frequency range of 77 to 81 GHz at a frequency bandwidth of 4 GHz in order to high-resolution the environment of the motor vehicle 1 to provide descriptive radar data.

In the control unit 7 These radar data are now evaluated to the relative orientation of other road users to own motor vehicle 1 to be able to determine. For this purpose, in the region assigned to the respective road user, in which reflections of the road user have been received, the main scattering centers, in particular in the lower area, are sought, which correspond to the rims of the destination vehicle as road users. Different types of algorithms can be used, which evaluate, for example, intensity profiles or are also based on image processing algorithms. After the radar sensors 2 have a high spatial resolution, especially in the range of 3.5 cm, the positions of the rims can be determined quite accurately. From the transverse trays to the longitudinal axis of the motor vehicle, the relative orientation then results, which can be used for functions of driver assistance systems, in particular of the mentioned blind spot monitoring system, as will be explained in more detail below.

The 3 and 4 show exemplary traffic situations in which to the motor vehicle 1 another motor vehicle 16 is in parallel, thus at the same height in substantially the same or a similar direction as the motor vehicle 1 Is on the way. In this case, the longitudinal axis and direction of the own motor vehicle 1 With 17 denotes the longitudinal axis and direction of travel of the other motor vehicle 16 as a road user with 18 , It is evident in 3 a case shown in which the motor vehicles 1 . 16 completely parallel to each other.

The one on the right side of the motor vehicle 1 provided, here only by the detection area 3 indicated radar sensor 2 detects a side view of the motor vehicle 16 , where reflection centers 19 are marked by stars. Most reflection events in the area of the rims become apparent 20 of the motor vehicle 16 measured. The rims 20 form the main reflection centers. By appropriate evaluation of the radar data, the distances r11 and r21 from the radar sensor 2 to the rims 20 to be determined, according to which, based on the known installation location, the lateral deposits f11 and f21 from the longitudinal axis are used as position information 17 of the motor vehicle 1 can be determined. In the case of 3 f11 = f21, that means the motor vehicles 1 . 16 drive exactly parallel and there is no particularly critical situation.

4 shows a further case in which, as with the longitudinal axis 18 of the second motor vehicle 16 can be seen, this no longer exactly parallel to the motor vehicle 1 drives, but is oriented to this. Thus, it can be determined in the analysis of the radar data after determination of the position information that f22> f12 holds, what exactly this relative orientation of the motor vehicle 16 describes. Extrapolating the trajectories of motor vehicles 1 . 16 in the case of 4 , there will be a higher probability of collision than in the case of 3 yield; the driving situation is therefore more critical.

This can be mapped, for example, by lowering a threshold value to be exceeded for triggering the warning in a measure criterion for warning the driver, and thus warns earlier by the blind spot monitoring system. However, the relative orientation already preferably enters into the situation analysis (SITA), thus allowing a better calculation of collision variables related to a possible collision, so that a more reliable collision can therefore be concluded with greater certainty and accordingly more reliably and early in the event of critical situations Blind spot monitoring system can be warned.

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 non-patent literature

• Jri Lee et al., "A Fully Integrated 77GHz FMCW Radar Transceiver in 65nm CMOS Technology", IEEE Journal of Solid State Circuits 45 (2010), pp. 2746-2755 [0005]

Claims (10)

Method for operating a driver assistance system of a motor vehicle ( 1 ), which at least one the environment of the motor vehicle ( 1 ) descriptive radar data radar sensor ( 2 ), characterized in that for at least one road user detected in the radar data position information of a front and a rear rim ( 20 ) of the road user are determined from the radar data and from the position information a relative orientation of the road user to the motor vehicle ( 1 ), wherein the relative orientation is taken into account by at least one function of the driver assistance system. A method according to claim 1, characterized in that as position information at least one transverse support of the rims ( 20 ) to a longitudinal axis ( 17 ) of the own motor vehicle ( 1 ) is determined. Method according to claim 1 or 2, characterized in that the rims ( 20 ) are detected in the radar data as the main reflection centers in an area, in particular on a side view, containing radar data of the road user. Method according to one of the preceding claims, characterized in that a radar sensor ( 2 ) with a through a semiconductor chip ( 10 ), in particular CMOS chip, realized radar transceiver ( 13 ) is used. Method according to Claim 4, characterized in that in addition to the radar transceiver ( 13 ) also a digital signal processing component ( 14 ) and / or a control unit ( 15 ) of the radar sensor ( 2 ) through the semiconductor chip ( 10 ) and / or an antenna arrangement ( 11 ) of the radar sensor ( 2 ) with the semiconductor chip ( 10 ) as a package ( 12 ) is realized. Method according to one of the preceding claims, characterized in that the radar sensor ( 2 ) is operated in a frequency range of 77 to 81 GHz and / or with a frequency bandwidth greater than 1 GHz, in particular of 4 GHz. Method according to one of the preceding claims, characterized in that several, in particular eight, radar sensors ( 2 ) are used, which the environment of the motor vehicle ( 1 ) completely cover in a 360 ° angle range. Method according to one of the preceding claims, characterized in that a safety system is used as driver assistance system, wherein the relative orientation is taken into account in the determination of a collision value describing a possible collision with the respective road user. A method according to claim 8, characterized in that the security system is a blind spot monitoring system. Motor vehicle ( 1 ), comprising at least one radar sensor ( 2 ), at least one driver assistance system and a control device (especially for the driver assistance system and / or central), which is designed to carry out the method according to one of the preceding claims ( 7 ).

Images