Method of operating a vehicle multiple range radar system - Patents.com

Abstract

A method of operation of a radar system (12) for a vehicle (10), the radar system (12), and the vehicle (10) are described in which the radar system (12) is used to perform at least one radar measurement within which at least one radar signal is transmitted by at least one transmitting antenna element of at least one transmitting antenna arrangement of the radar system (12), reception readiness for radar echo signals possibly based on the at least one radar signal is established for at least one receiving antenna element of at least one receiving antenna arrangement of the radar system (12), and the at least one transmitting antenna element is controlled according to at least one control scheme. By the start of at least one radar measurement, a basic control scheme for the radar system (12), specific to the intended use of the radar system (12) in the vehicle (10), is set for at least one measurement mode of the radar system (12), the basic control scheme is used to adjust a basic main beam axis (42) of the at least one transmitting antenna arrangement to the intended use of the radar system (12), and the at least one radar measurement is performed based on the basic control scheme.

Description

[Technical field]

[0001] The present invention relates to a method of operation of a radar system for a vehicle, the radar system being used to perform at least one radar measurement involving using at least one transmitting antenna element of at least one transmitting antenna arrangement of the radar system for transmitting at least one radar signal and arming at least one receiving antenna element of at least one receiving antenna arrangement of the radar system for receiving any radar echo signals based on the at least one radar signal, the at least one transmitting antenna element being operated according to at least one control scheme.

[0002] The invention further relates to a radar system for a vehicle having at least one transmitting antenna arrangement with at least one transmitting antenna element for transmitting radar signals, at least one receiving antenna arrangement with at least one receiving antenna element for receiving radar return signals, and at least one control and detection device for operating the at least transmitting antenna element and for detecting radar return signals received by the at least one receiving antenna element, wherein the radar system has at least one adjusting means with at least one control scheme for adjusting at least one main beam axis of the at least one transmitting antenna arrangement.

[0003] The invention additionally relates to a vehicle comprising at least one radar system. [Background technology]

[0004] A radar system and an operating method thereof are known from DE102019134304A1. The radar system comprises a plurality of transmitting antennas, by means of which radar signals can be transmitted into a monitoring area of ​​the radar system, a plurality of receiving antennas, by means of which echoes from the radar signals reflected in the monitoring area can be received, and at least one antenna electronic unit, to which the transmitting and receiving antennas are connected for signal transfer via an antenna feed line. The radar signals can be emitted using beamforming and / or beam steering methods. Additionally or alternatively, it is possible to switch between a beamforming mode with an extended range and a conventional MIMO mode with an increased angular resolution. The radar system and the method can be used in vehicles, in particular in motor vehicles. Summary of the Invention [Problem to be solved by the invention]

[0005] The invention is based on the object of designing a radar system, a method and a vehicle of the kind mentioned in the introduction, which make it possible to expand the possibilities for using the radar system. [Means for solving the problem]

[0006] The invention achieves the object of the method in that a basic control strategy for a radar system, which is specified according to the intended use of the radar system in a vehicle, is adjusted for at least one measurement mode of the radar system at the latest at the start of at least one radar measurement, the basic control strategy being used to adapt a basic main beam axis of at least one transmitting antenna arrangement to the intended use of the radar system, and the at least one radar measurement being performed starting from the basic control strategy.

[0007] Alternatively or additionally, the invention may achieve the object of a method in that the method is suitable for operating at least one radar system according to the invention.

[0008] According to the invention, a basic control strategy is determined based on the intended use of the radar system in the vehicle. The intended use implies a mounting position and / or arrangement of the radar system on the vehicle. The basic control strategy is determined based on the intended use, so that a basic main beam axis of at least one transmitting antenna arrangement is arranged relative to at least one radar system reference area for at least one measurement mode of the radar system. In this way, one and the same radar system can be adapted to different intended uses, in particular different mounting positions and / or different arrangements on the vehicle. The adaptation only requires that the basic control strategy is changed. The adaptation can be performed using software. In this way, no changes to the hardware are required. At least one radar measurement is performed starting from the basic control strategy. Other control strategies, in particular control strategies based on MIMO and / or beamforming methods, can be "matched" to the basic control strategy, so to speak.

[0009] The basic control strategy is adapted for at least one measurement mode of the radar system, the measurement mode being a mode in which the radar system is at least temporarily operated, in particular it may be a range measurement mode, in particular a short range measurement mode or a long range measurement mode.

[0010] In the beamforming method, the transmitting antenna elements are actuated by coherent transmit control signals that define a phase shift relative to one another. The individual radar signals emitted by the individual transmitting antenna elements are superimposed to form a composite radar signal. The superposition allows the beam angle and therefore the field of view of the composite radar signal to be reduced compared to the field of view of the individual radar signals. The energies of the individual radar signals can thus be combined and the range of the composite radar signal can be expanded. The direction of the main beam axis of the composite radar signal can also be changed by appropriately changing the phase shift. The main beam axis defines the propagation direction and therefore the field of view of the composite radar signal.

[0011] In the MIMO method (multiple-in-multiple-out method), the individual radar signals of the individual transmitting antenna elements are coded differently, so that the signal paths of the individual radar signals can be evaluated by the individual transmitting antenna elements independently of each other. It is therefore possible to achieve a higher angular resolution compared to the beamforming method. No additional focusing of the transmitting power is performed here, which results in a smaller range than in the case of the beamforming method.

[0012] The principal main beam axis is the axis of at least one transmitting antenna arrangement, from which further adjustments in the direction of the principal beam axis can be made during the radar measurement. In particular, the principal main beam axis can be arranged in the case of a vehicle so that it points in the direction of travel or against the direction of travel.

[0013] The radar system may be used in vehicles, in particular motor vehicles. The radar system may advantageously be used in land vehicles, in particular cars, trucks, buses, motorcycles, etc., aircraft, in particular drones, and / or ships. The radar system may also be used in vehicles that may be operated autonomously or at least semi-autonomously.

[0014] The radar system may advantageously be connected to or be part of at least one electronic control device of the vehicle or machine, in particular a driver assistance system and / or a chassis control system and / or a driver information device and / or a parking assistance system and / or a movement recognition system, etc. In this way, at least some of the functions of the vehicle may be performed autonomously or semi-autonomously.

[0015] Radar systems may be used to detect stationary or moving objects, in particular vehicles, people, animals, vegetation, obstacles, uneven driving surfaces, in particular potholes or stones, road boundaries, road signs, open areas, in particular parking areas, precipitation, etc., and / or movement and / or motion.

[0016] In one advantageous configuration of the method, at least two transmitting antenna elements of at least one transmitting antenna arrangement can be operated using respective transmit control signals to emit respective mutually coherent individual radar signals that are superimposed to form at least one radar signal, and in a basic control scheme for the radar system, a basic phase shift between the respective transmit control signals, which may be zero, is specified for the at least two transmitting antenna elements. The phase shift between the two coherent individual radar signals can be used to change, in particular to rotate, a main beam axis of the superimposed radar signal composed of the individual radar signals. The basic phase shift can be used to adjust the basic main beam axis.

[0017] In another advantageous configuration of the method, a phase shift between the respective transmit control signals, in particular a basic phase shift, can be adjusted by at least one phase shifter and / or a phase shift linearly proportional to the distance between the at least two transmit antenna elements can be adjusted. The phase shift can be easily adjusted by a phase shifter. A phase shift linearly proportional to the distance between the at least two transmit antenna elements allows constructive superposition of the individual radar signals.

[0018] In another advantageous configuration of the method, the at least one basic control strategy can be adjusted using at least one intended use variable characterizing the intended use, the at least one intended use variable being specifiable in a control device for the radar system, in particular in a control device of the radar system, at the latest when the radar system is installed in the vehicle, and / or The at least one basic control strategy may be arranged in a controller for the radar system, in particular in a controller of the radar system, which may then be used to process the at least one basic control strategy further using software.

[0019] The basic control strategy may advantageously be stored in a storage medium of the control device, so that the basic control strategy can be easily made available to the control device.

[0020] In a further advantageous configuration of the method, The basic control scheme may be used to adapt the basic main beam axis for intended use in the long range measurement mode of the radar system; and / or the radar system can be operated in different distance measuring modes, in particular a long distance measuring mode and a short distance measuring mode, alternately or at least partially overlapping in time; and / or At least one of the transmitting antenna elements may be operated in a number of different distance measurement modes to transmit radar signals and / or a number of receiving antenna elements of at least one receiving antenna arrangement may be armed to receive echo signals.

[0021] In the long-range measurement mode, it is particularly advantageous to determine the direction of the principal main beam axis, since in this measurement mode the transmitted radar signals are combined at smaller beam angles, thus increasing the range.

[0022] Radar systems can be operated in different ranging modes, in particular a long-range measuring mode and a short-range measuring mode.

[0023] In the short-range measurement mode, it is possible to detect objects close to the radar system, in particular at distances of up to 100 m, in particular up to approximately 80 m. This requires a narrower range of radar signals than in the long-range measurement mode. The transmission energy can therefore be distributed over a suitably sized beam angle. In this way, a suitably sized field of view can be created in the short-range measurement mode.

[0024] In the long-range measurement mode, objects can be detected at greater distances, especially in the region of up to 200 m or more. This requires that the energy of the radar signal be combined to create an adequate range. Hence, the beam angle, and therefore the field of view, is smaller in the long-range measurement mode than in the short-range measurement mode.

[0025] The different distance measuring modes can be created successively or partly simultaneously. In this way it is possible to detect both objects close to the radar system in a correspondingly wide field of view and objects at greater distances in a correspondingly narrow field of view. Objects located in front of the vehicle in the direction of travel or behind the vehicle in the direction of travel can therefore be identified at an early stage in the long-distance measuring modes.

[0026] At least some of the transmitting antenna elements may be operated in a number of different distance measurement modes to transmit radar signals. In particular, some transmitting antenna elements may be used both in a long-range measurement mode and in a short-range measurement mode. In this way, the number of transmitting antenna elements required may be reduced.

[0027] Multiple receive antenna elements of at least one receive antenna arrangement may be armed to receive. The use of multiple receive antenna elements allows for improved determination of the direction of a detected object.

[0028] In a further advantageous configuration of the method, the radar system may be operated at least temporarily using a control scheme based on a beamforming technique and / or at least temporarily using a control scheme based on a MIMO technique; and / or At least one transmit antenna arrangement can be at least temporarily activated in at least two transmit antenna groups, and the transmit antenna elements within one transmit antenna group can be activated together and the transmit antenna groups can be activated individually.

[0029] Beamforming methods can be used to adjust, in particular redirect, the transmitted radar signal, and MIMO methods can be used to distinguish the radar signals of different transmitting antenna elements at the receiving end.

[0030] The transmitting antenna elements in a transmitting antenna group can be activated more easily, in particular together. The coordinated activation of two transmitting antenna elements can be used to superimpose the individual radar signals emitted thereby to form a composite radar signal. The transmission energy and range of the composite radar signal can therefore be increased.

[0031] The individual activation of the transmitting antennas allows the respective radar signals to be coded, so that it is possible to distinguish the radar signals and signal paths of the transmitting antennas at the receiving side, thus improving the determination of the direction of the detected object.

[0032] In a further advantageous configuration of the method, At least one respective corresponding base control strategy may be specified for use of the radar system as a front radar system, a corner radar system, a side radar system, and / or a rear radar system; and / or The basic control method can be used to align a basic main beam axis of at least one transmitting antenna arrangement with respect to at least one vehicle reference field, in particular with respect to the vehicle longitudinal axis, and / or The basic control schemes can be used to align the basic main beam axis of at least one transmitting antenna arrangement with respect to at least one radar system reference region, in particular the antenna plane. In this way, the basic main beam axis can be adjusted in each case according to the respective basic control scheme so that it points in the direction of travel or against the direction of travel of the vehicle, regardless of the intended use of the radar system as a front radar system, a corner radar system, a side radar system or a rear radar system. Thus, in the basic setting of the radar system depending on the intended use, it is possible to detect objects in front of or behind the vehicle in the direction of travel.

[0033] The basic control method can advantageously be used to align the basic main beam axis with respect to at least one vehicle reference field, in particular with respect to the vehicle longitudinal axis. In this way, the radar system can always be adjusted according to the intended use, so that it can be aligned in the intended surveillance field, in particular in front of the vehicle in the direction of travel or behind the vehicle in the direction of travel, regardless of its own orientation and / or its mounting position on the vehicle.

[0034] Alternatively or additionally, the basic control scheme may be used to align the basic main beam axis with respect to at least one radar system reference region. In this manner, the basic control scheme may be specified before the radar system is mounted on a vehicle, in particular during manufacturing of the radar system.

[0035] The reference range of the at least one radar system may be an imaginary axis and / or plane related to the geometry of the radar system, in particular the antenna arrangement, and may advantageously be an antenna plane in which the respective phase centers of at least some of the transmitting and / or receiving antenna elements are located.

[0036] In another advantageous configuration of the method, the at least one radar measurement may involve ascertaining at least one direction variable characterizing at least one direction of the at least one object reflecting the at least one transmitted radar signal to the radar system in at least one dimension and / or ascertaining at least one distance variable characterizing at least one distance of the at least one object reflecting the at least one transmitted radar signal to the radar system and / or ascertaining at least one speed variable characterizing at least one speed of the at least one object reflecting the at least one transmitted radar signal to the radar system. In this way, it is possible to determine object information in the form of a direction and / or a distance and / or a speed of the object relative to the radar system, i.e. also relative to the vehicle. The object information thus obtained may be transmitted to a driver assistance system of the vehicle. The driver assistance system may be used to control driving functions of the vehicle based on the object information.

[0037] In another advantageous configuration of the method, a number of transmitting antenna elements of the antenna arrangement can be activated to transmit radar signals and a number of receiving antenna elements of the antenna arrangement can be put on standby to receive echo signals, and a geometric folding of the geometric positions of the transmitting and receiving antenna elements of the antenna arrangement is used to determine a corresponding virtual receiving antenna array. In this way, it is possible to implement a virtual receiving antenna array having more virtual receiving antenna elements than the real antenna arrangement. In that way, the performance of the radar system can be improved. A suitable geometric arrangement of the transmitting and receiving antenna elements allows the corresponding virtual receiving antenna array to be adjusted. In that way, the angular resolution, in particular for direction determination, can be improved.

[0038] Furthermore, the present invention achieves the object of the radar system in that the at least one adjusting means has at least two basic control schemes for different adjustment of the at least one main beam axis in at least one measurement mode of the radar system, and at least one intended use determining means for determining one of the at least two basic control schemes based on an intended use of the radar system in at least one measurement mode of the radar system.

[0039] Alternatively or additionally, the invention may achieve the object of a radar system, in that the radar system comprises means for carrying out the method according to the invention.

[0040] According to the invention, the radar system has at least one adjustment means that can be used to adjust at least two basic control strategies based on the intended use of the radar system. In this way, the same radar system can be adjusted for at least two intended uses that require different adjustments of at least one main beam axis. At least one intended use identification means can be used to identify an appropriate basic control strategy that matches the desired intended use.

[0041] In another advantageous embodiment, the at least one adjustment means and / or the at least two basic control strategies and / or the at least one intended use determination means may be implemented at least partly using software, in particular in the control and detection device, in this way one and the same radar system may be adapted to different intended uses, in particular for different mounting positions and / or different arrangements in the vehicle, without changing the hardware.

[0042] In another advantageous embodiment, the at least one adjustment means may have a basic control scheme for use of the radar system as a front radar system and / or at least one basic control scheme for use of the radar system as a corner radar system and / or at least one basic control scheme for use of the radar system as a side radar system and / or a basic control scheme for use of the radar system as a rear radar system. In this way, the radar system can be easily adapted to the applicable intended use.

[0043] The principal main beam axis can therefore advantageously be aligned parallel to the longitudinal axis of the vehicle, regardless of the mounting position and alignment of the radar system on the vehicle, so that it is possible to use the radar system, particularly in the long-range measurement mode, to monitor a monitoring area in front of the vehicle in the direction of travel and behind the vehicle in the direction of travel.

[0044] In another advantageous embodiment, at least one transmitting antenna arrangement may have at least two transmitting antenna elements, at least two of which may be individually activated to transmit radar signals and / or at least two of the transmitting antenna elements may be activated together to transmit radar signals.

[0045] The independent activation of at least two transmit antenna elements enables the radar system to be operated according to MIMO techniques.

[0046] Alternatively or additionally, at least two transmitting antenna elements may be operated together. In this way, each individual radar signal emitted by the transmitting antenna elements may be superimposed to form a composite radar signal. The superimposition allows the transmission energy, and therefore the range of the radar signal, to be expanded. Furthermore, changing the phase shift of the individual radar signals allows the direction of the main beam to be changed.

[0047] In another advantageous embodiment, at least one transmitting antenna arrangement may have at least two transmitting antenna elements, at least two of which are arranged in a transmitting antenna group, the distance between the phase centers of adjacent transmitting antenna elements of the same transmitting antenna group corresponds to approximately half the wavelength of the emitted radar signal, and the transmitting antenna elements of the same transmitting antenna group may be activated together or individually to transmit the radar signal. The arrangement of the transmitting antenna elements in the transmitting antenna group allows the activation of the transmitting antenna elements to be simplified.

[0048] A phase centre distance of the transmitting antenna elements of the same transmitting antenna group of half the wavelength of the radar signal allows a beamforming method to be implemented in which the transmitting antenna elements of the same transmitting antenna group can be activated together.

[0049] Individually activating the transmit antenna elements allows MIMO techniques to be implemented.

[0050] In another advantageous embodiment, the at least three transmit antenna elements may be arranged in at least two transmit antenna groups, with the distance between the phase centers of adjacent transmit antenna groups being greater than half the wavelength of the transmitted radar signal and / or the distance between the phase centers of adjacent transmit antenna groups being approximately an integer multiple of half the wavelength of the transmitted radar signal. In this manner, it is possible to operate the radar system using both beamforming and MIMO techniques. Furthermore, the radar system may also be operated using a combination of beamforming and MIMO techniques.

[0051] In another advantageous embodiment, at least one transmitting antenna arrangement may be implemented as a phased array and / or the radar system may have at least one phase shifter for creating a phase shift between coherent transmit control signals for activating the transmitting antenna elements. In a phased array, the transmitting antenna elements may be activated together using coherent transmit control signals. In this case, it is possible to create a phase shift between the transmit control signals for the transmitting antenna elements. A phase shifter may be easily used to create a phase shift between the transmit control signals of the transmitting antenna elements.

[0052] In another advantageous embodiment, the at least one intended use determination means may comprise at least one intended use variable, in particular a variable characterizing the phase shift, which may be used to adjust an applicable basic control strategy which may be used to activate the corresponding transmitting antenna element.

[0053] The at least one intended use variable may advantageously be stored in suitable storage means, in particular in the storage means of the control and detection device, so that the applicable at least one intended use variable can be easily and quickly accessed.

[0054] In another advantageous embodiment, the radar system may have at least one adjustment means with at least two range control schemes to generate different distance measurement modes, in particular to create a long-range measurement mode and / or a short-range measurement mode. In this way, the radar system can be brought into a suitable distance measurement mode starting from a basic control scheme that is part of the intended use by means of a range control scheme using the at least one adjustment means. The range control scheme is, so to speak, harmonized to the applicable basic control scheme. The at least two range control schemes allow the radar system to be operated in at least two distance measurement modes, in particular in a long-range measurement mode and a short-range measurement mode.

[0055] In another advantageous embodiment, the radar system may comprise at least one means for operating the radar system using MIMO techniques, beamforming techniques and / or combined MIMO / beamforming techniques, such that the radar system may be operated using an appropriate method, in particular based on the vehicle's operating conditions, in particular based on the vehicle's driving conditions.

[0056] The MIMO, beamforming and combined MIMO / beamforming techniques may be implemented by suitable activation, in particular in groups, of the transmit antenna elements according to applicable control schemes.

[0057] At least one of the means for operating the radar system using MIMO, beamforming, and combined MIMO / beamforming techniques may be implemented using software, such that no hardware adaptation is required when changing the method.

[0058] In another advantageous embodiment, the at least one receive antenna arrangement may have at least three receive antenna elements, each with their respective phase centers located on one of two parallel imaginary receive antenna axes, with at least one phase center of the receive antenna elements located on each receive antenna axis; and / or At least one receive antenna arrangement may have at least four receive antenna elements, each with their respective phase center located on one of three parallel aerial receive antennas, with at least one phase center of the receive antenna elements located on each receive antenna axis. In this way, it is possible to ascertain the direction in which a detected object is located relative to the radar system in two dimensions, in particular in azimuth and elevation. The arrangement of the receive antenna elements on three parallel axes allows pure resolution in a direction perpendicular to the receive antenna axis and the ability to separate two objects detected using the radar system.

[0059] In another advantageous embodiment, the distance between adjacent imaginary receive antenna axes may correspond to approximately the wavelength of the radar signal transmitted by the transmit antenna elements; and / or A distance in the direction of the receive antenna axis between respective phase centers of two adjacent receive antenna elements on different receive antenna axes may correspond to approximately half the wavelength of the radar signal transmitted by the transmit antenna element; and / or A distance in the direction of the receive antenna axis between respective phase centers of two adjacent receive antenna elements on different receive antenna axes may correspond to approximately a wavelength of a radar signal transmitted by a transmit antenna element; and / or The distance between the phase centers of two adjacent receiving antenna elements on the same receiving antenna axis may correspond to an integer multiple of half the wavelength of the radar signal transmitted by the transmitting antenna element, in particular two or three times half the wavelength. In this way, the radar system may be operated according to the MIMO method, according to the beamforming method and according to a combination of the beamforming method and the MIMO method. A suitable specification of the geometrical positions of the receiving antenna elements and the geometrical positions of the transmitting antenna elements allows a virtual receiving antenna array to be generated by geometric folding. The virtual receiving antenna array may have more virtual receiving antenna elements than physically present receiving antenna elements. In this way, it is possible to improve the performance of the radar system.

[0060] In another advantageous embodiment, The phase centers of the at least two receive antenna elements may be on a first receive antenna axis, and a normal to the first receive antenna axis passing through the phase center of the at least one receive antenna element may be on an adjacent second receive antenna axis outside a region encompassing the at least two receive antenna elements on the first receive antenna axis; and / or The phase centers of the at least two receive antenna elements may be on a first receive antenna axis, a normal to the first receive antenna axis passing through the phase center of the at least one receive antenna element may be on an adjacent second receive antenna axis outside a region on the first receive antenna axis that includes the at least two receive antenna elements, and a normal to the first receive antenna axis passing through the phase center of the at least one receive antenna element may be on a third receive antenna axis outside a region on the first receive antenna axis that includes the receive antenna elements, the third receive antenna axis being located opposite the second receive antenna axis with respect to the first receive antenna axis; and / or The phase centers of the at least two receive antenna elements may be on a first receive antenna axis, the phase center of the at least one receive antenna element may be on a second receive antenna axis, and the phase center of the at least one receive antenna element may be on a third receive antenna axis, the first receive antenna axis, the second receive antenna axis, and the third receive antenna axis extending in parallel, and the at least one receive antenna element on the second receive antenna axis and the at least one receive antenna element on the third receive antenna axis are diagonally opposite to the at least two receive antenna elements on the first receive antenna axis. In this way, the performance of the radar system in beamforming, MIMO, and a combination of beamforming and MIMO methods can be further improved.

[0061] The present invention also achieves the object of a vehicle in that the vehicle has at least one radar system according to the present invention and / or the vehicle has at least one radar system having means for carrying out the method according to the present invention.

[0062] According to the invention, the vehicle comprises at least one radar system which can be used to monitor a surveillance area, in particular outside the vehicle, for objects.

[0063] Advantageously, the vehicle may have at least one driver assistance system, which may be used to operate the vehicle autonomously or semi-autonomously.

[0064] The at least one radar system may advantageously be functionally connected to at least one driver assistance system, such that information about the monitored area, in particular object information determined using the at least one radar system, may be used by the at least one driver assistance system to control the autonomous or semi-autonomous operation of the vehicle.

[0065] In other respects, the features and advantages indicated in connection with the method according to the invention, the radar system according to the invention and the vehicle according to the invention, as well as their respective advantageous configurations, apply in a mutually corresponding manner and vice versa. The individual features and advantages can essentially be combined with one another, in which case other advantageous effects may result that exceed the sum of the individual effects.

[0066] Further advantages, features and details of the present invention will become apparent from the following description, in which exemplary embodiments of the present invention are described in more detail with reference to the drawings. Those skilled in the art will also conveniently consider the features disclosed in combination in the drawings, the specification and the claims individually and combine them to form further meaningful combinations. The drawings are schematic. [Brief description of the drawings]

[0067] [Figure 1] FIG. 1 is a plan view of a vehicle with a driver assistance system and three radar systems in a driving situation. [Diagram 2] FIG. 2 is a side view of the vehicle of FIG. [Diagram 3] FIG. 2 is a detailed plan view of the vehicle of FIG. 1 in the region of the radar system. [Figure 4] FIG. 2 is a diagram illustrating the functionality of one of the radar systems of the vehicle of FIG. 1. [Diagram 5] FIG. 2 is a diagram showing the arrangement of phase centers of an antenna arrangement having a transmitting antenna element and a receiving antenna element according to a first exemplary embodiment of one of the vehicle radar systems of FIG. 1 during operation in a short-range measurement mode, with the phase center of the transmitting antenna element shown alongside the phase center of the receiving antenna element. [Figure 6] FIG. 6 shows the arrangement of phase centers for the antenna arrangement of FIG. 5 and the arrangement of virtual phase centers for the corresponding virtual antenna array. [Figure 7] FIG. 7 shows two-dimensional antenna radiation patterns for the virtual antenna array of FIG. [Figure 8] FIG. 8 shows a horizontal pattern corresponding to the antenna radiation pattern of FIG. [Figure 9] FIG. 8 shows the vertical pattern corresponding to the antenna radiation pattern of FIG. [Figure 10] FIG. 6 illustrates an arrangement of phase centers of the antenna arrangement according to the first exemplary embodiment of FIG. 5 during operation in a long range measurement mode. [Figure 11] FIG. 11 shows the arrangement of phase centers of the antenna arrangement of FIG. 10 and the arrangement of virtual phase centers of the corresponding virtual antenna array. [Figure 12] FIG. 12 shows two-dimensional antenna radiation patterns for the virtual antenna array of FIG. [Figure 13] FIG. 13 shows a horizontal pattern corresponding to the antenna radiation pattern of FIG. 12. [Figure 14] FIG. 13 shows the vertical pattern corresponding to the antenna radiation pattern of FIG. 12. [Figure 15] FIG. 2 is a diagram showing the arrangement of phase centers of an antenna arrangement having a transmitting antenna element and a receiving antenna element according to a second exemplary embodiment of one of the vehicle radar systems of FIG. 1 during operation in a short-range measurement mode, with the phase center of the transmitting antenna element shown alongside the phase center of the receiving antenna element. [Figure 16] FIG. 16 shows the arrangement of phase centers of the antenna arrangement of FIG. 15 and the arrangement of virtual phase centers of the corresponding virtual antenna array. [Figure 17] FIG. 17 shows two-dimensional antenna radiation patterns for the virtual antenna array of FIG. [Figure 18] FIG. 18 shows a horizontal pattern corresponding to the antenna radiation pattern of FIG. 17. [Figure 19] FIG. 18 shows the vertical pattern corresponding to the antenna radiation pattern of FIG. 17. [Figure 20] FIG. 16 illustrates an arrangement of phase centers of the antenna arrangement according to the first exemplary embodiment of FIG. 15 during operation in a long range measurement mode. [Figure 21] FIG. 21 shows the arrangement of phase centers of the antenna arrangement of FIG. 20 and the arrangement of virtual phase centers of the corresponding virtual antenna array. [Figure 22] FIG. 22 shows two-dimensional antenna radiation patterns for the virtual antenna array of FIG. 21. [Figure 23] FIG. 23 shows a horizontal pattern corresponding to the antenna radiation pattern of FIG. 22. [Figure 24] FIG. 23 shows the vertical pattern corresponding to the antenna radiation pattern of FIG. 22. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] In the figures, identical components are given the same reference numbers.

[0069] Fig. 1 shows a plan view of a vehicle 10 in the form of a car in a driving condition, and Fig. 2 shows the vehicle 10 in a side view.

[0070] The vehicle 10 is, by way of example, equipped with three radar systems 12 and a driver assistance system 14. The radar systems 12 are, by way of example, arranged at the front of the vehicle 10 in the direction of travel 16. The radar systems 12 can be used to monitor a monitoring area 18 in front of and diagonally ahead of the vehicle 10 for objects 20. Figure 3 shows a detailed plan view of the three radar systems 12, with the outline of the front part of the vehicle 10 indicated by dotted lines.

[0071] 1 and 2, an object 20 that can be detected using the radar system 12 is illustratively located in front of the vehicle 10.

[0072] The radar system 12 may be used to determine object information, such as distance D, direction, such as azimuth angle Θ and elevation angle Φ, and velocity, of a detected object 20 relative to the vehicle 10 .

[0073] The radar systems 12 are each operatively connected to a driver assistance system 14. Object information determined using the radar systems 12 may thus be transmitted to the driver assistance systems 14. The driver assistance systems 14 may be used to operate the vehicle 10 autonomously or at least semi-autonomously.

[0074] In addition to or as an alternative to the radar system 12 shown by way of example, radar systems may also be arranged in different positions and in different arrangements on the vehicle 10. For example, a radar system used to monitor a surveillance area behind or diagonally behind the vehicle 10 in the direction of travel 16 for objects 20 may also be arranged at the rear of the vehicle 10. Furthermore, a radar system may also be provided which may monitor a suitable surveillance area to the side of the vehicle 10 as a side radar system.

[0075] For simpler orientation, the applicable coordinates of the Cartesian xyz coordinate system are indicated in Figures 1-6, 10, 11, 15, 16, 20 and 21. By way of example, the x-axis of the xyz coordinate system extends parallel to the longitudinal vehicle axis 22 of the vehicle 10. The y-axis extends parallel to the transverse vehicle axis 24 of the vehicle 10, and the z-axis extends spatially upwards at right angles to the xy plane.

[0076] As an example, one of the radar systems 12 is located in the center of the front fender and is used as a front radar system, and the other two radar systems 12 are located opposite the front radar system 12 in each of the front corner regions of the vehicle 10. The two outer radar systems 12 are used as corner radar systems.

[0077] The antenna plane 26 of the forward radar system 12 extends perpendicular to the longitudinal vehicle axis 22 .

[0078] The antenna plane 26 of each of the radar systems 12 is an imaginary plane in which the phase centers 28 of the antenna elements of the respective radar system 12 are located, in particular the phase centers 28t of the transmitting antenna elements Tx and the phase centers 28r of the receiving antenna elements Rx. In the illustrated exemplary embodiment, the antenna planes 26 of the three radar systems 12 extend perpendicular to the xy plane, i.e. spatially vertically in normal operating conditions of the vehicle 10.

[0079] The right corner radar system 12 as viewed from the direction of travel 16 is rotated approximately 45° to the right such that its antenna plane 26 extends at an angle of approximately 45° relative to the vehicle longitudinal axis 22. The left corner radar system 12 as viewed from the direction of travel 16 is correspondingly tilted -45° to the left such that its antenna plane 26 is correspondingly tilted -45° to the left relative to the vehicle longitudinal axis 22.

[0080] The radar system 12 may be used to transmit a radar signal 30 into the monitored region 18. The radar signal 32 reflected from the object 20 in the direction of the radar system 12 may be received by the radar system 12 as an echo signal 32. Corresponding object information, specifically, the distance D, azimuth angle Θ, elevation angle Φ, and velocity of the detected object 20 relative to the vehicle 10, may be determined from the echo signal 32.

[0081] The radar systems 12 are of the same design and operate in the same way. The design of the radar system 12 is explained in more detail below as an example based on a forward radar system 12 with reference to FIG.

[0082] The radar system 12 comprises an antenna arrangement 34 having a transmitting antenna element Tx and a receiving antenna element Rx, and a control and detection device 36. The control and detection device 36 may be used to activate the transmitting antenna element Tx to emit a radar signal 30. Furthermore, the control and detection device 36 may be used to detect and evaluate echo signals 32 received by the receiving antenna element Rx. The control and detection device 36 may be used to determine corresponding object information from said echo signals and to transmit said information to the driver assistance system 14.

[0083] The antenna arrangement 34 comprises a number of transmit antenna elements Tx, only two of which are shown by way of example in Fig. 4, and a number of receive antenna elements Rx, only two of which are also shown by way of example. The radar system 12 can be operated both using multiple-in-multiple-out (MIMO) techniques and using beamforming techniques.

[0084] In the MIMO approach, the transmitting antenna elements Tx are individually activated using transmit control signals by the control and detection device 36. Appropriate transmit control signals are used to make the radar signals 30 distinguishable, for example by encoding, thus enabling the signal paths of the radar signals 30 and the corresponding echo signals 32 to be assigned to the respective transmitting antenna elements Tx at the receiving side.

[0085] In the beamforming method, multiple transmit antennas Tx are actuated together using a coherent transmit control signal with an appropriate phase shift, which may be zero. The individual radar signals emitted by each transmit antenna Tx may therefore interfere to form an overall radar signal 30. The applicable phase shift allows the direction of the main beam axis 42 of the radar signal 30 to be changed. A phase shifter 43 is assigned to each transmit antenna Tx to create the phase shift.

[0086] The control and detection device 36 comprises adjustment means 38 which can be used to adjust the intended use and measurement modes of the radar system 12 .

[0087] The intended use mode is adjusted based on the intended use of the corresponding radar system 12. In the case of the described vehicle 10, for example, three intended uses are shown for the radar system, specifically, as a front radar system 12, as a right corner radar system 12, or as a left corner radar system 12.

[0088] A measurement mode is a mode in which the radar system 12 performs radar measurements. Two measurement modes are described below, specifically, a long-range measurement mode and a short-range measurement mode, as examples.

[0089] In the long-range measurement mode, the radar system 12 is operated using a combination of MIMO and beamforming techniques, in which it is possible to detect an object 20 at a distance of up to approximately 200 m in the long-range field of view 40f of the radar system 12 as shown in FIG.

[0090] In the short-range measurement mode, the radar system 12 is operated using the MIMO method. In the short-range measurement mode, it is possible to detect objects 20 in a short-range field of view 40n, for example at a distance of up to 100 m. The short-range field of view 40n has a beam angle that is much larger than the beam angle of the long-range field of view 40f.

[0091] In order to be able to identify objects 20 ahead of the vehicle in the direction of travel 16 at an early stage, the principal main beam axis 42 of the antenna arrangement 34 in the long-range measurement mode should be aligned approximately parallel to the direction of travel 16, e.g. approximately parallel to the vehicle longitudinal axis 22, regardless of the intended use of the radar system 12 as a front radar system 12 or a corner radar system 12. The principal main beam axis 42 defines the alignment of the long-range field of view 40f and the main propagation direction of the transmitted radar signal 30 in the basic configuration of the radar system 12 for the applicable intended use.

[0092] During the radar measurement, it is also possible to optionally change, for example rotate, the propagation direction of the radar signal 30 in the long-range measurement mode relative to the fundamental main beam axis 42 .

[0093] Adaptation of the alignment of the principal main beam axis 42 based on the intended use of the radar system 12 as a forward radar system or a corner radar system is defined using the adjustment means 38 over the intended mode of use.

[0094] The adjustment means 38 includes, by way of example, three basic control schemes 44, two measurement control schemes 46, and, by way of example, three intended use variables 48.

[0095] Each measurement control scheme 46 contains a specification according to which a transmission control signal is sent to the transmitting antenna element Tx according to a desired measurement mode. By way of example, one measurement control scheme 46 for a long-range measurement mode and one measurement control scheme 46 for a short-range measurement mode are provided.

[0096] The basic control schemes 44 each contain specifications according to which applicable transmit control signals are transmitted to the transmit antenna elements Tx in the long range measurement mode in order to align the basic main beam axis 42 .

[0097] Each intended use variable 48 characterizes an intended use of the radar system 12. By way of example, the use variables 48 can be stored in the memory of the control and detection device 14. By way of example, each intended use variable 48 is a phase shift. In the beamforming method, to implement a long-range measurement mode, the transmitting antenna elements Tx can be operated together using coherent transmit signals, between which the applicable phase shifts identified as intended use variables 48 are adjusted. The applicable phase shifts allow the principal main beam axis 42 to be aligned with respect to the antenna plane 26 of the radar system 12 in order to adapt the principal main beam axis 42 to the intended use of said radar system.

[0098] By way of example, a basic control scheme 44 and intended use variables 48 for use of the radar system 12 as a forward radar system, a basic control scheme 44 and intended use variables 48 for use as a left corner radar system, and a basic control scheme 44 and intended use variables 48 for use as a right corner radar system may be provided to the adjustment means 38.

[0099] The intended use mode may be adjusted by implementing the basic control scheme 44 with the applicable intended use variables 48. As an example, the basic control scheme 44 for the right corner radar system 12 may include actuating the transmit antenna element Tx using coherent transmit control signals that are phase shifted by a particular phase offset, so that the fundamental main beam axis 42 of the resulting radar signal 30 is rotated -45° relative to the antenna plane 26. The 45° rotated alignment of the corner radar system 12 may thus be corrected to align the fundamental main beam axis 42 parallel to the direction of travel 16 or the vehicle longitudinal axis 22.

[0100] Depending on the arrangement of the transmitting antenna elements Tx and the intended use of the radar system 12, the phase shift may also be zero.

[0101] The applicable intended use variables 48 may be adjusted during or prior to installation of the radar system 12 on the vehicle 10. More or fewer than three intended use variables 48 may also be stored in the radar system 12. For example, intended use variables for use on different vehicles and / or at different positions and / or at different orientations on the vehicle may thus be provided. The radar system 12 may thus be used generically and appropriately adapted for different vehicles and different uses on or within the vehicle.

[0102] The adjustment means 38 is implemented in the control and detection unit 36, for example using software. Thus, there is no need to modify the hardware of the radar system 12 in order to adapt the radar system 12 to different intended uses.

[0103] The operation of the radar system 12 having the antenna arrangement 34 according to the first exemplary embodiment will be described in more detail below in a short-range measurement mode with reference to Figures 5-9 and in a long-range measurement mode with reference to Figures 10-14.

[0104] 5 and the lower part of FIG. 6 show the phase center 28t of the transmitting antenna element Tx and the phase center 28r of the receiving antenna element Rx of the antenna arrangement 34. For better clarity, FIG. 5 shows the transmitting antenna arrangement 34t on the left side separately from the receiving antenna arrangement 34r on the right. The transmitting antenna arrangement 34t and the receiving antenna arrangement 34r may also be arranged differently from each other. The transmitting antenna arrangement 34t and the receiving antenna arrangement 34r may also overlap, as shown in the lower part of FIG. 6. For better distinction, the phase center 28t of the transmitting antenna element Tx is depicted here using a circle and the phase center 28r of the receiving antenna element Rx is depicted using a black triangle.

[0105] The transmitting antenna arrangement 24s comprises four transmitting antenna elements Tx. The phase centre 28t is located on an imaginary transmitting antenna axis 50. The transmitting antenna axis 50 extends in the antenna plane 26, for example horizontally and parallel to the xy plane.

[0106] Four phase centers 28t are arranged in two transmitting antenna groups SG. A distance 52 between the phase centers 28t of the same transmitting antenna group SG corresponds to approximately half the wavelength λ of the radar signal 30 emitted by the transmitting antenna element Tx. A distance 54 between the phase centers 28t of two transmitting antenna elements Tx on the side facing the two transmitting antenna groups SG is approximately 3 / 2 the wavelength λ.

[0107] The receive antenna arrangement 34r comprises a total of four receive antenna elements Rx. Three of the phase centers 28r are located on a first receive antenna axis 56. In the illustrated exemplary embodiment, the first receive antenna axis 56 extends coaxially with the transmit antenna axis 50 of the transmit antenna arrangement 34t in the antenna plane 26.

[0108] The three transmit antenna elements Tx on the first receive antenna axis 56 form three groups.

[0109] 5 and 6 , the distance 58 between the left and middle phase centers 28r of the three groups of the first receive antenna axis 56 corresponds to approximately the wavelength λ of the radar signal 30. The distance 60 between the phase center 28r of the middle receive antenna element Rx and the phase center 28r of the right receive antenna element Rx corresponds to approximately 3 / 2 the wavelength λ of the radar signal 30.

[0110] The phase center 28r of the fourth receive antenna element Rx is located on a second receive antenna axis 62. The second receive antenna axis 62 extends parallel to the first receive antenna axis 56 in the antenna plane 26. A distance 64 between the first receive antenna axis 56 and the second receive antenna axis 62 corresponds to the wavelength λ of the radar signal 30.

[0111] A perpendicular line 66 passing through the phase center 28r of the fourth receive antenna element Rx relative to the first receive antenna axis 56 is located outside the group of three phase centers 28r of the receive antenna elements Rx of the first receive antenna axis 56. In Figures 5 and 6, the phase center 28r of the receive antenna element Rx of the second receive antenna axis 62 is shifted to the left relative to the group of three phase centers 28r of the first receive antenna axis 56.

[0112] A distance 68 between a perpendicular 66 to the first receive antenna axis 56 that passes through the phase center 28r of the second receive antenna axis 62 and the phase center 28r of the receive antenna element Rx on the left side of the first receive antenna axis 56 in Figure 5 corresponds to half the wavelength λ of the radar signal 30.

[0113] In the short-range measurement mode, the radar system 12 is operated according to the MIMO method, which involves the transmit antenna elements Tx being operated individually, for example using transmit control signals that are coded relative to each other, so that they emit distinguishable radar signals 30.

[0114] A geometric folding of the geometric locations of the phase centers 28t of the transmitting antenna elements Tx and the phase centers 28r of the receiving antenna elements Rx is used to generate a virtual antenna array 70 shown at the top of Figure 6. The virtual phase centers 72 of the virtual antenna elements of the virtual antenna array 70 are indicated as black squares in Figure 6.

[0115] According to the first exemplary embodiment, during operation of the radar system 12 in the short-range measurement mode, a total of 14 virtual antenna elements with corresponding virtual phase centers 72 are generated for the antenna arrangement 34. The virtual phase centers 72 are arranged on a first virtual antenna axis 74 and a second virtual antenna axis 76. The virtual antenna axes 74 and 76 extend in the antenna plane 26 parallel to the transmitting antenna axes 50, 56 and 62. The distribution of the virtual phase centers 72 along each of the virtual antenna axes 74 and 76 allows the azimuth angle Θ to be determined. The distribution of the virtual phase centers 72 across the two spaced apart virtual antenna axes 74 and 76, i.e. across the two elevation planes, allows the elevation angle Φ to be ascertained.

[0116] The distance 78 between the virtual phase center 72 of the second virtual antenna axis 74, which is located at the leftmost position in FIG. 6, and the virtual phase center 72 of the first virtual antenna axis 74, which is located at the rightmost position, defines the aperture of the antenna arrangement 34.

[0117] FIG. 7 shows, by way of example, a two-dimensional antenna radiation pattern for a virtual antenna array 70 in the near field measurement mode using the MIMO method, in grey scale in two dimensions, the elevation angle Φ and the azimuth angle Θ. The assignment of the grey scale to normalized intensity is shown on the intensity scale on the right side in dB. The azimuth angle Θ is shown along the horizontal axis, in degrees. The elevation angle Φ is also shown along the vertical axis, in degrees.

[0118] Figure 8 shows the horizontal pattern corresponding to the two-dimensional antenna radiation pattern of Figure 7 as a function of azimuth angle Θ at elevation angle Φ = 0° along section line VIII of Figure 7. A normalized intensity curve 80 for the virtual array 70 is shown in Figure 8 using a solid line 80. Purely for comparison, a normalized intensity curve 82 for the transmit antenna arrangement 34t is shown using a dashed line. A normalized intensity curve 84 for the receive antenna arrangement 34r is shown using a dotted line.

[0119] FIG. 9 shows the vertical pattern corresponding to the two-dimensional antenna radiation pattern of FIG. 7 as a function of elevation angle Φ at azimuth angle Θ=0° along the reproduced section line IX of FIG.

[0120] The operation of the radar system 12 having the antenna arrangement 34 according to the first exemplary embodiment in the long-range measurement mode will be explained in more detail below in view of Figures 10 to 14. The antenna arrangement 34 is shown in Figure 10, or in the lower part of Figure 11. The transmitting antenna arrangement 34t and the receiving antenna arrangement 34r are shown next to each other in Figure 10, similar to the depiction in Figure 5. Figure 11 shows the antenna arrangement 34, similar to the depiction in Figure 6.

[0121] In the long range measurement mode, a combination of the MIMO method and the beamforming method described in relation to figures 5 to 9 is carried out, which is hereinafter called the "MIMO / beamforming method". This involves that the transmitting antenna elements Tx of the same transmitting antenna group SG are activated using the same coherent transmit control signal with a phase shift specified by the variable 48 of the intended use. The fundamental main beam axis 42 is adjusted according to the intended use by specifying the appropriate phase shift.

[0122] The two transmit antenna groups SG are operated using different transmit control signals, for example coded relative to each other, so that the echo signals 32 of the radar signal 30 transmitted by the two transmit antenna groups SG can be assigned to the respective transmit antenna groups SG by the receive antenna elements Rx.

[0123] A group phase center 28SG, geometrically located between the individual phase centers 28t of the transmitting antenna elements Tx of the respective transmitting antenna group SG, is implemented for each transmitting antenna group SG. The distance 86 between the group phase centers 28SG is approximately twice the wavelength λ of the transmitted radar signal 30.

[0124] A geometric folding of the positions of the phase centers 28SG of the groups of the transmitting groups SG and the receiving phase centers 28r of the receiving antenna elements Rx in the MIMO / beamforming method is used to implement a virtual array 70, whose virtual phase centers 72 are shown in the upper part of FIG. 11. The total number of virtual array elements with virtual phase centers 72 shown in FIG. 11 amounts to eight, and is therefore less than the total number of virtual array elements in the MIMO method described in connection with FIGS. 5 to 9. This increases the side lobe levels. This is evident from the antenna radiation patterns in FIGS. 12 and 13. However, a larger range, required in the long distance measurement mode, is also achieved.

[0125] FIG. 12 shows, by way of example, a two-dimensional antenna radiation pattern for a virtual antenna array 70 in a long-range measurement mode using a MIMO / beamforming method, in grey scale in two dimensions, elevation angle Φ and azimuth angle Θ. The assignment of the grey scale to normalized intensity is shown on the intensity scale on the right side in dB. The azimuth angle Θ is shown along the horizontal axis, in degrees. The elevation angle Φ is also shown along the vertical axis, in degrees.

[0126] Figure 13 shows the horizontal pattern corresponding to the two-dimensional antenna radiation pattern of Figure 12 as a function of azimuth angle Θ at elevation angle Φ = 0° along section line XIII reproduced in Figure 12. A normalized intensity curve 80 for the virtual array 70 is shown in Figure 13 using a solid line 80. Purely for comparison, a normalized intensity curve 82 for the transmitting antenna arrangement 34t is shown using a dashed line. A normalized intensity curve 84 for the receiving antenna arrangement 34r is shown using a dotted line.

[0127] FIG. 14 shows the vertical pattern corresponding to the two-dimensional antenna radiation pattern of FIG. 12 as a function of elevation angle Φ at azimuth angle Θ=0° along section line XIV reproduced in FIG.

[0128] The operation of the radar system 12 with the antenna arrangement 34 according to the second exemplary embodiment is explained in more detail below with reference to Figures 15 to 19 in a short-range measurement mode using MIMO techniques, and with reference to Figures 20 to 24 in a long-range measurement mode using MIMO / beamforming techniques. Elements similar to those of the first exemplary embodiment of Figures 6 to 14 are given the same reference numerals.

[0129] The antenna arrangement 34 according to the second exemplary embodiment shown in FIG. 15 and at the bottom of FIG. 16 differs from the antenna arrangement 34 according to the first exemplary embodiment of FIG. 5 and FIG. 6 in that the phase center 28r of the right-hand receiving antenna element Rx in FIG. 15 is located on the third receiving antenna axis 88 instead of the first receiving antenna axis 56.

[0130] The third receive antenna axis 88 extends parallel to the first receive antenna axis 56 on the opposite side of the first receive antenna axis 56 from the second receive antenna axis 62. The third receive antenna axis 88 is also located in the antenna plane 26.

[0131] The distance 90 between the first receive antenna axis 56 and the third receive antenna axis 90 corresponds to the distance 64 between the first receive antenna axis 56 and the second receive antenna axis 62. The distance 90 corresponds approximately to the wavelength λ of the emitted radar signal 30.

[0132] A distance 92 between a perpendicular line 94 passing through the phase center 28r of the receiving antenna element Rx of the third receiving antenna axis 88 to the first antenna axis 56 and the phase center 28r of an adjacent receiving antenna element Rx, specifically the right phase center 28r of the first receiving antenna axis 56, corresponds to approximately the wavelength λ of the emitted radar signal 30.

[0133] The perpendicular line 94 is located outside the region of the phase centers 28r of the two inner receive antenna elements Rx of the first receive antenna axis 56. The perpendicular line 94 passing through the phase center 28r of the third receive antenna axis 88 is located on the opposite side of the region including the two middle receive antenna centers 28r of the first receive antenna axis 56 from the perpendicular line 66 passing through the first phase center 28r of the second receive antenna axis 94.

[0134] FIG. 16 shows the phase center 28 of the antenna arrangement 34 according to the second exemplary embodiment at the bottom and the corresponding virtual array 70 at the top during operation of the radar system 12 in a short-range measurement mode using MIMO techniques.

[0135] The upper part of FIG. 16 shows a virtual phase center 72 of a virtual array 70 that is part of the antenna arrangement 34 according to the second exemplary embodiment in a short-range measurement mode.

[0136] The spread 96 of the virtual array 70 in elevation, extending parallel to the z-axis, is greater than the corresponding spread 96 of the first exemplary embodiment antenna arrangement 34 of Figures 5-14. In addition to measuring the elevation angle Φ, the second exemplary embodiment antenna arrangement 34 can be used to achieve an elevation resolution capable of separating two detected objects.

[0137] The middle columns of the virtual array 70 are fully occupied in the azimuth direction Θ, e.g., in the y-axis direction, which reduces the side lobe levels.

[0138] 17 shows, by way of example, a two-dimensional antenna radiation pattern for the virtual antenna array 70 according to the second exemplary embodiment in the near field measurement mode using the MIMO method, in gray scale in two dimensions, the elevation angle Φ and the azimuth angle Θ. The assignment of the gray scale to normalized intensity is shown on the intensity scale on the right side in dB. The azimuth angle Θ is shown along the horizontal axis, in degrees. The elevation angle Φ is also shown along the vertical axis, in degrees.

[0139] Figure 18 shows the horizontal pattern corresponding to the two-dimensional antenna radiation pattern of Figure 17 as a function of azimuth angle Θ at elevation angle Φ = 0° along section line XVIII of Figure 17. A normalized intensity curve 80 for the virtual array 70 is shown in Figure 18 using a solid line 80. Purely for comparison, a normalized intensity curve 82 for the transmitting antenna arrangement 34t is shown using a dashed line. A normalized intensity curve 84 for the receiving antenna arrangement 34r is shown using a dotted line.

[0140] FIG. 19 shows the vertical pattern corresponding to the two-dimensional antenna radiation pattern of FIG. 17 as a function of elevation angle Φ at azimuth angle Θ=0° along section line XIX of FIG.

[0141] The operation of the radar system 12 having the antenna arrangement 34 according to the second exemplary embodiment in a long range measurement mode using MIMO / beamforming techniques will be described in detail below with reference to FIGS. 20 to 24.

[0142] In the long distance measurement mode, the transmitting antenna element Tx is operated similarly to the operation in the long distance measurement mode with the antenna arrangement 34 according to the first exemplary embodiment of FIGS.

[0143] The resulting virtual phase centers 72 of the virtual antenna array 70 are shown in the upper part of Figure 21. As in the case of operation of the radar system 12 having the antenna arrangement 34 according to the second exemplary embodiment in the short-range measurement mode shown in Figures 15-19, the virtual phase centers 72 are distributed over three elevation planes.

[0144] The operation of the transmitting antenna elements Tx in groups reduces the total number of virtual antenna arrays 70 to eight. This increases the strength of the sidelobe levels, as shown in Figures 22 to 24. Beamforming in the MIMO / Beamforming method, however, allows a larger range, given a substantially unchanged angular resolution, compared to operation in the short range measurement mode.

[0145] FIG. 22 shows, by way of example, a two-dimensional antenna radiation pattern for a virtual antenna array 70 in a long-range measurement mode using a MIMO / beamforming method, in grey scale in two dimensions, elevation angle Φ and azimuth angle Θ. The assignment of the grey scale to normalized intensity is shown on the intensity scale on the right side in dB. The azimuth angle Θ is shown along the horizontal axis, in degrees. The elevation angle Φ is also shown along the vertical axis, in degrees.

[0146] Figure 23 shows the horizontal pattern corresponding to the two-dimensional antenna radiation pattern of Figure 22 as a function of azimuth angle Θ at elevation angle Φ=0° along section line XXIII of Figure 22. A normalized intensity curve 80 for the virtual array 70 is shown in Figure 23 using a solid line 80. Purely for comparison, a normalized intensity curve 82 for the transmitting antenna arrangement 34t is shown using a dashed line. A normalized intensity curve 84 for the receiving antenna arrangement 34r is shown using a dotted line.

[0147] FIG. 24 shows the vertical pattern corresponding to the two-dimensional antenna radiation pattern of FIG. 22 as a function of elevation angle Φ at azimuth angle Θ=0° along section line XXIV of FIG.

[0148] As can be seen from Figures 18 and 23, the full width at half maximum 98 of the main lobe in the direction of azimuth angle Θ at the 3 dB limit is 10.5° in the antenna arrangement 34 according to the second exemplary embodiment. In the antenna arrangement 34 according to the first exemplary embodiment, as can be seen from Figures 7 and 13, the corresponding full width at half maximum 98 in the direction of azimuth angle Θ is only 9.5°.

[0149] In the antenna arrangement 34 according to the second exemplary embodiment, the full width at half maximum 100 of the main lobe in the direction of the elevation angle Φ at the 3 dB limit is 21°, as can be seen from Figures 19 and 24. In the antenna arrangement 34 according to the first exemplary embodiment, the corresponding full width at half maximum 100 in the direction of the elevation angle Φ at the 3 dB limit is 35.5°, as can be seen from Figures 9 and 14.

Claims

1. A method of operating a radar system (12) for a vehicle (10), the radar system (12) being used to perform at least one radar measurement involving using at least one transmitting antenna element (Tx) of at least one transmitting antenna arrangement (34t) of the radar system (12) to transmit at least one radar signal (30) and arming at least one receiving antenna element (Rx) of at least one receiving antenna arrangement (34r) of the radar system (12) to receive any radar return signals (32) based on the at least one radar signal (30), the at least one transmitting antenna element (Tx) being operated according to at least one control scheme (44, 46), a basic control strategy (44) for the radar system (12), which is specified according to an intended use of the radar system (12) on the vehicle (10), is adjusted for at least one measurement mode of the radar system (12) at the latest at the start of one radar measurement, the basic control strategy (44) is used to adapt a basic main beam axis (42) of the at least one transmitting antenna arrangement (34t) to the intended use of the radar system (12), and the at least one radar measurement is performed starting from the basic control strategy (44).

2. 2. The method of claim 1, wherein at least two transmit antenna elements (Tx) of at least one transmit antenna arrangement (34t) are operated using respective transmit control signals to emit respective mutually coherent individual radar signals that are superimposed to form the at least one radar signal (30), and wherein in the basic control scheme (44) for the radar system (12), a basic phase shift between the respective transmit control signals, which may be zero, is specified for the at least two transmit antenna elements (Tx).

3. 3. The method according to claim 1 or 2, characterized in that a phase shift, in particular a basic phase shift, between the respective transmit control signals is adjusted by at least one phase shifter (43) and / or a phase shift which is linearly proportional to the distance (52) between the at least two transmit antenna elements (Tx) is adjusted.

4. at least one basic control strategy (44) is adjusted using at least one intended use variable (48) characterizing an intended use, said at least one intended use variable (48) being specified in a control device (36) for said radar system (12), in particular in the control device (36) of said radar system (12), at the latest when said radar system (12) is mounted on said vehicle (10), and / or 4. The method according to claim 1, wherein at least one basic control strategy (44) is adjusted in a control device (36) for the radar system (12), in particular in a control device (36) of the radar system (12).

5. the basic control scheme (44) is used to adapt the basic main beam axis (42) to the intended use in a long range measurement mode of the radar system (12); and / or the radar system (12) is operated in different distance measuring modes, in particular a long distance measuring mode and a short distance measuring mode, alternately or at least partially overlapping in time, and / or At least one of the transmitting antenna elements (Tx) is operated in a number of different distance measurement modes to transmit radar signals (30) and / or a number of receiving antenna elements (Rx) of at least one receiving antenna arrangement (34r) are armed to receive echo signals (32).

5. The method according to claim 1, wherein the

6. the radar system (12) is operated at least temporarily using a control scheme (44, 46) based on a beamforming method and / or at least temporarily using a control scheme (44, 46) based on a MIMO method, and / or The at least one transmitting antenna arrangement (34t) is at least temporarily activated in at least two transmitting antenna groups (SG), the transmitting antenna elements (Tx) in one transmitting antenna group (SG) are activated together, and the transmitting antenna groups (SG) are activated individually.

6. The method according to claim 1 , characterized in that

7. At least one respective corresponding basic control strategy (44) is specified for use of the radar system (12) as a front radar system (12), a corner radar system, a side radar system, and / or a rear radar system; and / or said basic control method (44) is used for aligning said basic main beam axis (42) of said at least one transmitting antenna arrangement (34t) with respect to at least one vehicle reference field, in particular with respect to the vehicle longitudinal axis (22); and / or The basic control method (44) is used to align the basic main beam axis (42) of the at least one transmitting antenna arrangement (34t) with respect to at least one radar system reference region (26), in particular with respect to an antenna plane.

7. The method according to claim 1, wherein the

8. 8. The method according to claim 1, wherein the at least one radar measurement involves ascertaining at least one directional variable (Θ, Φ) characterizing at least one direction of the at least one object reflecting the at least one transmitted radar signal to the radar system in at least one dimension and / or ascertaining at least one distance variable (D) characterizing at least one distance of the at least one object reflecting the at least one transmitted radar signal to the radar system and / or ascertaining at least one velocity variable characterizing at least one velocity of the at least one object reflecting the at least one transmitted radar signal to the radar system.

9. 9. The method according to claim 1, wherein a plurality of transmitting antenna elements (Tx) of an antenna arrangement (34) are activated to transmit radar signals (30) and a plurality of receiving antenna elements (Rx) of the antenna arrangement (34) are put into standby to receive echo signals (32), and a geometric folding of the geometric positions of the transmitting antenna elements (Tx) and the receiving antenna elements (Rx) of the antenna arrangement (34) is used to determine a corresponding virtual receiving antenna array (70).

10. 10. A radar system (12) for a vehicle (10) having at least one transmitting antenna arrangement (34t) with at least one transmitting antenna element (Tx) for transmitting a radar signal (30), at least one receiving antenna arrangement (34r) with at least one receiving antenna element (Rx) for receiving a radar return signal (32), and at least one control and detection device for actuating at least the transmitting antenna element (Tx) and for detecting the radar return signal (32) received by the at least one receiving antenna element (Rx), wherein the radar system (12) has at least one adjusting means (38) with at least one control scheme (44, 46) for adjusting at least one main beam axis (42) of the at least one transmitting antenna arrangement (34t), characterized in that the radar system (12) has means for performing the method according to any one of claims 1 to 9.

11. A vehicle (10) having at least one radar system (12), characterized in that the vehicle (10) has at least one radar system (12) having means for carrying out the method according to any one of claims 1 to 9.

Images