DE102018213169A1 - RADAR CROSS-SECTION (RCS) MONITOR FOR DETECTION OF RESTRICTION - Google Patents

Abstract

Disclosed are a method using a radar cross-section (RCS) monitor for restriction detection, a system using the RCS monitor for restriction detection, a computer program that performs the method using the RCS monitor for restriction detection, and a vehicle that uses the system using the RCS limiter detection limiter. An RCS value for a short-range scan and / or an RCS value for a long-range scan for stable objects are determined. A deviation value of the RCS value of the short-range scan and / or a deviation value of the RCS value of the long-range scan is calculated for each stable object based on a change between the respective RCS values of a current cycle and the respective RCS values of previous cycles. An RCS monitor is calculated based on the deviation values. It is then determined based on a change in the RCS monitoring element of the current cycle in relation to the RCS monitoring element of the previous cycles whether the radar sensor is restricted.

Description

The present invention relates to a method and system using a radar cross-section (RCS) monitoring element for restriction detection, and a computer program which carries out the method using the RCS monitoring element for restriction detection, and to a vehicle which uses the system to use the RCS monitoring element Restriction detection includes.

Modern vehicles and in particular vehicles with driver assistance systems (ADAS) such as adaptive cruise control (ACC) and autonomous vehicles include radar sensors for observing the surroundings of the vehicle. In the present context, the term “environment” should in particular be an environment around the radar sensor or the vehicle up to a predetermined or variable distance of preferably up to 300 meters, more preferably up to 250 meters, very particularly preferably up to 200 meters and especially up to 150 meters. A radar sensor has a field of view (FoV) in which the radar sensor can detect objects or, in other words, see them. The presence of a restriction due to foreign substances or foreign material can reduce the visibility as well as the accuracy and reliability of the radar sensors. The visibility of a radar sensor is its ability to detect objects within the radar sensor's FoV. These foreign substances can be caused, for example, by environmental conditions such as temperature / temperature gradient, moisture, ice, dirt, rain or the like. The restriction can reduce the performance or even prevent the radar sensors from operating properly.

Such a reduction in performance or prevention of proper operation is monitored by analyzing the visibility of each radar sensor. This is done using a statistical approach to visibility with regard to stable objects in the FoV of each radar sensor. A stable object is a static or dynamic object that is detected by a radar sensor over a certain predetermined period of time with a certain predetermined accuracy. For this purpose, a probability of existence is determined. An object can be classified as a stable object if the probability of its existence is greater than or equal to 0.99. The probability of existence can be calculated by setting a probability of existence of a newly detected object to 0.5. The probability can be increased in each cycle if the same object is detected again and otherwise reduced. The probability of existence can be increased or decreased in steps of 0.01. The accuracy of the detection of an object is based on a variance or a standard deviation of detection data for the respective object from the respective radar sensor. The visibility of a radar sensor is indicated by the maximum distance within which a stable object can be detected by the radar sensor. Three histograms are created and analyzed for the statistical approach to visibility. A first histogram contains information about dynamic or moving objects, a second histogram contains information about static or stationary objects and a third histogram contains information about the first and last detection of each object. The mean values of each histogram are combined and the visibility of the respective sensor is determined on the basis of the combined mean values. If the visibility is below a predetermined threshold value, a reduction in the visibility or performance of the respective radar sensor is specified.

In a vehicle with adaptive cruise control (ACC vehicle), an algorithm of the radar sensors regulates an acceleration of the vehicle. This regulation is based on the detection of objects or vehicles in front of the ACC vehicle. The acceleration must be regulated so that the ACC vehicle follows a vehicle in front with a sufficient distance between the ACC vehicle and the vehicle in front (sufficient space to interrupt in a dangerous situation or the like). Especially under difficult weather conditions such as heavy rain, the radar sensor can lose the object corresponding to the vehicle in front and there is a risk of a collision. The above-described indication of reducing visibility is used to trigger a return of control of the vehicle to the driver, so that the driver is responsible for avoiding a collision under difficult weather conditions.

However, recognizing such a reduction in visibility with the three histograms in the statistical approach can be difficult. Especially if the performance of the radar sensor decreases rapidly (e.g. due to heavy rain), a further improvement in the representation or confirmation of this decrease in performance is necessary in the statistical approach. There is therefore a need for a more reliable and faster detection of restrictions from radar sensors.

The object of the present invention is to improve the restriction detection or the detection of a reduction in the visibility of radar sensors by providing a method using a radar cross-section (RCS) monitoring element for restriction detection according to independent claim 1 and a system using the RCS monitoring element for restriction detection and a computer program that uses the method Carries out RCS monitoring element for restriction detection, and a vehicle, which comprises the system using the RCS monitoring element for restriction detection, according to the further independent claims. Further developments of the present invention are the subject of the dependent claims.

• - Erfassen stabiler Objekte (O_i) mit dem Radarsensor in Zyklen (k). Die Zyklen (k) umfassen einen Nahbereichsscan und einen Fernbereichsscan mit dem Radarsensor.
• - Ermitteln eines RCS-Werts für den Nahbereichsscan (RCS_i,Nah ^k) und/oder eines RCS-Werts für den Fernbereichsscan (RCS_i,Fern ^k) für jedes stabile Objekt (O_i) für jeden Zyklus (k).
• - Berechnen eines Abweichungswerts des RCS-Werts des Nahbereichsscans (DeltaRCS_i,Nah ^k) und/oder eines Abweichungswerts des RCS-Werts des Fernbereichsscans (DeltaRCS_i,Fern ^k) für jedes stabile Objekt (O_i) für jeden Zyklus (k) basierend auf einer Veränderung zwischen den jeweiligen RCS-Werten (RCS_i,Nah ^k, RCS_i,Fern ^k) des Zyklus (k) und den jeweiligen RCS-Werten (RCS_i,_Nah ^k-x, RCS_i,Fern ^k-x) der vorherigen Zyklen (k-x). x ist hier größer gleich 1.
• - Berechnen eines RCS-Überwachungsglieds (DeltaRCSÜberwachungsglied^k) des Zyklus (k) basierend auf den Abweichungswerten (DeltaRCS_i,Nah ^k, DeltaRCS_i,Fern ^k) des jeweiligen Zyklus (k) .
• - Feststellen, ob eine Einschränkung des Radarsensors vorliegt, basierend auf einer Änderung des RCS-Überwachungsglieds (DeltaRCSÜberwachungsglied^k) des Zyklus (k) bezogen auf das RCS-Überwachungsglied (DeltaRCSÜberwachungsglied^k-x) der vorherigen Zyklen (k-x). x ist hier größer gleich 1.

According to a first aspect of the present invention, a method for restriction detection for a radar sensor using a radar cross section (RCS) monitoring element comprises the following steps:

• - Detection of stable objects (O _i ) with the radar sensor in cycles (k). The cycles (k) include a short-range scan and a long-range scan with the radar sensor.
• - Determining an RCS value for the short-range scan (RCS _{i, near} ^k ) and / or an RCS value for the long-range scan (RCS _{i, far} ^k ) for each stable object (O _i ) for each cycle (k).
• - Calculate a deviation value of the RCS value of the short-range scan (DeltaRCS _{i, near} ^k ) and / or a deviation value of the RCS value of the far-range scan (DeltaRCS _{i, far} ^k ) for each stable object (O _i ) for each cycle (k) on a change between the respective RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) of the cycle (k) and the respective RCS values (RCS _i , _Nah ^kx , RCS _{i, Fern} ^kx ) of the previous cycles ( k). x is greater than or equal to 1 here.
• - Calculating an RCS monitoring element (DeltaRCS monitoring element ^k ) of the cycle (k) based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) of the respective cycle (k).
• - Determine whether the radar sensor is restricted based on a change in the RCS monitoring element (DeltaRCS monitoring element ^k ) of the cycle (k) in relation to the RCS monitoring element (DeltaRCS monitoring element ^kx ) of the previous cycles (kx). x is greater than or equal to 1 here.

All steps or a part of the steps can or can also be carried out in parallel.

According to a second aspect of the present invention, a system for detecting a restriction for a radar sensor using an RCS monitoring element is set up in such a way that it carries out the steps of the previously described method.

• Für jeden Zyklus (k):
  • - Erfassen stabiler Objekte (O_i) mit dem Radarsensor unter Verwendung eines Nahbereichsscans und eines Fernbereichsscans mit dem Radarsensor.
  • - Ermitteln eines RCS-Werts für den Nahbereichsscan (RCS_i,Nah ^k) und/oder eines RCS-Werts für den Fernbereichsscan (RCS_i,Fern ^k) für jedes stabile Objekt (O_i).
  • - Berechnen eines Abweichungswerts des RCS-Werts des Nahbereichsscans (DeltaRCS_i,Nah ^k) und/oder eines Abweichungswerts des RCS-Werts des Fernbereichsscans (DeltaRCS_i,Fern ^k) für jedes stabile Objekt (O_i) basierend auf einer Veränderung zwischen den jeweiligen RCS-Werten (RCS_i,Nah ^k, RCS_i,Fern ^k) des aktuellen Zyklus (k) und den jeweiligen RCS-Werten (RCS_i,Nah ^k-x, RCS_i,Fern ^k-x) der vorherigen Zyklen (k-x). x ist hier größer gleich 1.
  • - Berechnen eines RCS-Überwachungsglieds (DeltaRCSÜberwachungsglied^k) basierend auf den Abweichungswerten (DeltaRC-S_i,Nah ^k, DeltaRCS_i,Fern ^k).
  • - Feststellen, ob eine Einschränkung des Radarsensors vorliegt, basierend auf einer Änderung des RCS-Überwachungsglieds (DeltaRCSÜberwachungsglied^k) des aktuellen Zyklus (k) bezogen auf das RCS-Überwachungsglied (DeltaRCSÜberwachungsglied^k-x) der vorherigen Zyklen (k-x). x ist hier größer gleich 1.

According to a third aspect of the present invention, a computer program carries out the previously described method for detecting a restriction for a radar sensor using an RCS monitoring element and comprises the following steps:

• For each cycle (k):
  • - Detection of stable objects (O _i ) with the radar sensor using a short-range scan and a long-range scan with the radar sensor.
  • - Determining an RCS value for the short-range scan (RCS _{i, near} ^k ) and / or an RCS value for the long-range scan (RCS _{i, far} ^k ) for each stable object (O _i ).
  • - Calculating a deviation value of the RCS value of the short-range scan (DeltaRCS _{i, near} ^k ) and / or a deviation value of the RCS value of the far-range scan (DeltaRCS _{i, far} ^k ) for each stable object (O _i ) based on a change between the respective ones RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) of the current cycle (k) and the respective RCS values (RCS _{i, Nah} ^kx , RCS _{i, Fern} ^kx ) of the previous cycles (kx). x is greater than or equal to 1 here.
  • - Calculating an RCS monitoring element (DeltaRCS monitoring element ^k ) based on the deviation values (DeltaRC-S _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ).
  • - Determine whether there is a restriction of the radar sensor based on a change in the RCS monitoring element (DeltaRCS monitoring element ^k ) of the current cycle (k) in relation to the RCS monitoring element (DeltaRCS monitoring element ^kx ) of the previous cycles (kx). x is greater than or equal to 1 here.

According to a fourth aspect of the present invention, a vehicle comprises the system for the restriction detection for a radar sensor as described above using an RCS monitoring element. The vehicle also includes one or more radar sensors. The restriction detection system is set up here so that it detects a restriction for each radar sensor of the vehicle.

The stable objects (O _i ) are detected in each cycle (k) of the radar sensor. One cycle of the radar sensor includes a long-range scan and a long-range scan. The radar sensor uses a low power for the short-range scan radiated. The radar sensor emits high power for the long-range scan. With the close-range scan at low power, objects in the vicinity of the radar sensor can be detected. In this connection, is located within a distance of approximately 0.20 m to 70 m. With the long-range scan at high power, objects far away from the radar sensor can be detected. In this connection, it lies far away within a distance of approximately 0.20 m to 170 m. A field of view (FoV) for the short-range scan can range from -45 ° [degrees] to +45 ° and a FoV for the long-range scan can range from -9.0 ° to +9.0 °. The radar sensor can detect a position of an object in the FoV of the short-range scan and / or in the FoV of the long-range scan. The position of an object can be specified by a distance to the radar sensor and an angle with respect to a normal axis or center line of the radar sensor, which runs parallel to a beam direction or radiation direction through a center point of the radar sensor.

By foreign substances or foreign material, e.g. B. caused by environmental conditions such as temperature / temperature gradient, moisture, ice, dirt, rain or the like, the visibility in the FoV of the radar sensor may be restricted. Such a restriction can exist in the area of the short-range scan or in the area of the long-range scan or in both. For example, the short-range scan may be restricted, but the long-range scan may not. The RCS value for the short-range scan (RCS _{i, near} ^k ) of a stable object (O _i ) would change as a result of the restriction, whereas the RCS value for the short-range scan (RCS _{i, Fern} ^k ) of another stable object (O _i ) would not change due to this limitation. Conversely, this also applies to a restriction that only affects the long-range scan.

The short-range scan and the long-range scan collect objects that are present in the FoV of the radar sensor. A detection is classified here as a stable object (O _i ) if the detection is given over a predetermined number of cycles (k) and if the detection has a predetermined accuracy. A detection can be classified as a stable object if the probability of its existence is greater than or equal to 0.99. The probability of existence can be calculated by setting a probability of existence of a newly detected object to 0.5. The probability can be increased in each cycle (k) if the same object is detected again, and otherwise reduced. The probability of the presence can be increased or decreased in steps of 0.01 per cycle (k).
Only stable objects (O _i ) are tracked. In addition, only RCS values of stable objects (O _i ) are taken into account for the restriction detection.

• - das Material, aus dem das Objekt gefertigt ist;
• - die absolute Größe des Objekts, die relative Größe des Objekts bezogen auf die Wellenlänge, die von dem Radarsensor emittiert wird;
• - der Einfallswinkel, unter dem der Radarstrahl auf einen bestimmten Abschnitt des Objekts auftrifft, der von der Form des Objekts sowie seiner Ausrichtung zum Radarsensor abhängt;
• - der Reflexionswinkel, unter dem der reflektierte Strahl den Teil des Objekts verlässt, auf den er aufgetroffen ist, der von dem Einfallswinkel und der Polarisation der ausgesendeten abhängt, und
• - die Empfangsstrahlung bezogen auf die Ausrichtung des Objekts. Zwar sind die Stärke der emittierten Strahlung und die Entfernung des Objekts zum Radarsensor bei der Erfassung von Objekten von Bedeutung, jedoch sind es keine Faktoren, die die Berechnung des RCS-Werts beeinflussen, da der RCS eine Eigenschaft des Reflexionsvermögens des Objekts ist. Der RCS-Wert kann quantitativ berechnet werden als: $$RCS=4\pi R^2\frac{P_{sc}}{P_{ir}}=4\pi R^2\frac{{\left|E_{sc}\right|}^2}{{\left|E_{ir}\right|}^2}$$
  
  wobei R die Entfernung zwischen dem Radarsensor und dem Objekt ist, P_ir die eingestrahlte Leistungsdichte auf dem Objekt ist und P_sc die gestreute Leistungsdichte ist oder E_ir die eingestrahlte Feldstärke und E_sc die gestreute Feldstärke ist.

The RCS value is a measure of how well an object can be detected by the radar sensor. A higher RCS value indicates that an object is easier to detect. A limited amount of radar energy is reflected or scattered by an object in the FoV of the short-range scan and / or in the FoV of the long-range scan back to the radar sensor. The factors influencing this include:

• - the material from which the object is made;
• - the absolute size of the object, the relative size of the object in relation to the wavelength emitted by the radar sensor;
• - The angle of incidence at which the radar beam strikes a specific section of the object, which depends on the shape of the object and its orientation to the radar sensor;
• the angle of reflection at which the reflected beam leaves the part of the object it has struck, which depends on the angle of incidence and the polarization of the emitted, and
• - The received radiation related to the orientation of the object. Although the strength of the emitted radiation and the distance of the object to the radar sensor are important when detecting objects, they are not factors that influence the calculation of the RCS value, since the RCS is a property of the reflectivity of the object. The RCS value can be calculated quantitatively as: $$RCS=4\pi R^2\frac{P_{sc}}{P_{ir}}=4\pi R^2\frac{{\left|e_{sc}\right|}^2}{{\left|e_{ir}\right|}^2}$$
  
  where R is the distance between the radar sensor and the object, P _{ir is} the radiated power density on the object and P _{sc is} the scattered power density or E _{ir is} the radiated field strength and E _{sc is} the scattered field strength.

wobei P die von einem stabilen Objekt (O_i) empfangene Leistung in dB ist, K eine Kombinationskonstante aus allen konstanten Faktoren aus der Radargleichung ist, R die radiale Entfernung des stabilen Objekts (O_i) in dB ist und D eine Dämpfung bedingt durch eine sekundäre Fläche wie eine Stoßstange ist, in der der Radarsensor angeordnet ist.The RCS value for the short-range scan (RCS _i , _near ^k ) and / or the RCS value for the long-range scan (RCS _{i, far} ^k ) are calculated here in dB [decibels] according to the following equation: $$RC{S}_{\left(i.NaH|Fern\right)}^k=P-K+4R+D$$

where P is the power received from a stable object (O _i ) in dB, K is a combination constant of all constant factors from the Radar equation is, R is the radial distance of the stable object (O _i ) in dB and D is an attenuation due to a secondary surface like a bumper, in which the radar sensor is arranged.

The RCS values for the short-range scan (RCS _{i, near} ^k ) and the RCS values for the long-range scan (RCS _i , _far ^k ) are determined and stored for the stable objects (O _i ). The RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) can be stored in a memory. A memory can be a data storage device such as a magnetic data storage device / working memory (e.g. magnetic core storage device, magnetic tape, magnetic card, magnetic stripe, magnetic bubble storage device, drum storage device, hard disk drive, floppy disk or removable storage device), an optical data storage device / working storage device (e.g. holographic storage device, optical tape, tesa tape, laser disc, phase writer (phase writer dual, PD), compact disc (CD), digital video disc (DVD), high definition DVD (HD DVD), Blu-ray disc (BD) or ultra density Optical (UDO)), a magneto-optical data memory / working memory (e.g. MiniDisc or Magneto-Optical Disk (MO disk)), a volatile semiconductor memory / electronic memory (e.g. direct access memory (RAM), dynamic RAM ( DRAM) or Static RAM (SRAM)), a non-volatile semiconductor memory / electronic memory (e.g. read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), flash EEPROM (e.g. USB stick), fer ro-electric RAM (FRAM), magnetoresistive RAM (MRAM) or phase change RAM) or a data carrier / medium.

The deviation values of the RCS values of the short-range scan and / or the RCS values of the long-range scan (DeltaRCS _{i, near} ^k , DeltaRCS _{i, far} ^k ) are calculated for each cycle. This can be done using a simple differential quotient of the respective current RCS value and the previous RCS value or by determining a derivative using a different numerical method using the RCS values of several previous steps.

The RCS monitoring element (DeltaRCS monitoring element ^k ) is calculated on the basis of the deviation values of the RCS values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ). B. by determining an average of the RCS values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ).

A specific RCS monitoring element (DeltaRCS monitoring element ^k ) is determined for each cycle (k). Based on a change or change in the RCS monitor (DeltaRCS monitor ^k ) of the current cycle (k) related to the RCS monitor (DeltaRCS monitor ^k-1 , DeltaRCS monitor ^kx ) of the previous cycle (k-1) or several previous cycles (kx ) a restriction is determined. A restriction is recognized here if the change or change lies above a predetermined threshold value. This threshold can be between about 5 dB and 10 dB, where 5 dB can result from a partial restriction that leads to a deterioration of the visibility and 10 dB can result from a complete restriction that leads to a complete loss of quality of the visibility , In particular, if a stable object (O _i ) can no longer be detected, instead of using the statistical approach with a range monitoring element, a timeout monitoring element and an object loss monitoring element, the RCS monitoring element (DeltaRCS monitoring element) is used exclusively or in addition to the statistical approach ^k ) used to determine whether there is a restriction or whether the object has simply disappeared from the FoV of the short-range scan and or the FoV of the long-range scan of the radar sensor.

The determination based on the RCS monitor (DeltaRCS monitor ^k ) is faster than the determination based on the range monitor, the timeout monitor and the object loss monitor. Furthermore, the determination is more precise, since no or not only the statistical approach is used, so that a rapidly decreasing performance of the radar sensor z. B. can be detected due to heavy rain.

• - einer Zieldichte des Objekts (O_i), eine Mindestgrenze kann 192 oder in 8-Bit-Darstellung 1100 0000 betragen, wo das Objekt in den letzten zwei Zyklen erfasst wird;
• - davon, ob das Objekt (O_i) real ist;
• - davon, ob das Objekt (O_i) verdeckt ist;
• - davon, ob sich das Objekt (O_i) ganz in der Nähe befindet;
• - einer Lebensdauer des Objekts (O_i);
• - einer relativen Quergeschwindigkeit des Objekts (O_i) und/oder
• - einem Winkel des Objekts (O_i).

A further development of the present invention comprises determining a weight (w _i ) for each stable object (O _i ) on the basis of at least:

• a target density of the object (O _i ), a minimum limit can be 192 or, in 8-bit representation, 1100 0000, where the object has been detected in the last two cycles;
• - whether the object (O _i ) is real;
• - whether the object (O _i ) is covered;
• - whether the object (O _i ) is very close;
• - a lifetime of the object (O _i );
• - a relative transverse speed of the object (O _i ) and / or
• - an angle of the object (O _i ).

As a result, the calculation of the RCS monitoring element (DeltaRC monitoring element ^k ) is also based on the weights (w _i ).

Normally, a stable object (O _i ) or deviation values of the RCS values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) of the stable object (O _i ) with a weight (w _i ) of 1 are set. When determining a restriction, the most important object is a stable object (O _i ) immediately in front of the radar sensor or the vehicle with such a radar sensor. A stable object (O _i ) at an angle of approximately 0 ° with respect to the normal axis of the radar sensor is thus assigned a higher weight (w _i ) than a stable object (O _i ) at an angle other than 0 °. The weight (w _i ) of a stable object at an angle other than 0 ° can here be reduced to less than 1 and / or the weight (w _i ) of a stable object (O _i ) at an angle of approximately 0 ° can be reduced to more than 1 increase. Likewise, a respective weight (w _i ) of more than 1 can be assigned to a stable object (O _i ) that is real and / or not covered and / or is very close, and / or a stable object (O _i ) that is not real and / or is covered and / or is not very close, a respective weight (w _i ) of less than 1 can be assigned. In this context, very close means within approximately a maximum distance of 20 m to the radar sensor. Furthermore, the density of a stable object (O _i ) can be taken into account, so that a stable object (O _i ) with a density above a predetermined threshold value has a respective weight (w _i ) of more than 1 and below the threshold value a respective weight (w _i ) is assigned from less than 1. The density threshold can be 192. Even if the lifespan of the object (O _i ) is short and / or the relative transverse speed of the object (O _i ) is high, the respective weight (w _i ) can be reduced to less than 1 and vice versa. In this context, a high relative transverse speed is a speed of greater than or equal to 6 m / s [meters per second].

By assigning weights (w _i ) to the stable objects (O _i ) based on the properties, the accuracy of the RCS monitoring element (DeltaRCS monitoring element ^k ) and the precision in deciding whether there is a restriction can be improved further, since more meaningful data means a stronger one Influence the decision.

According to a development of the present invention, the calculation of the RCS monitoring element (DeltaRCS monitoring element ^k ) comprises determining a histogram of the deviation values (DeltaRC-S _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) by recognizing a respective class of each stable object (O _i ) in a field of view (FoV) of the radar sensor.

A distribution of the deviation values of the stable objects (O _i ) for the short-range scan and / or the long-range scan (DeltaRCS _{i, near} ^k , DeltaRCS _{i, far} ^k ) is calculated as a histogram. The histogram can have a class width of 6.25 dB and 16 classes between -40 dB and +60 dB. With the mean value of the histogram, a decision can be made as to whether the radar sensor is restricted. A stable object (O _i ) has a specific deviation value or gradient (DeltaRCS _{i, Nah} ^k , DeltaRC-S _{i, Fern} ^k ), which is different from its RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) current cycle (k) and the previous cycle or cycles (k-1, kx). For example, a car has an RCS value (RCS _{i, Nah} ^k or RCS _{i, Fern} ^k ) of approximately 10 dB and a moped has an RCS value (RCS _{i, Nah} ^k or RCS _{i, Fern} ^k ) of approximately 5 dB on. The gradients or deviation values of the stable objects (O _i ) for the short-range scan and / or the long-range scan (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) are inserted into the histogram. A weight (w _i ) as described above can also be applied to these gradients or deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ). If the mean of the histogram is approximately 0 dB, a constraint loss of a stable object (O _i ) is unlikely and otherwise such a constraint loss is more likely. The RCS monitoring element (DeltaRCS monitoring element ^k ) can be determined on the basis of this probability of a restriction of the radar sensor. The FoV of the radar sensor is a combined FoV, which consists of the FoV of the short-range scan and the FoV of the long-range scan.

Using a histogram is a particularly simple and quick way of determining whether the radar sensor is restricted.

A further development of the present invention comprises calculating at least one mean value, a variance, a standard deviation and / or a confidence based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) of the cycle (k) and the deviation values (DeltaRCS _{i, Nah} ^kx , DeltaRCS _{i, Fern} ^kx ) of the previous cycles (kx). x here is greater than or equal to 1. Furthermore, the calculation of the RCS monitoring element (DeltaRCS monitoring element ^k ) is based on at least the mean, the variance, the standard deviation and / or the confidence.

Apart from the mean value of the deviation values of the stable objects (O _i ) for the short-range scan and / or the long-range scan (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) or the histogram, the variance and / or standard deviation and / or confidence can used in deciding whether a Radar sensor restriction. If an average of the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) or the histogram is close to 0 dB and there is also a high confidence and / or low variance and / or low standard deviation, then the probability for the Loss of a stable object (O _i ) due to damping due to a restriction of the radar sensor is low. Otherwise, the probability of losing the stable object (O _i ) is high.

With the additional consideration of the variance and / or the standard deviation and / or the confidence, the decision-making process is more precise than without it.

A further development of the present invention comprises filtering at least the mean value, the variance, the standard deviation and / or the confidence. Furthermore, the calculation of the monitoring element (DeltaRCS monitoring element ^k ) is based at least on the filtered mean value, the filtered variance, the filtered standard deviation and / or the filtered confidence.

A bandpass filter or a lowpass filter or a combination of these filters is applied to the mean and / or the variance and / or the standard deviation and / or the confidence. Noise and other unwanted signals can thus be suppressed.

With the additional filtering, the calculated monitoring element (DeltaRCS monitoring element ^k ) is more precise by avoiding unwanted signals.

According to a development of the present invention, the stable objects (O _i ) are dynamic objects or static objects.

The objects detected with the short-range scan and / or the long-range scan in a cycle (k) of the radar sensor can be static objects such as traffic signs, trees, curbs etc. and / or dynamic objects such as vehicles, pedestrians etc.

According to a development of the present invention, the vehicle also includes driver assistance systems (ADAS).

An ADAS such as an automatic interruption assistant, which informs a driver of the vehicle about a required interruption maneuver, such as an emergency interruption, is dependent on information about the position and relative speed of objects in the vicinity of the vehicle.

The decision as to whether a radar sensor is restricted thus improves the reliability of such ADAS systems.

According to a development of the present invention, the vehicle further comprises an adaptive cruise control (ACC).

An ACC is in particular when the vehicle is controlled automatically, e.g. automatically braked when a collision with an object is likely depends on information from the radar sensors about objects in the vicinity of the vehicle.

The decision as to whether a radar sensor is restricted thus improves the reliability of the ACC.

According to a development of the present invention, the vehicle is an autonomous vehicle.

Autonomous vehicles are controlled without the influence of a human driver. Information about the environment of the autonomous vehicle and in particular about objects in this environment are therefore disadvantageous for any decision regarding the control of the automatic vehicle.

The decision as to whether a radar sensor is restricted thus improves the reliability of autonomous vehicles.

In the present context, the term “environment” should in particular be understood as an environment around the ego vehicle up to a predetermined, or variable, distance of preferably up to 300 meters, more preferably up to 250 meters, very particularly preferably up to 200 meters and in particular can be understood up to 170 meters.

• 1 zeigt vereinfacht ein Ablaufdiagramm für ein Verfahren unter Verwendung eines Radarquerschnitt(RCS)-Überwachungsglieds zur Einschränkungserkennung.
• 2 zeigt vereinfacht ein Computerprogramm 20, das das Verfahren unter Verwendung des RCS-Überwachungsglieds zur Einschränkungserkennung durchführt, das in 1 dargestellt ist.
• 3A-B zeigen vereinfacht Histogramme von RCS-Werten.
• 4A-B zeigen vereinfacht Histogramme von Abweichungswerten.
• 5 zeigt vereinfacht ein System unter Verwendung des RCS-Überwachungsglieds zur Einschränkungserkennung.
• 6 zeigt vereinfacht ein autonomes Fahrzeug, das das System unter Verwendung des RCS-Überwachungsglieds zur Einschränkungserkennung umfasst, das in 5 dargestellt ist.

The present invention and its technical field are explained in more detail below with an exemplary embodiment which is illustrated in the drawing. The exemplary embodiment only contributes to a better understanding of the present invention and should in no way be interpreted as a restriction on the scope of the present invention. In particular, it is possible to extract aspects of the object described in the figure and to combine it with other components and findings from the present description or figure, unless it is expressly described otherwise. The same reference numerals designate the same objects, so that explanations from other figures can be used in addition.

• 1 shows simplified a flowchart for a method using a radar cross-section (RCS) monitoring element for restriction detection.
• 2 simply shows a computer program 20 which performs the method using the RCS restriction detection monitor described in 1 is shown.
• 3A-B simply show histograms of RCS values.
• 4A-B simply show histograms of deviation values.
• 5 simply shows a system using the RCS monitor for restriction detection.
• 6 simply shows an autonomous vehicle that includes the system using the RCS constraint detection monitor that is shown in FIG 5 is shown.

In 1 is simplified a flowchart for a method 10 using a radar cross-section (RCS) monitoring element for restriction detection.

In one acquisition step 11 stable objects O _i are detected with a radar sensor in cycles k. The cycles k include a short-range scan and a long-range scan with the radar sensor. The stable objects O _i are detected in every cycle k of the radar sensor. The stable objects O _i are static objects such as traffic signs, curbs, trees etc. and dynamic objects such as vehicles (cars, motorcycles, mopeds, bicycles etc.), pedestrians etc. A cycle of the radar sensor comprises a post-range scan and a far-range scan. A low power is emitted by the radar sensor for the short-range scan. A field of view (FoV) for the short-range scan has a range from -45 ° [degrees] to +45 °. With the short-range scan at low power, objects within the FoV for the short-range scan and within a distance of approximately 0.20 m [meters] to 70 m to the radar sensor can be detected. The radar sensor emits high power for the long-range scan. A FoV for the long-range scan has a range from -9.0 ° to +9.0 °. With the long-range scan at high power, objects can be detected within the FoV for the long-range scan and within a distance of approximately 0.20 m to 170 m to the radar sensor. The radar sensor detects a position of an object in the FoV of the short-range scan and / or in the FoV of the long-range scan. The position of an object is specified by a distance to the radar sensor and an angle with respect to a normal axis or center line of the radar sensor, which runs parallel to a beam direction or radiation direction through a center point of the radar sensor.

• - einer Zieldichte des Objekts O_i;
• - davon, ob das Objekt O_i real ist;
• - davon, ob das Objekt O_i verdeckt ist;
• - davon, ob sich das Objekt O_i ganz in der Nähe befindet;
• - einer Lebensdauer des Objekts O_i;
• - einer Relativgeschwindigkeit des Objekts O_i und/oder
• - einem Winkel des Objekts O_i.

Normalerweise wird ein stabiles Objekt O_i mit einem Gewicht w_i von 1 angesetzt. Bei der Ermittlung einer Einschränkung ist das wichtigste Objekt ein stabiles Objekt O_i unmittelbar vor dem Radarsensor beziehungsweise dem Fahrzeug mit einem derartigen Radarsensor. Einem stabilen Objekt O_i unter einem Winkel von ungefähr 0° bezogen auf die Normalachse des Radarsensors wird somit ein höheres Gewicht w_i zugewiesen als einem stabilen Objekt O_i unter einem anderen Winkel als 0°. Das Gewicht w_i eines stabilen Objekts unter einem anderen Winkel als 0° kann hier auf unter 1 reduziert werden und/oder das Gewicht w_i eines stabilen Objekts O_i unter einem Winkel von ungefähr 0° kann auf über 1 erhöht werden. Ebenso wird einem stabilen Objekt O_i, das sich ganz in der Nähe befindet, ein jeweiliges Gewicht w_i von über 1 zugewiesen und/oder wird einem stabilen Objekt O_i, das sich nicht ganz in der Nähe befindet, ein jeweiliges Gewicht w_i von unter 1 zugewiesen. In diesem Zusammenhang bedeutet ganz in der Nähe innerhalb von ungefähr einer Entfernung von maximal 20 m zum Radarsensor.In an optional investigation step 11.1 a weight w _{i is determined} for each stable object O _i on the basis of at least:

• a target density of the object O _i ;
• - whether the object O _{i is} real;
• - whether the object O _{i is} covered;
• - whether the object O _{i is} very close;
• - a lifetime of the object O _i ;
• - a relative speed of the object O _i and / or
• - an angle of the object O _i .

A stable object O _i with a weight w _i of 1 is normally used. When determining a restriction, the most important object is a stable object O _i immediately in front of the radar sensor or the vehicle with such a radar sensor. A stable object O _i at an angle of approximately 0 ° with respect to the normal axis of the radar sensor is thus assigned a higher weight w _i than a stable object O _i at an angle other than 0 °. The weight w _{i of} a stable object at an angle other than 0 ° can here be reduced to less than 1 and / or the weight w _{i of} a stable object O _i at an angle of approximately 0 ° can be increased to more than 1. Similarly, a stable object O _i, which is located very close to, a respective weight w _i of about 1 assigned and / or a stable object O _i, which is not very close, a respective weight w _i of assigned under 1. In this context, very close means within approximately a maximum distance of 20 m to the radar sensor.

wobei P die von einem stabilen Objekt O_i empfangene Leistung in dB ist, K eine Kombinationskonstante aus allen konstanten Faktoren aus der Radargleichung ist, R die radiale Entfernung des stabilen Objekts O_i in dB ist und D eine Dämpfung bedingt durch eine sekundäre Fläche wie eine Stoßstange ist, in der der Radarsensor angeordnet ist. Die Gewichte w_i können bei der Berechnung der RCS-Werte RCS_i,Nah ^k, RCS_i,Fern ^k ebenfalls berücksichtigt werden.In one investigative step 12 an RCS value for the short-range scan RCS _{i, near} ^k and / or an RCS value for the long-range scan RCS _{i, far} ^{k is determined} for each stable object O _i for each cycle k. The RCS value for the short-range scan RCS _{i, near} ^k and / or the RCS value for the long-range scan RCS _{i, far} ^k are calculated here in dB [decibels] according to the following equation: $$RC{S}_{\left(i.NaH|Fern\right)}^k=P-K+4R+D$$

where P is the power received by a stable object O _i in dB, K is a combination constant of all constant factors from the radar equation, R is the radial distance of the stable object O _i in dB and D causes damping through a secondary surface like a bumper in which the radar sensor is located. The weights w _i can also be taken into account when calculating the RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^k .

In one calculation step 13 a deviation value of the RCS value of the short-range scan DeltaRCS _{i, Nah} ^k and / or a deviation value of the RCS value of the short-range scan DeltaRCS _{i, Fern} ^k for each stable object (O _i ) for each cycle (k) based on one Change between the respective RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) of the cycle (k) and the respective RCS values (RCS _i , _Nah ^kx , RCS _{i, Fern} ^kx ) of the previous cycles (kx) calculated. x here is greater than or equal to 1. For each cycle, the deviation values of the RCS values of the short-range scan and / or the RCS values of the long-range scan (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) are calculated using a simple differential quotient of the current RCS Value and the previous RCS value or by determining a derivative using another numerical method using the RCS values of several previous steps.

In an optional calculation step 13.1 at least one mean, a variance, a standard deviation and / or a confidence based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) of the cycle (k) and the deviation values (DeltaRC-S _{i, Nah} ^kx , DeltaRCS _{i, Fern} ^kx ) of the previous cycles (kx) are calculated. x is greater than or equal to 1. Here, apart from the mean value of the deviation values of the stable objects (O _i ) for the short-range scan and / or the long-range scan (DeltaRCS _{i, near} ^k , DeltaRCS _{i, far} ^k ), the variance and / or standard deviation can and / or confidence can be used in deciding whether the radar sensor is restricted.

In an optional filter step 13.2 at least the mean, the variance, the standard deviation and / or the confidence are filtered. A bandpass filter or a lowpass filter or a combination of these filters is applied to the mean and / or the variance and / or the standard deviation and / or the confidence. Noise and other unwanted signals can thus be suppressed.

In one calculation step 14 an RCS monitoring element DeltaRCS monitoring element ^{k of} the cycle k is calculated based on the deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^{k of} the respective cycle k. A specific RCS monitoring element DeltaRCS monitoring element ^{k is} determined for each cycle k. The calculation of the RCS monitoring element DeltaRCS monitoring element ^k can also be based on the weights w _i . The weights w _i are taken into account expressly or implicitly in the calculation of the RCS monitoring element DeltaRCS monitoring element ^k . The weights w _i can be taken into account during the determination of the RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^k or during the calculation of the deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k and thus implicitly in the calculation of the RCS Monitoring element DeltaRCS monitoring element ^{k are} taken into account. The calculation of the RCS monitoring element DeltaRCS monitoring element ^k can also be based on at least the (filtered) mean value, the (filtered) variance, the (filtered) standard deviation and / or the (filtered) confidence. To calculate the RCS monitoring element DeltaRCS monitoring element ^k , a histogram of the deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^{k can be} determined by recognizing a respective class of each stable object O _i in the FoV of the radar sensor, which is a combination of the FoV of the short-range scan and the FoV of the long-range scan. The histogram can have a class width of 6.25 dB and 16 classes between -40 dB and +60 dB. A stable object O _i has a specific deviation value or gradient DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k , which is based on its RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^k in the current cycle k and the previous cycle or depends on the previous cycles k-1, kx. For example, a car has an RCS value RCS _{i, Nah} ^k or RCS _{i, Fern} ^k of approximately 10 dB and a moped has an RCS value RCS _{i, Nah} ^k or RCS _{i, Fern} ^k of approximately 5 dB. The gradients or deviation values of the stable objects O _i for the short-range scan and / or the long-range scan DeltaRC-S _{i, Nah} ^k , DeltaRCS _i , _Fern ^k are inserted into the histogram. A weight w _i as described above can also be applied to these gradients or deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k . If the average of the histogram is approximately 0 dB, a constraint loss of a stable object O _{i is} unlikely, and otherwise such a constraint loss is more likely. The RCS monitoring element DeltaRCS monitoring element ^k can be determined on the basis of this probability of a restriction of the radar sensor. The FoV of the radar sensor is a combined FoV, which consists of the FoV of the short-range scan and the FoV of the long-range scan. If a (filtered) mean value of the deviation values DeltaRC-S _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k or the histogram is close to 0 dB and also a high (filtered) confidence and / or low (filtered) variance and / or low (filtered) ) There is or is a standard deviation, the probability of losing a stable object O _i due to damping due to a restriction of the radar sensor is low. Otherwise, the probability of losing the stable object O _{i is} high.

In one step 15 based on a change in the RCS monitoring element DeltaRCS monitoring element ^{k of} the cycle k with respect to the RCS monitoring element DeltaRCS monitoring element ^{kx of} the previous cycles kx, it is determined whether there is a restriction of the radar sensor, x is greater than or equal to 1. Here, on the basis of a change or change in the A restriction is determined for the RCS monitoring element DeltaRC-S monitoring element ^{k of} the current cycle k in relation to the RCS monitoring element DeltaRCS monitoring element ^k-1 , DeltaRCS monitoring element ^{kx of} the previous cycle k-1 or several previous cycles kx. With the mean value of the histogram of the deviation values DeltaRCS _{i, Nah} ^k , DeltaRC-S _{i, Fern} ^k , the RCS monitoring element DeltaRCS monitoring element ^k can be determined and a decision can be made as to whether the radar sensor is restricted. A restriction is recognized here if the change or change lies above a predetermined threshold value. This threshold can be between about 5 dB and 10 dB, where 5 dB can result from a partial restriction that leads to a deterioration of the visibility and 10 dB can result from a complete restriction that leads to a complete loss of quality of the visibility , In particular, if a stable object O _i can no longer be detected, instead of using the statistical approach with a range monitoring element, a timeout monitoring element and an object loss monitoring element, the RCS monitoring element DeltaRCS monitoring element ^{k is} used exclusively or in addition to the statistical approach, this determines whether there is a restriction or whether the object has simply disappeared from the FoV of the short-range scan and or the FoV of the long-range scan of the radar sensor.

All steps or a part of the steps can or can also be carried out in parallel.

In 2 is simply a computer program 20 shown that performs the method using the RCS restriction detection monitor that is shown in 1 is shown.

• In einem Erfassungsschritt 21 werden stabile Objekte O_i mit einem Radarsensor erfasst. Die Zyklen k umfassen einen Nahbereichsscan und einen Fernbereichsscan mit dem Radarsensor.

The steps of the computer program 20 are performed for each cycle k in a loop, where k runs from 1 to n:

• In one acquisition step 21 stable objects O _i are detected with a radar sensor. The cycles k include a short-range scan and a long-range scan with the radar sensor.

• - einer Zieldichte des Objekts O_i;
• - davon, ob das' Objekt O_i real ist;
• - davon, ob das Objekt O_i verdeckt ist;
• - davon, ob sich das Objekt O_i ganz in der Nähe befindet;
• - einer Lebensdauer des Objekts O_i;
• - einer Relativgeschwindigkeit des Objekts O_i und/oder
• - einem Winkel des Objekts O_i.

In an optional investigation step 21.1 a weight w _{i is determined} for each stable object O _i on the basis of at least:

• a target density of the object O _i ;
• - whether the 'object O _{i is} real;
• - whether the object O _{i is} covered;
• - whether the object O _{i is} very close;
• - a lifetime of the object O _i ;
• - a relative speed of the object O _i and / or
• - an angle of the object O _i .

In one investigative step 22 an RCS value for the short-range scan RCS _{i, near} ^k and / or an RCS value for the long-range scan RCS _{i, far} ^{k is determined} for each stable object O _i .

In one calculation step 23 a deviation value of the RCS value of the short-range scan DeltaRCS _{i, Nah} ^k and / or a deviation value of the RCS value of the short-range scan DeltaRCS _{i, Fern} ^k for each stable object (O _i ) based on a change between the respective RCS values RCS _{i , Nah} ^k , RCS _{i, Fern} ^{k of} the current cycle k and the respective RCS values RCS _{i, Nah} ^kx , RCS _{i, Fern} ^{kx of} the previous cycles kx. x is greater than or equal to 1 here.

In an optional calculation step 23.1 at least one mean, a variance, a standard deviation and / or a confidence based on the deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^{k of} the current cycle k and the deviation values DeltaRCS _{i, Nah} ^kx , DeltaRCS _{i, Fern} ^{kx of} the previous one Cycles (kx) calculated. x is greater than or equal to 1 here.

In an optional filter step 23.2 at least the mean, the variance, the standard deviation and / or the confidence are filtered.

In one calculation step 24 an RCS monitoring element DeltaRCS monitoring element ^{k of} the cycle ^{k is} calculated based on the deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k . The calculation of the RCS monitoring element DeltaRCS monitoring element ^k can also be based on the weights w _i . The calculation of the RCS monitoring element DeltaRCS monitoring element ^k can also be based on at least the (filtered) mean value, the (filtered) variance, the (filtered) standard deviation and / or the (filtered) confidence. To calculate the RCS monitoring element DeltaRCS monitoring element ^k , a histogram of the deviation values DeltaRCS _{i, Nah} ^k , DeltaRC-S _{i, Fern} ^{k can be} determined by recognizing a respective class of each stable object O _i in the FoV of the radar sensor, which is a combination of the FoV of the short-range scan and the FoV of the long-range scan.

In one step 25 based on a change in the RCS monitoring element DeltaRCS monitoring element ^{k of} the current cycle k based on the RCS monitoring element DeltaRCS monitoring element ^{kx of} the previous cycles kx, it is determined whether there is a restriction of the radar sensor, x is greater than or equal to 1 here.

All steps or a part of the steps can or can also be carried out in parallel.

In 3A and 3B simplified histograms of RCS values are shown. The RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^k are calculated in dB and a histogram with 16 classes of size 6.25 between -40 and +60 dB is generated. If no stable objects O _i are detected, as in 3A is shown, the histogram of the RCS values has a peak at 0 dB and an average 31 at 0 dB. In 3B a histogram of RCS values is shown, in which the RCS values of two stable objects are given. The peak 32 belongs to a stable object O ₁ with an RCS value RCS ₁ of 42 dB and a weight w ₁ of 50. The peak 33 belongs to a stable object O ₂ with an RCS value RCS ₂ of 29 dB and a weight w ₂ of 40. The mean 31 is through the two peaks 32 . 33 shifted to the right.

In 4A and 4B simplified histograms of deviation values are shown. The deviation values DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k are calculated in dB and a histogram with 16 classes of size 6.25 between -40 and +60 dB is generated. If the RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^{k of} the stable objects O _i have no change, the histogram has a peak and mean 41 at 0 dB as in 4A is shown. If the RCS values RCS _{i, Nah} ^k , RCS _{i, Fern} ^{k of} the stable objects O _i change, the peak and the mean value shift 41 of the histogram to the left (here around -5 dB). If the mean 41 of the histogram is approximately 0 dB, a restriction-related loss of a stable object O _{i is} unlikely and, if the mean is shifted to the left, such a restriction-related loss is more likely. Based on this probability of a restriction of the radar sensor, the RCS monitoring element DeltaRCS monitoring element ^k can be determined and a decision is made as to whether there is a restriction.

In 5 is a simplified system 50 shown using the RCS restriction detection monitor. The system 50 comprises at least one radar sensor 51 and is set up to perform the steps of the method as described above for the at least one radar sensor 51 performs.

In 6 is simply an autonomous vehicle 60 shown that the system 50 using the RCS restriction detection monitor included in 5 is shown. The autonomous vehicle 60 comprises at least one radar sensor 51 and at least one system 50 , A control unit of the autonomous vehicle 60 can from the system 50 about restrictions of the at least one radar sensor 51 Use the information provided for the autonomous vehicle 60 to control or drive autonomously.

While specific embodiments have been illustrated and described in the present document, those of ordinary skill in the art will recognize that there are various alternative and / or equivalent implementations. It should be recognized that the exemplary embodiment or exemplary embodiments are only examples and are in no way intended to limit the scope, applicability or design. Rather, the foregoing brief description and the detailed description provide the person skilled in the art with an expedient overview for implementing at least one exemplary embodiment, it being understood that various changes can be made to the function and arrangement of elements that are described in one exemplary embodiment, without the need for the in the attached claims and their legal counterparts set out. This application is generally intended to cover any adaptations or changes to the embodiments discussed herein.

In the foregoing detailed description, various features are summarized in one or more examples or examples to rationalize the disclosure. It is to be understood that the foregoing description is intended to be illustrative and not restrictive. It is intended to cover all alternatives, modifications and equivalents which may possibly be included in the scope of the invention. Many other examples will be apparent to those skilled in the art from the foregoing description.

The terminology used in the foregoing description is used to better understand the invention. However, it will be apparent to a person skilled in the art in view of the description set forth in the present document that the specific details for the application of the invention are not necessary. The foregoing descriptions of specific embodiments of the present invention have thus been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously many modifications and variations are possible in view of the above teachings. The embodiments have been selected and described in order to best explain the principles of the invention and its practical applications, thereby enabling other persons skilled in the art to make the best possible use of the invention and the various embodiments with various modifications that are suitable for the specific use under consideration. Throughout the description, the terms “have” and “in” are used as the generally understandable counterparts of the corresponding terms “comprise” and “where”, respectively. In addition, the terms "first", "second (r)" and "third" etc. are only used as names and should not impose any numerical requirements on their objects or a specific listing create the objects by meaning. In the context of the present description and claims, the conjunction "or" is to be understood as including ("and / or") and not excluding ("either ... or").

LIST OF REFERENCE NUMBERS

10

Method using an RCS limiter detection monitor

11

Step for detecting stable objects O _i

11.1

optional step for determining a weight w _i

12

Step for determining an RCS value RCS _{i, Nah} ^k , RCS _{i, Fern} ^k

13

Step for calculating the deviation value DeltaRC-S _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k

13.1

optional step to calculate a mean, a variance, a standard deviation and / or a confidence

13.2

optional step to filter the mean, variance, standard deviation and / or confidence

14

Step for calculating an RCS monitoring element DeltaRCS monitoring element ^k

15

Step to determine if there is a restriction on the radar sensor

20

computer program 20 which performs the method using the RCS restriction detection monitor described in 1 is shown

21

Step for detecting stable objects O _i

21.1

optional step for determining a weight w _i

22

Step for determining an RCS value RCS _{i, Nah} ^k , RCS _{i, Fern} ^k

23

Step for calculating the deviation value DeltaRC-S _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k

23.1

optional step to calculate an average, a deviation, a standard deviation and / or a confidence

23.2

optional step to filter the mean, variance, standard deviation and / or confidence

24

Step for calculating an RCS monitoring element DeltaRCS monitoring element ^k

25

Step to determine if there is a restriction on the radar sensor

31

Average

32

peak

33

peak

41

Average

50

System using an RCS restriction detection monitor

51

radar sensor

60

autonomous vehicle

Claims (13)

Restriction detection method for a radar sensor using a radar cross-section (RCS) monitoring element, which comprises the steps: - Detection of stable objects (O _i ) with the radar sensor in cycles (k), the cycles (k) including a short-range scan and a long-range scan include the radar sensor; - determining an RCS value for the short-range scan (RCS _{i, near} ^k ) and / or an RCS value for the long-range scan (RCS _{i, far} ^k ) for each stable object (O _i ) for each cycle (k); - Calculate a deviation value of the RCS value of the short-range scan (DeltaRCS _{i, near} ^k ) and / or a deviation value of the RCS value of the far-range scan (DeltaRCS _{i, far} ^k ) for each stable object (O _i ) for each cycle (k) on a change between the respective RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) of the cycle (k) and the respective RCS values (RCS _{i, Nah} ^kx , RCS _{i, Fern} ^kx ) of the previous cycles ( kx), where x is greater than or equal to 1; - Calculating an RCS monitoring element (DeltaRCS monitoring element ^k ) of the cycle (k) based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) of the respective cycle (k); - Determine whether the radar sensor is restricted based on a change in the RCS monitoring element (DeltaRCS monitoring element ^k ) of the cycle (k) in relation to the RCS monitoring element (DeltaRCS monitoring element ^kx ) of the previous cycles (kx), where x is greater than or equal to 1 , Procedure according to Claim 1 , the method further comprising the step of: - determining a weight (w _i ) for each stable object (O _i ) based on at least: - a target density of the object (O _i ); - whether the object (O _i ) is real; - whether the object (O _i ) is covered; - whether the object (O _i ) is very close; - a lifetime of the object (O _i ); - a relative speed of the object (O _i ) and / or - an angle of the object (O _i ) and the calculation of the RCS monitoring element (DeltaRCS monitoring element ^k ) is also based on the weights (w _i ). Method according to one of the preceding claims, wherein the calculation of the RCS monitoring element (DeltaRCS monitoring element ^k ) comprises determining a histogram of the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) by recognizing a respective class of each stable object (O _i ) in a field of view, FoV, of the radar sensor. Method according to one of the preceding claims, the method further comprising the step of: - calculating at least one mean value, a variance, a standard deviation and / or a confidence based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ) des Cycle (k) and the deviation values (DeltaRCS _{i, Nah} ^kx , DeltaRC-S _{i, Fern} ^kx )) of the previous cycles (kx), where x is greater than or equal to 1, and wherein the calculation of the RCS monitoring element (DeltaRCS monitoring element ^k ) is based on based at least on the mean, variance, standard deviation and / or confidence. Procedure according to Claim 4 , the method further comprising the step of: - filtering at least the mean value, the variance, the standard deviation and / or the confidence, and wherein the calculation of the monitoring element (DeltaRCS monitoring element ^k ) based on at least the filtered mean value, the filtered variance, the filtered standard deviation and / or the filtered confidence. Method according to one of the preceding claims, wherein the stable objects (O _i ) are dynamic objects or static objects. Restriction detection system for a radar sensor using an RCS monitoring element, the system being set up to carry out the steps of the method according to one of the preceding claims. Computer program that follows the restriction detection method for a radar sensor using an RCS monitor Claim 1 which comprises the steps of: for each cycle (k): - detecting dynamic objects (O _i ) with the radar sensor using a short-range scan and a long-range scan with the radar sensor; - determining an RCS value for the short-range scan (RCS _{i, near} ^k ) and / or an RCS value for the long-range scan (RCS _{i, far} ^k ) for each stable object (O _i ); - Calculating a deviation value of the RCS value of the short-range scan (DeltaRCS _{i, near} ^k ) and / or a deviation value of the RCS value of the far-range scan (DeltaRCS _{i, far} ^k ) for each stable object (O _i ) based on a change between the respective ones RCS values (RCS _{i, Nah} ^k , RCS _{i, Fern} ^k ) of the current cycle (k) and the respective RCS values (RCS _{i, Nah} ^kx , RCS _{i, Fern} ^kx ) of the previous cycles (kx), where x is greater than or equal to 1; - Calculating an RCS monitoring element (DeltaRCS monitoring element ^k ) based on the deviation values (DeltaRCS _{i, Nah} ^k , DeltaRCS _{i, Fern} ^k ); - Determine whether there is a restriction of the radar sensor based on a change in the RCS monitoring element (DeltaRCS monitoring element ^k ) of the current cycle (k) in relation to the RCS monitoring element (DeltaRCS monitoring element ^kx ) of the previous cycles (kx), where x is greater than or equal to 1 is. Computer program after Claim 8 , wherein the computer program carries out the method according to one of claims 2 to 6. Vehicle following the restriction detection system for a radar sensor using an RCS monitor Claim 7 includes and further includes: one or more radar sensors, the restriction detection system being set up to detect a restriction for each radar sensor of the vehicle. Vehicle after Claim 10 , the vehicle further comprising driver assistance systems (ADAS). Vehicle after Claim 11 wherein the vehicle further includes an adaptive cruise control (ACC). Vehicle according to one of claims 10 to 12, wherein the vehicle is an autonomous vehicle.

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