Coherent distributed radar system for maneuvering and / or parking assistance

Abstract

Radar system (100) for maneuvering and / or parking assistance, comprising at least one central station (200) and a plurality of radar devices (300, 300-k, 400, 400-l) linked to the central station (200) via optical transmission links (500, 510); wherein the central station (200) is configured to generate the radar signal information to be emitted by each of the plurality of radar devices (300, 300-k, 400, 400-l) and to modulate each of these signals onto a terahertz signal in order to transmit the modulated signal via the optical transmission links (500, 510) to the respective radar devices (300, 300-k, 400, 400-l) and wherein each of the plurality of radar devices (300, 300-k, 400, 400-l) comprises an antenna and are trained to receive the radar signal information and to multiply it with respect to frequency and transmit it via the antenna (260,360) to transmit and to modulate received radar signal information onto a terahertz signal and to transmit it optically back to the central station (200), wherein the central station (200) is additionally configured to evaluate the received radar signal information from the plurality of radar devices, characterized in that the central station (200) is configured to generate and evaluate the radar signal information to be transmitted and the radar signal information received differently depending on a driving situation, wherein during a driving process at least a subset of the plurality of radar devices (300, 300-k, 400, 400-l) is used both individually for pure distance and relative speed measurement and coherently coupled with at least one further of the plurality of radar devices (300, 300-k, 400, 400-l),to detect objects in the immediate vicinity of the vehicle (1000; 2500) during maneuvering and / or parking operations and / or for collision avoidance and / or collision consequence reduction.

Description

The invention relates to the detection of the environment of vehicles, in particular motor vehicles, which is carried out by means of a radar system to support maneuvering and parking operations. In particular, the invention relates to radar systems that enable high resolution with respect to angular resolution. For driver assistance systems and automated driving, the safest possible environmental perception is essential. This involves capturing the vehicle's surroundings using sensors such as ultrasound, radar, lidar, and cameras. Ideally, a comprehensive 360° 3D environmental scan is achieved, capturing all static and dynamic objects. Lidar, in particular, has historically played a crucial role in redundant, robust environmental perception systems, as this sensor type can precisely measure distances and also be used for classification. However, these sensors are expensive and complex to design. 360° 3D environmental perception is especially problematic, as it requires either numerous smaller individual sensors, typically employing many individual light sources and detector elements, or the installation of large sensors.One example of this is the Velodyne VLP 32C system from Ouster, Inc., San Francisco, USA. Furthermore, LiDAR systems are susceptible to weather conditions such as rain, fog, or direct sunlight. Radar sensors have been established in the automotive sector for years, reliably and consistently delivering data in all weather conditions. Even poor visibility conditions such as rain, fog, snow, dust, and darkness hardly affect their detection reliability. However, their resolution has been limited so far; production radars currently in use have a resolution of approximately 2°. To meet the requirements for Levels 4 and 5 of automated driving with safe driving functions, radar sensors must deliver high-resolution, three-dimensional images in the range of 0.1° and below, with high insensitivity to interference from their surroundings. This cannot be achieved with conventional radar technology, as the resolution of such systems is too low. DE 10 2019 114 876 A1 describes a radar antenna arrangement for a vehicle, comprising at least one vehicle component, wherein the radar antenna arrangement includes several radar units configured for transmitting and / or receiving a radar beam. The radar units are arranged on a surface of the vehicle component. The radar antenna arrangement includes at least one antenna array for determining the azimuth angle of the radar beam, which comprises several of the radar units. Directly adjacent radar units are horizontally spaced apart. The radar antenna arrangement also includes at least one antenna slit for determining the elevation angle of the radar beam, which comprises several of the radar units. Directly adjacent radar units are vertically spaced apart. The at least one antenna array and the at least one antenna slit enclose an angle α of 5° to 180°. DE 10 2016 217 134 A1 describes a motor vehicle with a detection device for angle-resolved detection of the motor vehicle's surroundings using a radar method, wherein the detection device comprises at least one antenna device configured for transmitting signals and / or receiving received signals, and a central unit, wherein the central unit and / or the antenna device each have at least one coupling device by which terahertz radiation with a wavelength between 0.1 mm and 1.0 mm can be coupled into an associated dielectric waveguide of the motor vehicle in order to transmit control signals for controlling the transmission of the transmitted signals and / or the received signals or signals derived from the received signals between the central unit and the antenna device. DE 10 2021 128 147 A1 describes an antenna device for a motor vehicle for transmitting and / or receiving electromagnetic radiation, comprising at least one first antenna element designed using liquid crystal technology for transmitting and / or receiving electromagnetic radiation, and an electronic computing device designed to generate a control signal for the at least first antenna element. The invention provides that the antenna device includes at least one second antenna element designed using liquid crystal technology for transmitting and / or receiving electromagnetic radiation, wherein the first antenna element and / or the second antenna element are activated for transmitting and / or receiving depending on the control signal. Furthermore, a communication device, a radar device, and an assistance system are described. DE 10 2022 201 477 A1 discloses a radar sensor device for a motor vehicle comprising at least: - a central electronic computing unit configured to generate an electrical control signal for a transmitter of the radar sensor device; - a laser device which, depending on the electrical control signal, generates an optical transmission signal for transmission to the transmitter; - the transmitter, which is configured to transform the optical transmission signal into an electrical output signal and to transmit the electrical output signal into the vicinity of the motor vehicle; and - a receiving device for receiving an electrical receive signal corresponding to the electrical output signal and reflected in the vicinity, and for transmitting the electrical receive signal to the central electronic computing unit;wherein the electronic computing device and / or the transmitting device and / or the receiving device comprises at least one organic electronic component. German patent application DE 10 2014 223 900 A1 discloses a driver assistance system for a vehicle comprising a laser scanner with a phased laser, a sensor unit, and an evaluation unit. The phased laser is further configured to generate a controllable and directed laser beam by means of beam shaping, and the sensor unit is configured to detect the backscatter caused by the laser beam, so that the evaluation unit can generate driver assistance data from the detected backscatter. Furthermore, assistance systems for supporting parking maneuvers are known from the state of the art. To perceive the surroundings, these systems often employ ultrasound-based systems that rely on measuring the time of flight of reflected ultrasound signals. However, these systems are either unable or only partially able to determine the angle between, for example, a vehicle axis and a detected obstacle. The invention is therefore based on the technical problem of creating improved environmental perception for maneuvering and parking operations with the lowest possible computational effort and improved environmental information. The invention is based on the idea of ​​using a coherent radar system in a vehicle to assist with maneuvering and parking situations. The radar system comprises a central station and a multitude of radar units connected to the central station via optical transmission links, through which radar signals are transmitted and / or received. It is provided that, depending on the driving situation, these radar units are operated and evaluated differently. This allows for optimal information acquisition about the surroundings while simultaneously minimizing the evaluation effort.For example, if a vehicle has already been maneuvered into a parallel parking space during a parking maneuver and is approaching another parked vehicle that borders the space in the direction of travel, then, beyond a certain distance, the angle at which the radar echoes are detected becomes only of secondary importance to the radar devices installed at the rear of the vehicle. Instead, the minimum distance and relative speed to the nearest obstacle, in this case the other parked vehicle behind, are of primary interest.In another situation, for example at the beginning of the parking process, it is of interest to determine as accurately as possible the available area for the vehicle to be parked, so that the angles to the individual obstacles or obstacle areas are also of interest, so that determining the angle of the received radar echoes is also advantageous. definition An optical transmission path is a signal transmission path in which the signal is not transmitted via electrical conductors, but via optical conductors according to the laws of optics. A radar system is a system designed to transmit and / or receive a radar signal. A radar signal is an emitted electromagnetic wave in the gigahertz frequency range. Radar signal information is the information associated with a radar signal, defined by its frequency or amplitude modulation and / or its phase. This information can also be modulated onto another carrier signal, such as an optical signal. Preferred embodiments In particular, a radar system for maneuvering and / or parking assistance is provided, comprising: at least one central station and a plurality of radar devices linked to the central station via optical transmission links; wherein the central station is configured to generate the radar signal information to be emitted by each of the plurality of radar devices and to modulate each onto a terahertz signal in order to transmit the modulated signal via the optical transmission links to the respective of the plurality of radar devices, and wherein the plurality of radar devices each comprise an antenna and are configured to receive the radar signal information and to multiply it with respect to frequency and to emit it via the antenna and to modulate a received radar signal information onto a terahertz signal and to transmit it back to the central station, wherein the central station is further configuredto evaluate the received radar signal information from the multitude of radar devices, whereby the central station is designed to generate and evaluate the radar signal information to be transmitted and the radar signal information received differently depending on a driving situation. Furthermore, a method for operating a radar system to support a maneuvering or parking operation is created, which includes: generating radar signal information to be transmitted to a large number of radar devices in a central station; Modulating the radar signal information onto a terahertz signal and optically transmitting the modulated terahertz signals to the plurality of radar devices, wherein each of the plurality of radar devices converts the generated and optically transmitted radar signal information into an electronic signal and frequency-multiplies it and emits it as a radar signal via an antenna, and modulates received radar signal information contained in a reflected radar signal onto a terahertz signal and transmits it back to the central station, wherein the central station generates and evaluates the radar signal information to be emitted and the radar signal information differently depending on the driving situation. The advantage of the invention is that, depending on the current driving situation during maneuvering and / or parking, the individual radar units are optimally deployed for environmental perception, thereby reducing the computational effort and time required for information gathering. For example, when the vehicle is at a greater distance from objects and obstacles and initially the most precise possible perception of the surroundings is desired, all or a large subset of the numerous radar units are operated coherently with each other. The increased computational effort compared to operation as a purely distance and relative speed measurement with the individual radar units operating in a non-coherent manner is offset by the additional information acquired during evaluation.Very precise environmental perception is possible, which can be used, for example, to display a virtual top view or similar before a parking or maneuvering operation. However, when approaching an extensive, two-dimensional object directly, the iteration rate at which data is acquired and evaluated can be increased if the individual radar units are used only for distance and relative velocity measurements, in which case the individual radar units are no longer operated or evaluated coherently. According to the invention, a radar system thus provides that at least a subset of the multitude of radar devices is used both individually for pure distance and relative speed measurement and coherently coupled with at least one further of the multitude of radar devices to detect objects in a near field of the vehicle during a maneuvering and / or parking operation. In a corresponding method according to the invention, it is thus provided that at least a subset of the multitude of radar devices can be individually used for pure range and Relative speed measurement is used as well as coherently coupled with at least one other of the multitude of radar devices to detect objects in a near field of the vehicle during a maneuvering and / or parking operation. One and the same radar device can therefore be used differently in the radar system or in the procedure during a parking and / or maneuvering operation. The individual radar units are preferably designed as transmitting and receiving units. This means that they can be used both for transmitting a radar signal and for detecting reflected radar signals. A radar unit designed for transmitting a radar signal, and thus configured as a transmitter, is provided that it can receive an optical terahertz signal onto which the radar signal information to be transmitted is modulated, and that the received radar signal information, which preferably has only one-eighth the frequency of the radar signal to be transmitted, is multiplied in an electrical circuit with respect to frequency, in particular, for example, by multiplying the frequency eightfold, and then transmitted as an electromagnetic radar signal.Accordingly, a radar device configured as a receiver is capable of detecting an electromagnetic radar signal echo and extracting the received radar signal information contained therein by means of baseband signal processing. This information is then modulated onto an optical signal in order to transmit the received radar signal information to a central processing unit. Preferably, this entire functionality of the radar device is implemented in a photonic electronic integrated circuit (EPIC). The photonic components are implemented in silicon-on-insulator regions, and the electronic components in so-called bulk silicon regions. Preferably, the radar system is designed such that the central station can determine at least one field of view for an upcoming driving maneuver, or can acquire data defining this field of view, and coherently operate and evaluate precisely those of the multiple radar units that cover this field of view. Depending on the driving situation, at least one field of view is thus determined for which coherently operating a portion of the multiple radar units is advantageous in order to acquire the most detailed information possible about the field of view. It is understood that several separate fields of view can exist simultaneously, for which different subsets of the radar units are coherently operated and evaluated.Simultaneously or sequentially, the same or other radar systems can also be operated and used solely for determining distance and relative velocity. If some or all of the numerous radar systems are operated coherently, a so-called MIMO evaluation is preferably employed. MIMO stands for Multiple Input Multiple Output and means that several of the radar systems are used as transmitters and several as receivers to receive these multiple transmitted radar signals. Due to the coherence, these receivers operate in phase with each other. The individual transmitters emit differently modulated signals. This allows for more precise evaluations, particularly regarding angular resolution, than with the operation of individual or adjacent radar systems.Depending on the desired angular resolution, the number of radar units operating coherently can be varied. This enables an evaluation that is dependent on the driving situation. One embodiment provides that the central station determines at least one field of view for an upcoming driving maneuver or records information defining the at least one field of view and generates coherently coupled radar signals to be emitted precisely for those of the plurality of radar devices and jointly and coherently evaluates received radar signal information that emit radar signals into this field of view and / or receive radar echoes from the field of view. In one embodiment, it is provided that the central station generates the radar signal information to be transmitted during a maneuvering and / or parking situation and evaluates the received radar signal information in such a way that the pure distance and relative speed measurements and the angle-resolved coherent environment detection are carried out individually in temporal sequence for at least a subset of the multitude of radar devices. The radar signal information is preferably generated in such a way that it comprises a frequency-modulated continuous wave signal. The invention is explained in more detail below with reference to a drawing. Here, Fig. 1 shows a schematic representation of a photonic radar system; Fig. 2a shows a front view of a vehicle; Fig. 2b shows a side view of a vehicle; Fig. 2c shows a rear view of a vehicle; Fig. 3 shows a schematic view of a vehicle parking in a parallel parking space; and Fig. 4 shows another driving situation during the parking of the vehicle in the parallel parking space according to Fig. 3. Figure 1 schematically depicts a photonic radar system 100. This system comprises a central station 200 and a plurality of radar units 300, 300-k configured as transmitters, and radar units 400, 400-l configured as receivers. The central station 200 and the transmitter radar units 300, 300-k are each individually connected to the central station via an optical fiber 500, 500-m. Similarly, the receiver radar units 400, 400-l are each individually coupled via two optical fibers 500, 500-m, 510, 510-k, one of which transmits the signal from the central station to the receiver radar unit 400, 400-l, and the other serves as a return path 510, 510-o. Lowercase letters -k, -l, -m, ... are used to represent natural numbers, to indicate that the corresponding objects are countable and distinguishable. In the illustrated embodiment, the central station 200 is configured to generate radar signal information for transmission, whereby, in the illustrated example, this occurs at a frequency eight times lower than the radar signal emitted by the corresponding radar transmitters 300. For this purpose, the central station 200 comprises a control unit 210, which controls the radar signal information generation unit 220. This unit generates a signal by adding a carrier frequency to a frequency that forms a frequency ramp over time and dividing the result by a factor of eight. This radar signal information for transmission is modulated onto an optical signal generated by a laser 230 in a modulator, which is, for example, a Mach-Zehnder modulator (MZM) 240.The optical signal is selectively switched to one of the fiber outputs 255, 255-m via a 1:N switch 250, which is controlled by a control device 210. Fiber output 255 is coupled to one of the optical waveguides, i.e., one of the 500 or 500-m fibers. The other end of the 500 or 500-m optical fibers is connected to one of the 300 or 400 radar units. A radar device 300, 300-k, configured as a transmitter, has a fiber input 305 to which the fiber 500-m coming from the central station is connected. The optical carrier signal with the superimposed and the radar signal information to be transmitted is coupled via a photoreceiver 310 into an electronic photonic integrated circuit (EPIC) 315. The photonic components are located in a region where silicon is on an insulator, whereas the electronic components are on bulk silicon. The coupled optical signal is fed to a photodiode 320 and converted into an electronic signal, which is then amplified by a transimpedance amplifier 330. Subsequently, frequency multiplication takes place in a frequency multiplier 340, in the example shown by a factor of 4.An amplifier 350 generates the required transmission power for the radar signal to be emitted, which is then emitted via an antenna 360 (TX antenna). The radar signal reflected from an object in the vicinity (not shown) is received by a radar unit 400, 400-l configured as a receiver at its antenna 460 (Rx antenna). This radar unit is also configured as an electronically photonic integrated circuit (EPIC) 415. Analogous to the radar unit 300 configured as a transmitter, the radar unit 400 configured as a receiver comprises a fiber input 405, a photoreceiver coupler 410, a photodiode 420, a transimpedance amplifier (TIA) 430, and a frequency quadrupler (x4) 440 to provide a signal for a quadrature mixer (IQ) with the necessary frequency to convert the radar signal received by the antenna 460 into a baseband signal, i.e., to extract the received radar signal information from the detected radar signal.A baseband signal processing unit (BB signal processing) 470 modulates the acquired radar signal information via a driver 475 and an optical modulator 480 onto the optical signal originally from the central station, which was coupled to the photoreceiver coupler 410. A bias setting 477 also acts on the modulator. The modulated optical signal is transmitted via an optical transmit coupler 480 to a fiber output 495, to which an optical waveguide 510-0 is connected. This waveguide modulates the acquired radar signal information onto the optical carrier signal and transports it back to the central station 200. The fiber inputs 260, 260-o for the fibers 510-o coming from the radar devices 400, 400-l designed as receivers are each coupled to a photodiode 265, a transimpedance amplifier 270 and a quadrature mixer 280 in order to transfer the corresponding acquired radar signal information to an analog-to-digital converter and a processor (ADC+PC) 290 coupled thereto, which performs the entire evaluation of the acquired radar signals. Since the signal transmission occurs via the optical carrier, the individual transmitted pieces of information are phase-locked to each other. This enables a coherent evaluation of the multiple radar units. In particular, a so-called MIMO radar signal evaluation can be performed, in which the radar echo signals generated by the various radar units 300, 300-k, configured as transmitters, are captured by the multiple radar units 400, 400-l, configured as receivers, and evaluated together. This evaluation is referred to as Multiple Input Multiple Output evaluation. This type of evaluation is known to those skilled in the art and will not be explained in further detail here. In the schematic embodiment shown in Fig. 1, the radar units 300, 300-k and 400, 400-l, configured as receivers, are shown as separate units. In other embodiments, the individual radar units can be configured as both transmitters and receivers. The corresponding components can then be implemented in an electronically photonic integrated circuit (EPIC). In order to perform environmental sensing where the angle to objects is measured both in the azimuthal angle range (i.e., an angle measured in a plane parallel to the horizontal) and in the elevation range (measured in a plane perpendicular to the horizontal), it is necessary that the radar units are not all spaced apart from each other along a single spatial direction. Preferably, the radar units are arranged along two spatial directions that intersect at an angle other than 0° and 180° or are skew to each other. Figures 2a to 2c show a schematic representation of a vehicle 1000 from its front 1002 (Fig. 2a), its left side 1004 (Fig. 2b), and its rear 1006 (Fig. 2c). Small, schematic antenna symbols 1100 are depicted, indicating the positions of radar devices. At the front 1002 of the vehicle 1000, these are arranged, for example, at intervals along a lower edge 1012 of a windshield 1010 and, viewed from the front, along a left side edge 1014 of the windshield, essentially vertically spaced apart. Additionally, radar devices 1100 are also arranged horizontally spaced apart along a front bumper 1020. On the left side 1004 of the vehicle 1000, shown in Fig. 2b, radar devices 1100 are arranged horizontally spaced apart from each other along a sill 1050, and radar devices 1100 are also arranged horizontally spaced apart from each other along a roof edge 1030. In addition, radar devices are arranged substantially vertically spaced apart from each other along a B-pillar 1040. On the rear side 1006, shown in Fig. 2c, the radar devices 1100 are arranged horizontally spaced apart from each other along the rear bumper 1070 and horizontally and vertically spaced apart from each other along a lower side edge 1064 of the rear window 1060, along the left side edge 1064 of the rear window 1060 as seen from the rear. The right side of the vehicle is not shown here, but is preferably designed analogously to the left side. Due to the arrangement of the individual radar units, it is possible to detect the entire surroundings of the vehicle 1000. The individual radar units 1100 are all individually coupled to a central unit (not shown), which supplies the radar units 1100 with the radar signal information to be transmitted and feeds the radar signal information captured in the radar echo back to the central unit. The central unit performs the evaluation. This arrangement makes it possible to perform virtually 360° environmental detection.In this way, object positions can be determined not only with respect to the azimuthal angle relative to the vehicle 1000, but also with respect to the elevation angle, which is important, for example, for clearance heights or for the height of curbs, for example in relation to opening doors, or for a ceiling height in parking garages, for example in relation to opening a tailgate. Since the computational effort for evaluating all radar devices 1100, i.e. the multitude of radar devices 1100, is very high, such a complete coherent evaluation of all radar devices 1100 together is not necessary or useful in every driving situation. Figure 3 shows a road 2000 with a parking lane 2100. A parking space 2200 is located between a front vehicle 2300 and a rear vehicle 2400, into which a parking vehicle 2500 is maneuvering. In the driving situation depicted in Figure 3 during the parking maneuver, the various radar signal beams 2600 of the multiple radar devices mounted on the vehicle are schematically indicated. Radar beams with the same hatching are operated coherently with respect to each other. This means that the central station generates the individual radar signal information to be transmitted, from which the radar signals are produced, in phase with respect to each other, and the radar signal information received via radar echoes is transmitted back to the central station in phase with respect to each other, so that MIMO radar evaluation is possible and is carried out for the corresponding radar devices.For the sake of simplicity, the radar signal beams of radar installations spaced apart from each other along a vertical line are not shown. While all radar units operate coherently in the driving situation shown in Fig. 3, the individual radar units are operated differently in another driving situation shown in Fig. 4 of the same parking maneuver. The radar units located in the rear area of ​​the parking vehicle (2500) are mostly operated individually, so that they are only evaluated for distance and relative speed measurements. Only in the rear area facing the lane are two radar units operated coherently to additionally determine the angle of potential obstacles. In the front area of ​​the vehicle, the radar units located in the right half of the vehicle and those located in the left half are each operated separately as two coherent groups to also enable angle measurement and resolution of objects. Figures 3 and 4 thus show that, depending on the specific driving situation, the individual radar units within the multitude of radar units are operated differently. For this purpose, the control unit determines the field of view of interest and accordingly uses the radar units that can cover this field of view to acquire the relevant environmental information. Information about the field of view can also be provided by an assistance system. While the positions of obstacles and their contours are of particular interest before and at the beginning of the parking maneuver, requiring angle-resolved detection, when approaching the rear vehicle, a minimum distance and relative speed are primarily of interest. Therefore, in the driving situation depicted in Figure 4, the radar units in the rear area are used individually as pure distance and relative measurement radars.Depending on the specific parking or maneuvering situation, the individual radar devices can therefore be operated differently in a temporal sequence. The environmental information can also be used, for example, to display the vehicle's surroundings in a calculated top-down view or a virtual 3D view, and to visualize this for the driver. All other uses in driver assistance systems are also possible, such as collision avoidance or supporting or enabling automated driving. The collected environmental information can thus be output to and / or made available to one or more driver assistance systems or other vehicle systems. It goes without saying that, in addition to the azimuthal angles, the elevation angles can also be determined depending on the situation, for example to monitor clearance heights or to block the opening of upward-swinging vehicle openings, such as tailgates, if the ceiling height above the vehicle is insufficient to open such a vehicle opening across its entire swing range. It will be understood by those skilled in the art that only exemplary embodiments are described here. The features described in the individual embodiments can be used in any combination to implement the invention. Reference symbol list 100 Radar system 200 Central station 210 Control unit 220 Radar signal information generation unit 230 Laser 240 Mach-Zehnder modulator (MZM) 250 1:N switch 255, 255-j Fiber outputs 260, 260-0 Fiber inputs 265 Photodiode (PD) 270 Transimpedance amplifier (TIA) 280 Quadrature mixer (IQ) 290 Analog-to-digital converter and processor (ADC+PC) 300, 300-k Radar unit (transmitter) 305 Fiber input 310 Photoreceiver coupler 315 Electronic-photonic integrated circuit (EPIC) 320 Photodiode 330 Transimpedance amplifier (TIA) 340 Frequency quadrupler (x4) 350 Amplifier (PA) 360 Antenna (Tx antenna) 400,400-l Radar unit (receiver) 405 Fiber input 410 Photoreceiver coupler 415 Electronic-photonic integrated circuit (EPIC) 420 Photodiode 430 Transimpedance amplifier (TIA) 440 Frequency quadrupler (x4) 450 Quadrature mixer (IQ) 460 Antenna (Tx antenna) 470 Baseband signal processing unit (BB signal processing) 475 Driver 477 Default setting 480 Optical modulator 490 Optical transmit coupler 495 Fiber output 500-1, ..., 500-m Optical fibers (fibers) 510-1,... 510-0 optical fibers (fibers / return channel) 1000 vehicle 1002 front 1004 left side 1006 rear 1010 windshield 1012 lower edge of windshield 1014 left side edge of windshield 1020 front bumper 1030 roof edge 1040 B-pillar 1050 sill 1060 rear window 1062 lower edge of rear window 1064 left side edge of rear window 1070 rear bumper 1100 radar equipment / antenna symbols 2000 road 2100 parking lane 2200 parking space 2300 vehicle in front 2400 vehicle behind 2500 parking vehicle 2600 radar signal beams,

Claims

Radar system (100) for maneuvering and / or parking assistance, comprising at least one central station (200) and a plurality of radar devices (300, 300-k, 400, 400-l) linked to the central station (200) via optical transmission links (500, 510); wherein the central station (200) is configured to generate the radar signal information to be emitted by each of the plurality of radar devices (300, 300-k, 400, 400-l) and to modulate each of these signals onto a terahertz signal in order to transmit the modulated signal via the optical transmission links (500, 510) to the respective radar devices (300, 300-k, 400, 400-l) and wherein each of the plurality of radar devices (300, 300-k, 400, 400-l) comprises an antenna and are trained to receive the radar signal information and to multiply it with respect to frequency and transmit it via the antenna (260,360) to transmit and to modulate received radar signal information onto a terahertz signal and to transmit it optically back to the central station (200), wherein the central station (200) is additionally configured to evaluate the received radar signal information from the plurality of radar devices, characterized in that the central station (200) is configured to generate and evaluate the radar signal information to be transmitted and the radar signal information received differently depending on a driving situation, wherein during a driving process at least a subset of the plurality of radar devices (300, 300-k, 400, 400-l) is used both individually for pure distance and relative speed measurement and coherently coupled with at least one further of the plurality of radar devices (300, 300-k, 400, 400-l),to detect objects in the immediate vicinity of the vehicle (1000; 2500) during maneuvering and / or parking operations and / or for collision avoidance and / or collision consequence reduction. Radar system (100) according to claim 1, characterized in that the central station (200) is configured to determine at least one field of view for an upcoming driving maneuver or to acquire information defining the at least one field of view and to operate and evaluate exactly those of the plurality of radar devices (300, 300-k, 400, 400-l) in a coherently coupled manner that cover this field of view. Radar system (100) according to one of the preceding claims, characterized in that the central station (200) generates the radar signal information to be emitted and evaluates the received radar signal information during a maneuvering and / or parking operation and / or for collision avoidance and / or for collision consequence reduction in such a way that for at least a subset of the plurality of radar devices (300, 300-k, 400, 400-l) the pure distance and relative speed measurements and the angle-resolved coherent environment detection and / or vice versa are carried out individually in temporal sequence. Radar system (100) according to one of the preceding claims, characterized in that the radar signal information to be emitted comprises a frequency-modulated continuous wave signal. Method for operating a radar system (100) for assisting a maneuvering or parking operation, comprising: generating radar signal information to be transmitted to a plurality of radar devices (300, 300-k, 400, 400-l) in a central station (200); modulating the radar signal information each onto a terahertz signal and optically transmitting the modulated terahertz signals to the plurality of radar devices, wherein each of the plurality of radar devices (300, 300-k, 400, 400-l) converts the generated and optically transmitted radar signal information into an electronic signal and frequency-multiplies it and transmits it as a radar signal via an antenna (260, 360) and / or modulates received radar signal information contained in a reflected radar signal onto a terahertz signal and transmits it back to the central station (200), characterized in thatthat the central station (200) generates and evaluates the radar signal information to be transmitted and the radar signal information received differently depending on the driving situation, wherein during a driving process at least a subset of the multitude of radar devices (300, 300-k, 400, 400-l) is used both individually for pure distance and relative speed measurement and coherently coupled with at least one further of the multitude of radar devices (300, 300-k, 400, 400-l) to detect objects in a near field of the vehicle (1000; 2500) during a maneuvering and / or parking operation and / or for collision avoidance and / or collision consequence reduction. Method according to claim 5, characterized in that the central station (200) determines at least one field of view for an upcoming driving maneuver or records information defining the at least one field of view and generates coherently coupled radar signals to be emitted precisely for those of the plurality of radar devices (300, 300-k, 400, 400-l) and coherently evaluates received radar signal information jointly which emit radar signals into this field of view and / or receive radar echoes from the field of view. Method according to one of claims 5 or 6, characterized in that the central station (200) generates the radar signal information to be transmitted and evaluates the received radar signal information during a maneuvering and / or parking operation in such a way that, for at least a subset of the plurality of radar devices (300, 300-k, 400, 400-l), the pure distance and relative speed measurements and the angle-resolved coherent environment detection and / or vice versa are carried out individually in temporal sequence. Method according to one of claims 5 to 7, characterized in that the radar signal information to be transmitted is generated in such a way that it comprises a frequency-modulated continuous wave signal.

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