Vehicle radar system
By generating radar signal ramp sequences with different phase shift increments for each transmitter antenna in the vehicle radar system and applying artificial Doppler modulation, detection errors caused by Doppler frequency conflict are resolved, and more accurate target detection is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MAGNA ELECTRONICS SWEDEN AB
- Filing Date
- 2024-09-24
- Publication Date
- 2026-04-21
AI Technical Summary
Existing vehicle radar systems suffer from detection errors due to Doppler frequency conflicts when detecting multiple targets, especially the inability to distinguish overlapping targets within the same Doppler chamber.
By generating radar signal ramp sequences with different phase shift increments for each transmitter antenna in the vehicle radar system, applying artificial Doppler modulation, and processing the signals using a programmable phase shifter and a digital signal processor, accurate detection of the target object can be achieved.
It effectively reduces the error when different target objects overlap in the same Doppler chamber, and improves the detection accuracy and discrimination ability of target objects.
Smart Images
Figure CN121909406A_ABST
Abstract
Description
Summary of the Invention
[0001] This disclosure relates to a vehicle radar system including a control unit, a plurality of transmitter antenna arrangements, and a transceiver unit, the transceiver unit further including a transmitter unit arranged to generate an FMCW (Frequency Modulated Continuous Wave) radar waveform. Each radar waveform includes at least two corresponding consecutive sequences of radar signal ramps, and wherein the transmitter unit is adapted to feed the corresponding radar waveform to each of at least two transmitter antenna arrangements.
[0002] A radar system includes means for generating a radar signal that is transmitted, reflected, and received using a suitable antenna included in the radar system. The signal may include a so-called chirped ramp in an FMCW (Frequency Modulated Continuous Wave) signal with a specific amplitude, wherein the frequency slopes continuously between two values, thus the chirped signal is in the form of a continuous sine wave, where the frequency changes from a first low frequency to a second high frequency during the ramp.
[0003] Such radar systems can take the form of a multiple-input multiple-output (MIMO) radar, as disclosed in document US 2011140949, which describes a MIMO radar in which the transmitter transmits an FMCW signal and the receiver receives the echo signal mixed with the transmitted signal. The mixed signal is then converted into a digital signal.
[0004] MIMO enables simultaneous transmission from multiple transmitters, with signals extracted from each transmitter upon reception. A common technique for performing this operation on FMCW signals is DDMA (Doppler Division Multiple Access). This technique uses programmable phase shifters for each transmitter to modulate an artificial Doppler frequency onto each transmitted signal. Because the two transmitters do not use the same modulated artificial Doppler frequency, each transmitter is found to be located at a different position in the Doppler spectrum. DDMA requires that the modulated Doppler frequency be known for the detection signal in the Doppler spectrum used for a particular transmitter.
[0005] If there are two or more objects that are not resolved by range FFT and have different relative velocities and therefore different Doppler frequencies, an artificially Doppler modulated transmission signal from one object may collide with an artificially Doppler modulated transmission signal from another object. If this occurs, a subset of the received signal is contaminated by the signal from the other object, thus introducing errors in subsequent processing steps (e.g., bearing processing). Typically, the frame rate of a radar device (i.e., the time from one FMCW pulse to the next) is so small that environmental conditions remain almost constant in subsequent FMCW pulses, thus resulting in collisions in subsequent frames. This leads to the same errors in subsequent processing steps within subsequent frames.
[0006] The purpose of this disclosure is to provide a vehicle radar system that is arranged to counteract the aforementioned problems.
[0007] This objective is achieved using a vehicle radar system comprising a control unit and a transceiver unit, the transceiver unit further comprising a plurality of transmitter antenna arrangements and transmitter units arranged to generate FMCW (Frequency Modulated Continuous Wave) radar waveforms. Each radar waveform comprises at least two corresponding consecutive sequences of a radar signal ramp, and the transmitter units are adapted to feed the corresponding radar waveforms to each of the at least two transmitter antenna arrangements. For each of the at least two transmitter antenna arrangements, the transmitter units are adapted to generate adjacent sequences of radar signal ramps with different phase shift increments, such that artificial Doppler modulation is applied to each sequence of the radar signal ramps.
[0008] This means reducing the probability of detecting different target objects that overlap at the same Doppler chamber to the point that two detections cannot distinguish them.
[0009] According to some aspects, the transmitter unit includes a signal generator and a phase shifter, wherein the signal generator is connected to the phase shifter, which in turn is connected to the transmitter antenna arrangement. The phase shifter is a programmable phase shifter adapted to modulate an artificial Doppler frequency onto an FMCW radar waveform.
[0010] This provides accurate and easily controllable phase shifts.
[0011] Depending on some aspects, the transceiver unit may also include a receiver unit and a plurality of receiver antenna arrangements adapted to receive signals reflected by one or more target objects.
[0012] According to some aspects, the control unit includes a digital signal processor (DSP) arrangement adapted to process digital signals input from the receiver unit. According to some other aspects, the control unit is adapted to distinguish the received signals by finding signal patterns induced by artificial Doppler modulation, which are associated with different detected target objects in the Doppler spectrum.
[0013] This means that the well-known FDMM technique can be used to parse the target object.
[0014] According to some aspects, the receiver unit is arranged to convert the mixed received signals into digital signals.
[0015] In some respects, the control unit is suitable for controlling signal generators, phase shifters, and receiver units. This means that these devices are controlled in a highly efficient and centralized manner.
[0016] In some respects, the control unit is adapted to control the phase shifter so that each phase shift increment changes randomly between adjacent transmission sequences on the radar signal ramp. This facilitates distributed detection over time, thereby enabling more accurate detection of targets.
[0017] This objective is also achieved using methods and vehicles associated with the aforementioned advantages. Attached Figure Description
[0018] This disclosure will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 A schematic top view of the vehicle is shown; Figure 2 A simplified schematic diagram of a vehicle radar system is shown schematically. Figure 3A A graphical representation of the first FMCW radar waveform is illustrated schematically; Figure 3B A graphical representation of the second FMCW radar waveform is illustrated schematically; Figure 3C A graphical representation of the third FMCW radar waveform is illustrated schematically; Figure 3D A graphical representation of the fourth FMCW radar waveform is illustrated schematically; Figure 4A A first graphical representation of the spectral amplitude as a function of the Doppler spectral chamber used to detect the first object is schematically illustrated. Figure 4B A first graphical representation of the spectral amplitude as a function of the Doppler spectral chamber used to detect the second object is schematically illustrated. Figure 4C schematically shown Figure 4A and Figure 4B The combination of detections in; Figure 5A A second graphical representation of the spectral amplitude as a function of the Doppler spectral chamber used to detect the first object is schematically illustrated. Figure 5B A second graphical representation of the spectral amplitude as a function of the Doppler spectral chamber used to detect the second object is schematically illustrated. Figure 5C An illustrative example Figure 5A and Figure 5B The combination of detections in; Figure 6 The control unit is illustrated schematically; Figure 7 The computer program product is illustrated schematically; and Figure 8 A flowchart of the method according to this disclosure is shown. Detailed Implementation
[0019] The inventive concept will now be described more fully below with reference to the accompanying drawings, in which some embodiments of the inventive concept are illustrated. However, the inventive concept can be embodied in many different forms and should not be construed as limited to the embodiments listed herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Throughout the specification, the same reference numerals refer to the same elements. Any step or feature shown by dashed lines should be considered optional.
[0020] Figure 1 A vehicle 100 equipped with a vehicle radar system 101 is shown. The vehicle radar system 101 includes a control unit 130 and a transceiver unit 110, which in turn includes a plurality of transmitter antenna arrangements 210a, 210b, 210c, 210d. See also... Figure 2 and Figures 3A to 3D The transceiver unit 110 further includes a transmitter unit 208, which is arranged to generate radar waveforms in the form of FMCW, frequency-modulated continuous wave radar waveforms 204a, 204b, 204c, 204d, wherein each radar waveform 204a, 204b, 204c, 204d includes at least two corresponding consecutive sequences 241, 242; 243, 244; 245, 246; 247, 248 of the radar signal ramp r.
[0021] The transmitter unit 208 is adapted to feed the corresponding radar waveforms 204a, 204b, 204c, 204d to each of at least two transmitter antenna arrangements 210a, 210b, 210c, 210d.
[0022] The vehicle radar system 101 can be included in a single physical unit, or it can be distributed across more than one physical unit. Some parts of the radar system functionality can even be included in a remote server 160 or a cloud-based resource 170 connected to the vehicle 100 via a wireless link 150.
[0023] According to some aspects, transceiver unit 110 also includes receiver unit 212 and a plurality of receiver antenna arrangements 213a, 213b, 213c, 213d, adapted to receive signals 205 reflected by one or more target objects 140, 141. According to some aspects, vehicle radar system 101 is arranged to generate and transmit radar signals (sometimes also called radar chirp signals) in the form of FMCW signals 204a-204d, and to receive reflected radar signals 205, wherein the transmitted signals have been reflected by target objects 140, 141.
[0024] The vehicle radar system 101 is associated with a field of view 120. In the case of a forward vehicle radar system, the radar's line of sight 121 typically coincides with the centerline of the field of view 120 in the forward direction of the vehicle 100. If the vehicle radar system 101 is alternatively or otherwise configured as a side radar or a rear corner radar, the line of sight may point to some other angle relative to the forward direction of the vehicle 100.
[0025] As described above, the vehicle radar system 101 can be connected to a remote server 160 via a wireless link 150, which can then be included in a cloud-based resource 170 or a remote network. The server and network can be configured to assist the vehicle 100 in performing various operations, such as radar signal processing, interference mitigation, beamforming, etc.
[0026] According to this disclosure, for each of at least two transmitter antenna arrangements 210a, 210b, 210c, 210d, transmitter unit 208 is adapted to generate adjacent sequences 241, 242; 243, 244; 245, 246; 247, 248 of radar signal ramp r, which have different phase shift increments Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8, such that artificial Doppler modulation is applied to each sequence 241, 242; 243, 244; 245, 246; 247, 248 of radar signal ramp r.
[0027] This means reducing the probability of detecting different target objects that overlap at the same Doppler chamber to the point that two detections cannot distinguish them.
[0028] exist Figure 2 and Figures 3A to 3D In the example shown, there are four transmitter antenna arrangements 210a, 210b, 210c, and 210d. The first transmitter antenna arrangement 210a is adapted to transmit a first radar waveform 204a, which includes a first sequence 241 of radar signal ramps r and a second sequence 242 of radar signal ramps r. In the first sequence, a first phase increment ΔΔω1 exists between consecutive ramps r, and in the second sequence, a second phase increment ΔΔω2 exists between consecutive ramps r. The first phase increment ΔΔω1 is different from the second phase increment ΔΔω2.
[0029] Correspondingly, the second transmitter antenna arrangement 210b is adapted to transmit a second radar waveform 204b, which includes a third sequence 243 and a fourth sequence 244 of radar signal ramps r. In the third sequence, a third phase increment Δω3 exists between consecutive ramps r, and in the fourth sequence, a fourth phase increment Δω4 exists between consecutive ramps r. The third phase increment Δω3 is different from the fourth phase increment Δω4.
[0030] Correspondingly, the third transmitter antenna arrangement 210c is adapted to transmit a third radar waveform 204c, which includes a fifth sequence 245 and a sixth sequence 246 of radar signal ramp r. In the fifth sequence, a fifth phase increment Δω5 exists between consecutive ramp r, and in the sixth sequence, a sixth phase increment Δω6 exists between consecutive ramp r. The fifth phase increment Δω5 is different from the sixth phase increment Δω6.
[0031] Correspondingly, the fourth transmitter antenna arrangement 210d is adapted to transmit a fourth radar waveform 204d, which includes a seventh sequence 247 and an eighth sequence 248 of radar signal ramp r. In the seventh sequence, a seventh phase increment Δω7 exists between consecutive ramp r, and in the eighth sequence, an eighth phase increment Δω8 exists between consecutive ramp r. The seventh phase increment Δω7 is different from the eighth phase increment Δω8.
[0032] According to some aspects, this means that the control unit 130 is adapted to change a set of artificial Doppler modulation frequencies used for transmitter antenna arrangements 210a, 210b, 210c, 210d to another set of Doppler modulation frequencies used for adjacent sequences 241, 242; 243, 244; 245, 246; 247, 248 of the radar signal ramp r for transmitter antenna arrangements 210a, 210b, 210c, 210d.
[0033] Now refer to Figures 4A to 4C and Figures 5A to 5C The practical technical effects achieved using this disclosure are discussed, and the accompanying figures illustrate the spectral amplitude as a function of the Doppler frequency or Doppler spectral bin.
[0034] Figures 4A to 4C The disclosure includes the first sequence 241, the third sequence 243, the fifth sequence 245, and the seventh sequence 247 of the radar signal ramp r for detecting radar signals. Figure 1 and Figure 2 The case shown is of two separate target objects 140 and 141, in which these sequences 241, 243, 245, and 247 of the radar signal ramp r are transmitted more or less simultaneously.
[0035] exist Figure 4AIn the diagram, the first target object 140 actually existing in Doppler chamber 5 is indicated by dashed line 440, and the corresponding received detections 401, 402, 403, and 404 are indicated by solid lines. The first received detection 401, approximately at Doppler chamber 15, corresponds to the first sequence 241 of radar signal ramp r, and the second received detection 402, approximately at Doppler chamber 20, corresponds to the third sequence 243 of radar signal ramp r. Furthermore, the third received detection 403, approximately at Doppler chamber 25, corresponds to the fifth sequence 245 of radar signal ramp r, and the fourth received detection 404, approximately at Doppler chamber 45, corresponds to the seventh sequence 247 of radar signal ramp r.
[0036] exist Figure 4B In the diagram, the second target object 141 actually present in Doppler chamber 10 is indicated by dashed line 441, and the corresponding received detections 405, 406, 407, and 408 are indicated by solid lines. The fifth received detection 405, approximately at Doppler chamber 20, corresponds to the first sequence 241 of radar signal ramp r, and the sixth received detection 406, approximately at Doppler chamber 25, corresponds to the third sequence 243 of radar signal ramp r. Furthermore, the seventh received detection 407, approximately at Doppler chamber 30, corresponds to the fifth sequence 245 of radar signal ramp r, and the eighth received detection 408, approximately at Doppler chamber 50, corresponds to the seventh sequence 247 of radar signal ramp r.
[0037] exist Figure 4C In the diagram, the received detections of two target objects 140 and 141 are shown for the first sequence 241, the third sequence 243, the fifth sequence 245, and the seventh sequence 247 of the radar signal ramp r.
[0038] According to some aspects, the vehicle radar system 101 is adapted for DDMA (Doppler Division Multiple Access), which applies an artificial Doppler frequency to each transmitted signal. Because the transmitters do not use the same modulated artificial Doppler frequency, each transmitter antenna arrangement is found to be located at a different position in the Doppler spectrum. DDMA requires that the modulated Doppler frequency be known for the detected signal in the Doppler spectrum for a given transmitter antenna arrangement.
[0039] The above are typical results of such radar systems according to the prior art. Here, two detections of target object 141 collide at more or less the same Doppler chamber, making them indistinguishable from each other. When there are two or more target objects that are not resolved by range FFT and have different relative velocities and therefore different Doppler frequencies, an artificial Doppler modulated transmission signal of one target object may collide with an artificial Doppler modulated transmission signal of another target object. If this occurs, a subset of the received signal is contaminated by the signal of the other object, thus introducing errors into subsequent processing steps (e.g., bearing processing).
[0040] More specifically, in this example, the second received detection 402 associated with the first target object 441 and the fifth received detection 405 associated with the second target object 441 overlap at the same Doppler chamber, to the point that the two detections 402 and 405 are indistinguishable from each other. Similarly, the third received detection 403 associated with the first target object 441 and the sixth received detection 406 associated with the second target object 441 also overlap.
[0041] Figures 5A to 5C The disclosure includes the second sequence 242, the fourth sequence 244, the sixth sequence 246, and the eighth sequence 248 of the radar signal ramp r for detecting radar signal ramp r. Figure 1 and Figure 2 The case shown is of two separate target objects 140 and 141, in which these sequences 242, 244, 246, and 248 of the radar signal ramp r are transmitted more or less simultaneously.
[0042] For all these sequences 242, 244, 246, 248 of the radar signal ramp r, the phase increments Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8 from one ramp r to the next have been changed, as described above. This will result in the distribution of possible coincidence detections, as will be derived below. According to some aspects, the phase shift increments change during pauses in ramp r that do not transmit.
[0043] exist Figure 5AIn the diagram, the first target object 140 actually existing in Doppler chamber 5 is indicated by dashed line 440, and the corresponding received detections 501, 502, 503, and 504 are indicated by solid lines. The first received detection 501, approximately at Doppler chamber 9, corresponds to the second sequence 242 of radar signal ramp r, and the second received detection 502, approximately at Doppler chamber 22, corresponds to the fourth sequence 244 of radar signal ramp r. Furthermore, the third received detection 503, approximately at Doppler chamber 34, corresponds to the sixth sequence 246 of radar signal ramp r, and the fourth received detection 504, approximately at Doppler chamber 59, corresponds to the eighth sequence 248 of radar signal ramp r.
[0044] exist Figure 5B In the diagram, the second target object 141 actually existing in Doppler chamber 10 is indicated by dashed line 441, and the corresponding received detections 505, 506, 507, and 508 are indicated by solid lines. The fifth received detection 505, approximately at Doppler chamber 0, corresponds to the second sequence 242 of radar signal ramp r, and the sixth received detection 506, approximately at Doppler chamber 14, corresponds to the fourth sequence 244 of radar signal ramp r. Furthermore, the seventh received detection 407, approximately at Doppler chamber 28, corresponds to the sixth sequence 246 of radar signal ramp r, and the eighth received detection 508, approximately at Doppler chamber 40, corresponds to the eighth sequence 248 of radar signal ramp r.
[0045] exist Figure 5C In the diagram, for the second sequence 242, the fourth sequence 244, the sixth sequence 246, and the eighth sequence 248 of the radar signal ramp r, the received detections 501, 502, 503, 504, 505, 506, 507, and 508 of two target objects 140 and 141 are shown. Now, when the phase increment has been changed such that another artificial Doppler modulation is applied to each sequence 242, 244, 246, and 248 of the radar signal ramp r, there is no detection where they overlap to the extent that they are indistinguishable from each other at the same Doppler chamber.
[0046] For the next set of sequences of radar signal ramp r, the phase increment can be changed again, which means that although there will be cases where the detections overlap at the same Doppler chamber to the point that they cannot be distinguished from each other, the detection and overlap will be distributed over time, thus enabling more accurate detection of target objects 140, 141.
[0047] As mentioned above, this technique is particularly suitable for FDMM and can be used with well-known FDMM techniques to parse target objects 140 and 141.
[0048] Therefore, according to some aspects, such as Figure 6 As shown, the control unit 130 includes a digital signal processor (DSP) arrangement 632 adapted to process digital signals input from the receiver unit 212. According to some aspects, the control unit 130 is adapted to distinguish received signals associated with different detected target objects 140, 141 in the Doppler spectrum by finding signal patterns induced by artificial Doppler modulation.
[0049] This means that the well-known FDMM technique can be used to parse the target object.
[0050] According to some aspects, transmitter unit 208 includes signal generator 209 and phase shifter 215, wherein signal generator 209 is connected to phase shifter 215, which is in turn connected to transmitter antenna arrangements 210a, 210b, 210c, 210d, wherein phase shifter 215 is a programmable phase shifter 215 adapted to modulate artificial Doppler frequencies onto FMCW radar waveforms 204a, 204b, 204c, 204d.
[0051] This provides accurate and easily controllable phase shifts.
[0052] According to some aspects, receiver unit 212 is arranged to convert the mixed received signal 205 into a digital signal.
[0053] According to some aspects, the control unit 130 is adapted to control the signal generator 209, the phase shifter 215, and the receiver unit 212. This means that these devices are controlled in an efficient and centralized manner.
[0054] The techniques disclosed herein can be used with a single antenna system or in a system comprising one or more antenna arrays.
[0055] Using this disclosure, signal blockages can be distributed over time across different transmitter antenna arrangements 210a, 210b, 210c, 210d, so that these blockages can be minimized.
[0056] According to some aspects, the control unit 130 is adapted to control the phase shifter 215 such that each phase shift increment Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8 is changed randomly among adjacent transmission sequences 241, 242; 243, 244; 245, 246; 247, 248 of the radar signal ramp r. This facilitates distributed detection over time, thereby achieving more accurate detection of targets 140, 141.
[0057] Figure 6The components of a control unit 130 according to one embodiment are schematically illustrated in the form of multiple functional units. The processing circuitry 610 is provided using one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), dedicated hardware accelerator, etc., and is capable of executing software instructions stored in a computer program product, for example, in the form of storage medium 630. The processing circuitry 610 may further be provided as at least one application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA).
[0058] Specifically, the processing circuit 610 is configured to cause the control unit 130 to perform a set of operations or steps. These operations or steps have been discussed above in conjunction with various radar transceivers and methods. For example, the storage medium 630 may store the set of operations, and the processing circuit 610 may be configured to retrieve the set of operations from the storage medium 630 to cause the control unit 130 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuit 610 is thereby arranged to perform the methods and operations disclosed herein.
[0059] The storage medium 630 may also include a persistent storage device, which may be any single memory or combination thereof, such as magnetic memory, optical memory, solid-state memory, or even remotely mounted memory.
[0060] The control unit 130 may also include a communication interface 620 for communicating with at least one other unit. Therefore, the communication interface 620 may include one or more transmitters and receivers, including analog and digital components, and a suitable number of ports for wired or wireless communication.
[0061] The processing circuitry 610 is adapted to control the general operation of the control unit 130, for example, by sending data and control signals to external units and storage medium 630, by receiving data and reports from external units, and by retrieving data and instructions from storage medium 630. Other components and related functionalities of the control unit 130 are omitted so as not to obscure the concepts presented herein.
[0062] Figure 7 A computer program product 710 is shown, which includes computer-executable instructions 720 arranged on a computer-readable medium 730 to perform any of the methods disclosed herein.
[0063] refer to Figure 8This disclosure also relates to a method for a vehicle radar system 101. The method includes generating S100FMCW (Frequency Modulated Continuous Wave) radar waveforms 204a, 204b, 204c, 204d, wherein each radar waveform 204a, 204b, 204c, 204d includes at least two corresponding consecutive sequences 241, 242; 243, 244; 245, 246; 247, 248 of a radar signal ramp r, and feeding the corresponding radar waveform 204a, 204b, 204c, 204d to each of at least two transmitter antenna arrangements 204a, 210b, 210c, 204d. For each of at least two transmitter antenna arrangements 210a, 210b, 210c, 210d, the method includes transmitting adjacent sequences 241, 242; 243, 244; 245, 246; 247, 248 of the S300 radar signal ramp r, which have different phase shift increments Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8, such that artificial Doppler modulation is applied to each sequence 241, 242; 243, 244; 245, 246; 247, 248 of the radar signal ramp r.
[0064] Depending on some aspects, different phase angle increments Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8 are achieved by using a programmable phase shifter 215, which is adapted to modulate the artificial Doppler frequency onto the FMCW radar waveforms 204a, 204b, 204c, 204d.
[0065] According to some aspects, the method also includes receiving a signal 205 that has been reflected by one or more target objects 140, 141.
[0066] According to some aspects, the method also includes distinguishing received signals associated with different detected target objects 140, 141 in the Doppler spectrum by finding signal patterns caused by artificial Doppler modulation.
[0067] According to some aspects, the method also includes the application of DDMA, Doppler division multiple access.
[0068] This disclosure also relates to a vehicle 100 including a vehicle radar system 101 as described herein.
[0069] This disclosure is not limited to the provided examples, but can be freely modified within the scope of the appended claims. Any number of transmitter antenna arrangements 210a, 210b, 210c, 210d may exist, but at least two should exist. Any number of consecutive sequences 241, 242; 243, 244; 245, 246; 247, 248 of radar signal ramps r may exist within a radar cycle or radar signal block, but at least two should exist. Two or more radar signal blocks may exist within a radar cycle.
[0070] In this context, a radar cycle is an observation phase during which the vehicle radar system 101 is configured to acquire data, process the data at several signal processing levels, and transmit usable results. This can be a fixed time interval (e.g., 40 to 60 milliseconds), or it can be a dynamic time interval depending on environmental conditions and processing load.
[0071] The phase angle increment of the simultaneously transmitted FMCW waveform can be the same and / or vary for different sequences of radar signal ramps.
Claims
1. A vehicle radar system (101) comprising a control unit (130) and a transceiver unit (110), the transceiver unit further comprising a plurality of transmitter antenna arrangements (210a, 210b, 210c, 210d) and a transmitter unit (208) arranged to generate FMCW, frequency-modulated continuous wave radar waveforms (204a, 204b, 204c, 204d), wherein each radar waveform (204a, 204b, 204c, 204d) comprises at least two corresponding consecutive sequences (241, 242; 243, 244; 245, 246; 247, 248) of radar signal ramps (r), and wherein, The transmitter unit (208) is adapted to feed a corresponding radar waveform (204a, 204b, 204c, 204d) to each of at least two transmitter antenna arrangements (210a, 210b, 204c, 204d), characterized in that for each of the at least two transmitter antenna arrangements (210a, 210b, 210c, 210d), the transmitter unit (208) is adapted to generate adjacent sequences (241, 242; 243, 244; 245, 246; 247, 248) of radar signal ramps (r), the adjacent sequences having different phase shift increments (Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8), such that for each sequence (241, 242; 243, 244) of the radar signal ramps (r), the corresponding radar waveform (204a, 204b, 204c, 204d) is fed to the radar signal ramps (r). 244; 245, 246; 247, 248) Apply artificial Doppler modulation.
2. The vehicle radar system (101) according to claim 1, wherein, The transmitter unit (208) includes a signal generator (209) and a phase shifter (215), wherein the signal generator (209) is connected to the phase shifter (215), which is in turn connected to the transmitter antenna arrangement (210a, 210b, 210c, 210d), wherein the phase shifter (215) is a programmable phase shifter (215) adapted to modulate an artificial Doppler frequency onto the FMCW radar waveform (204a, 204b, 204c, 204d).
3. The vehicle radar system (101) according to any one of claims 1 or 2, wherein, The transceiver unit (110) further includes a receiver unit (212) and a plurality of receiver antenna arrangements (213a, 213b, 213c, 213d) adapted to receive signals (205) that have been reflected by one or more target objects (140, 141).
4. The vehicle radar system (101) according to claim 3, wherein, The control unit (130) includes a digital signal processor (DSP) arrangement (632) adapted to process digital signals input from the receiver unit (212).
5. The vehicle radar system (101) according to claim 4, wherein, The control unit (130) is adapted to distinguish received signals by finding signal patterns caused by the artificial Doppler modulation, the received signals being associated with different detected target objects (140, 141) in the Doppler spectrum.
6. The vehicle radar system (101) according to any one of claims 3 to 5, wherein, The receiver unit (212) is arranged to convert the mixed received signal (205) into a digital signal.
7. The vehicle radar system (101) according to any one of claims 3 to 6, wherein, The control unit (130) is adapted to control the signal generator (209), the phase shifter (215), and the receiver unit (212).
8. The vehicle radar system (101) according to any one of claims 3 to 7, wherein, The control unit (130) is adapted to control the phase shifter (215) such that each phase shift increment (Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8) is changed randomly between adjacent transmission sequences (241, 242; 243, 244; 245, 246; 247, 248) of the radar signal ramp (r).
9. The vehicle radar system (101) according to any one of the preceding claims, wherein, The vehicle radar system (101) is adapted for DDMA, Doppler division multiple access.
10. A method for a vehicle radar system (101), the method comprising: Generate (S100) FMCW, frequency-modulated continuous wave radar waveforms (204a, 204b, 204c, 204d), wherein each radar waveform (204a, 204b, 204c, 204d) includes at least two corresponding continuous sequences (241, 242; 243, 244; 245, 246; 247, 248) of the radar signal ramp (r); and Feed (S200) the corresponding radar waveform (204a, 204b, 204c, 204d) to each of at least two transmitter antenna arrangements (210a, 210b, 204c, 204d). Its features For each of the at least two transmitter antenna arrangements (210a, 210b, 210c, 210d), the method includes Transmit (S300) adjacent sequences (241, 242; 243, 244; 245, 246; 247, 248) of the radar signal ramp (r), the adjacent sequences having different phase shift increments (Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8) such that artificial Doppler modulation is applied to each sequence (241, 242; 243, 244; 245, 246; 247, 248) of the radar signal ramp (r).
11. The method according to claim 10, wherein, The different phase angle increments (Δω1, Δω2; Δω3, Δω4; Δω5, Δω6; Δω7, Δω8) are implemented by using a programmable phase shifter (215) adapted to modulate the artificial Doppler frequency onto the FMCW radar waveform (204a, 204b, 204c, 204d).
12. The method according to any one of claims 10 or 11, the method further comprising receiving a signal (205) that has been reflected by one or more target objects (140, 141).
13. The method of claim 12, further comprising distinguishing the received signal by finding a signal pattern caused by the artificial Doppler modulation, the received signal being associated with different detected target objects (140, 141) in the Doppler spectrum.
14. The method according to any one of claims 10 to 13, the method further comprising applying DDMA, Doppler division multiple access.
15. A vehicle (100) comprising a vehicle radar system (101) according to any one of claims 1 to 9.
Citation Information
Patent Citations
MIMO radar apparatus and wireless communication method using the same
US20110140949A1