Doppler phase difference compensation method, millimeter wave radar, product and vehicle

Abstract

The present application provides a Doppler phase difference compensation method, a millimeter wave radar, a product and a vehicle. The Doppler phase difference compensation method comprises: obtaining echo data corresponding to all Chirp waveform signals transmitted in time-sharing manner by multiple transmission channels within a frame period; wherein a single transmitted Chirp waveform signal is a DDMA_MIMO waveform, and the Chirp waveform signals corresponding to multiple transmission channels transmitted in time-sharing manner constitute a TDMA_MIMO waveform; performing distance-dimensional FFT processing on the echo data; performing demodulation processing on the DDMA_MIMO waveform to obtain separated channel data corresponding to each DDMA_MIMO waveform; based on the separated channel data corresponding to each DDMA_MIMO waveform, performing angle-dimensional FFT processing on all or part of the channel data inside each DDMA_MIMO waveform to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation; determining a Doppler compensation speed using the reference angle spectrum, and performing Doppler phase difference compensation on all DDMA_MIMO channels using the Doppler compensation speed.

Description

Technical Field

[0001] The present application relates to the field of radar technology, and in particular to a Doppler phase difference compensation method, a millimeter wave radar, a computer program product and a vehicle. Background Art

[0002] Millimeter-wave radar detects and tracks targets by emitting and receiving electromagnetic waves, and can simultaneously measure the distance, speed, and angle of the target. Compared with cameras and lidars, millimeter-wave radars have good environmental and weather adaptability, and can adapt to application scenarios such as strong light, night, heavy rain, fog, and dust. They have been widely used in vehicle-mounted ADAS (Advanced Driving Assistance System) assisted driving systems and vehicle-mounted AD (Autonomous Driving) automatic driving systems. Through the mutual integration of cameras, lidars, and millimeter-wave radars, the redundancy of intelligent decision-making can be improved, and the high reliability and safety of ADAS assisted driving or AD automatic driving can be achieved.

[0003] In order to minimize the cost of vehicle-mounted millimeter-wave radar while achieving better angular resolution, vehicle-mounted millimeter-wave radar generally uses MIMO (Multiple-Input Multiple-Output) working mode, using a relatively small number of actual antennas to virtualize more MIMO antennas, and using the number of MIMO virtual antennas to ensure angular resolution, and by using a relatively small number of actual antennas to ensure the cost of vehicle-mounted radar. Typically, if the number of transmitting antennas is M and the number of receiving antennas is N, the maximum number of MIMO antennas that can be virtualized is M*N. Assuming that the number of transmitting antennas is 4 and the number of receiving antennas is 4, the total number of actual antennas is 8, but 4*4=16 MIMO antennas can be virtualized, using fewer actual antennas to virtualize more MIMO antennas.

[0004] Common MIMO waveforms used in automotive millimeter-wave radars include TDMA (Time Division Multiple Access) time division MIMO and DDMA (Doppler Division Multiple Access) Doppler frequency division MIMO.

[0005] Among them, TDMA-MIMO realizes MIMO virtual channels by enabling the transmission channels in time-sharing, which is the optimal orthogonal waveform in theory. However, due to the delay in enabling each transmission channel, there is a Doppler phase difference caused by target motion between the signals of different transmission channels received by the same receiving channel. For TDMA-MIMO, the Doppler phase difference caused by target motion needs to be compensated before direction finding. In addition, it takes a long time for TDMA-MIMO to enable all transmission channels, which limits the improvement of the refresh rate of vehicle-mounted millimeter-wave radar data.

[0006] DDMA-MIMO enables the transmission channels at the same time. Based on the different Doppler frequency deviations corresponding to the different phase encoding values ​​of each transmission channel, the signals corresponding to each transmission channel are separated during the Doppler dimension FFT (Fast Fourier Transform) processing. For DDMA-MIMO, since each transmission channel transmits at the same time, there is no additional Doppler phase difference between the transmission channels. Doppler phase difference compensation is not required before direction finding. However, in order to ensure the performance of DDMA-MIMO when separating the transmission channels, the number of channels transmitting at the same time should not be too large.

[0007] For vehicle-mounted millimeter-wave radars with a small number of transmission channels, a single TDMA-MIMO waveform or a single DDMA-MIMO waveform can meet the requirements. However, for vehicle-mounted millimeter-wave radars with a large number of transmission channels, such as millimeter-wave imaging radars, a single TDMA-MIMO waveform or a single DDMA-MIMO waveform may not meet the use requirements. In this case, a composite waveform of TDMA-MIMO plus DDMA-MIMO may be required. In this case, the vehicle-mounted millimeter-wave radar needs to perform Doppler phase difference compensation before performing direction finding processing. Summary of the invention

[0008] In order to solve the existing technical problems, the present application provides a Doppler phase difference compensation method, a millimeter wave radar, a computer program product and a vehicle that can perform Doppler phase difference compensation before direction finding processing.

[0009] In a first aspect, a Doppler phase difference compensation method is provided, comprising:

[0010] Acquire echo data corresponding to all Chirp waveform signals transmitted in time-sharing manner by multiple transmission channels within a frame period; wherein a single transmitted Chirp waveform signal is a DDMA_MIMO waveform, and Chirp waveform signals corresponding to multiple transmission channels transmitted in time-sharing manner constitute a TDMA_MIMO waveform;

[0011] Performing distance-dimensional FFT processing on the echo data;

[0012] Demodulate the DDMA_MIMO waveform to obtain separate channel data corresponding to each DDMA_MIMO waveform;

[0013] Based on the separated channel data corresponding to each DDMA_MIMO waveform, all or part of the channel data within each DDMA_MIMO waveform are subjected to angle-dimensional FFT processing to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation;

[0014] The reference angle spectrum is used to determine a Doppler compensation speed, and Doppler phase difference compensation is performed on all DDMA_MIMO channels using the Doppler compensation speed.

[0015] In a second aspect, a vehicle-mounted millimeter-wave radar is provided, comprising a millimeter-wave radar processor and a memory, wherein the memory stores a computer program executable by the millimeter-wave radar processor;

[0016] When the computer program is executed by the millimeter wave radar processor, the Doppler phase difference compensation method described in any embodiment of the present application is implemented.

[0017] In a third aspect, a computer program product is provided, including a computer program, wherein when the computer program is executed by a processor, the Doppler phase difference compensation method described in any embodiment of the present application is implemented.

[0018] In a fourth aspect, a vehicle is provided, comprising an on-board assisted driving system, wherein the on-board assisted driving system comprises an on-board central control system and a data acquisition unit communicatively connected to the on-board central control system; the data acquisition unit comprises the millimeter-wave radar described in any embodiment of the present application; or, the data acquisition unit comprises a on-board radar, and the on-board radar is loaded with a computer program product provided in any embodiment of the present application.

[0019] The Doppler phase difference compensation method provided in the above embodiment enables multiple DDMA_MIMO waveforms in time division, and the multiple DDMA_MIMO waveforms constitute a TDMA_MIMO waveform. There is a Doppler phase difference between the channels of each DDMA_MIMO waveform, and the phase difference between the MIMO virtual antennas formed by the multiple transmitting antennas enabled at the same time is only related to the target angle, and has nothing to do with the target speed. By obtaining the separated channel data corresponding to each DDMA_MIMO waveform, the internal channel data of each DDMA_MIMO waveform is used to perform angle-dimensional FFT processing to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation. In this way, the unique correlation between the DDMA_MIMO waveform channel in the composite waveform and the TDMA_MIMO waveform channel after Doppler phase difference compensation is used to complete the Doppler phase difference compensation by determining the reference angle spectrum based on the DDMA_MIMO waveform channel, which is equivalent to realizing Doppler phase difference compensation by multiplexing the same transmitting unit in different DDMA_MIMO waveforms. It is not necessary to determine the accurate speed of the target, and the Doppler phase difference compensation can be completed within one frame period, thereby supporting the radar to output the target angle in a single frame.

[0020] The vehicle-mounted millimeter-wave radar, computer program product, and vehicle provided in the above embodiments belong to the same concept as the corresponding Doppler phase difference compensation method embodiments, and thus have the same technical effects as the corresponding Doppler phase difference compensation method embodiments, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 4 is a diagram of optional application scenarios of a Doppler phase difference compensation method in an embodiment.

[0022] Figure 2 Schematic diagram of the working principle of a vehicle-mounted millimeter-wave radar in one embodiment.

[0023] Figure 3 FIG. 4 is a flow chart of a Doppler phase difference compensation method in one embodiment.

[0024] Figure 4 FIG. 4 is a composite waveform diagram of a DDMA_MIMO waveform and a TDMA_MIMO waveform in an embodiment.

[0025] Figure 5 FIG. 4 is a flow chart of a Doppler phase difference compensation method in another embodiment.

[0026] Figure 6 The figure is an example diagram of a vehicle-mounted millimeter-wave radar antenna array in an optional specific example.

[0027] Figure 7 for Figure 6A schematic diagram of a MIMO virtual antenna array formed by the antenna array shown.

[0028] Figure 8 for Figure 6 The antenna array shown realizes Figure 7 The composite waveform diagram of the DDMA_MIMO waveform and the TDMA_MIMO waveform of the MIMO virtual antenna array is shown.

[0029] Fig. 9 FIG. 4 is a flowchart of a Doppler phase difference compensation method in an optional specific example.

[0030] Fig.10 It is a schematic diagram of an azimuth angle spectrum in an optional specific example.

[0031] Fig.11 The figure is a working flow chart of the vehicle-mounted millimeter wave radar in one embodiment.

[0032] Fig.12 Schematic diagram of the structure of a vehicle-mounted millimeter-wave radar in one embodiment. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0034] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0035] In the following description, the expression "some embodiments" is involved, which describes a subset of all possible embodiments. It should be noted that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

[0036] In the following description, the terms "first, second, third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first, second, third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0037] See also Figure 1 , which is an optional application scenario diagram of the Doppler phase difference compensation method provided by an embodiment of the present application applied to a vehicle. The vehicle-mounted millimeter wave radar 200 is usually installed on both sides of the front of the vehicle 100. The common installation position of the vehicle-mounted millimeter wave radar 200 is not limited to Figure 1The forward position shown also includes the front corner, rear corner and rear corner positions, which are used to detect and perceive the surrounding environment targets (target 1, target 2, target 3).

[0038] See also Figure 2 , is a schematic diagram of the structure of the vehicle-mounted millimeter-wave radar. The vehicle-mounted millimeter-wave radar mainly consists of four functional parts:

[0039] 1) Antenna array, which consists of a transmitting array and a receiving array. Automotive millimeter-wave radars generally adopt the MIMO (Multiple-Input Multiple-Output) working mode, and realize the antenna array required for direction finding through the MIMO working mode between the unit antennas of the transmitting array. Common MIMO implementation methods include TDMA (Time Division Multiple Access) time division MIMO and DDMA (Doppler Division Multiple Access) Doppler frequency division MIMO.

[0040] 2) MRTR (Millimeter-wave Radar Transceiver, millimeter-wave radar transceiver module or chip), millimeter-wave radar transceiver functional module, mainly composed of transmitting components, receiving components and linear frequency modulation local oscillator source components. MRTR generates and transmits the working waveform signal of the millimeter-wave radar, receives and discretely samples the reflected waveform signal of the target, and sends the sampled reflected waveform signal to the MRP (Millimeter-wave Radar Processor) millimeter-wave radar processor.

[0041] 3) MRP (Millimeter-wave Radar Processor), millimeter-wave radar processor, receives the reflected waveform signal from MRTR and performs digital processing to obtain information such as the distance, speed and angle of environmental targets, clusters, identifies and tracks targets, and outputs point cloud-level detection results or target-level detection results. From the main functional division, MRP is mainly composed of distance measurement module, speed measurement module, angle measurement module and target clustering identification and tracking module. The above modules can be implemented through embedded software, FPGA (Field Programmable Gate Array) or AISC (Application Specific Integrated Circuit) application-specific integrated circuits.

[0042] The Doppler phase difference compensation method provided in the embodiment of the present application is mainly implemented in the MRP speed measurement module. The implementation form, composition mode or module division mode of MRP does not affect the use of the Doppler phase difference compensation method provided in the embodiment of the present application.

[0043] 4) A read-write memory for storing the working data of the millimeter wave radar, including working parameter data and process data stored in advance, such as the structural size parameters of the antenna array and the threshold parameters required by the Doppler phase difference compensation method provided in the embodiment of the present application.

[0044] It should be noted that the configuration form or composition method of the functional parts of the above-mentioned vehicle-mounted millimeter-wave radar does not affect the use of the Doppler phase difference compensation method provided in the embodiment of the present application; in terms of application scenarios, the use of the Doppler phase difference compensation method provided in the embodiment of the present application can be applied to all applications that use electromagnetic waves for target direction finding, and is not limited to vehicle-mounted millimeter-wave radar applications.

[0045] See also Figure 3 , a Doppler phase difference compensation method provided in an embodiment of the present application comprises the following steps:

[0046] S101, obtaining echo data corresponding to all Chirp waveform signals transmitted in time-sharing manner by multiple transmission channels within a frame period; wherein a single transmitted Chirp waveform signal is a DDMA_MIMO waveform, and Chirp waveform signals corresponding to multiple transmission channels transmitted in time-sharing manner constitute a TDMA_MIMO waveform.

[0047] The frame period refers to the time required for the radar to transmit and receive data and to generate or transmit a frame. In the embodiment of the present application, the frame period represents the basic time unit of the radar system when processing data. The frame period is related to the performance parameters of the radar, including the maximum Doppler frequency, echo repetition frequency, range resolution, velocity resolution, etc.

[0048] TDMA_MIMO realizes MIMO virtual channels by enabling the transmission channel in time-sharing mode. It is the theoretically optimal orthogonal waveform, but it is affected by Doppler phase difference, and TDMA-MIMO has limitations on improving the data refresh rate of vehicle-mounted millimeter-wave radar.

[0049] DDMA-MIMO enables multiple transmit channels at the same time, and there is no influence of Doppler phase difference. However, the number of transmit channels enabled at the same time should not be too large to ensure the performance of DDMA-MIMO demodulation.

[0050] For vehicle-mounted millimeter-wave radars with a small number of transmission channels, a single TDMA-MIMO waveform or a single DDMA-MIMO waveform can meet the requirements. However, for vehicle-mounted millimeter-wave radars with a large number of transmission channels, such as millimeter-wave imaging radars, a single TDMA-MIMO waveform or a single DDMA-MIMO waveform may not meet the use requirements. In this case, a composite waveform of TDMA-MIMO plus DDMA-MIMO may be required. In the embodiment of the present application, a composite waveform of TDMA-MIMO composed of multiple DDMA-MIMO waveforms is transmitted through time-sharing enabled transmission channels, such as Figure 4 As shown, the waveform orthogonality, data refresh rate, and DDMA demodulation performance are taken into account. The echo data corresponding to all Chirp waveform signals transmitted by multiple transmission channels in a frame period are received by the receiving array, and multiple DDMA-MIMO waveforms are used for demodulation before the subsequent direction finding processing. The reference angle spectrum is determined by demodulation, and the Doppler phase difference compensation is performed using the reference angle spectrum.

[0051] S102, performing range-dimensional FFT processing on the echo data.

[0052] FFT (Discrete Fourier Transform) processing converts the time domain signal to the frequency domain through discrete Fourier processing. The distance dimension FFT processing of the echo data means that the millimeter wave radar transmits a linear frequency modulation pulse and receives the echo signal from the target, mixes the received echo signal with the transmitted signal, generates an intermediate frequency (IF) signal, performs FFT processing on the intermediate frequency signal, converts the time domain signal into a frequency domain signal, and determines the distance of the target object by analyzing the FFT results. Among them, the frequency of the intermediate frequency signal of the echo signal is usually proportional to the distance between the target and the radar1, and the peak position in the spectrum corresponds to the distance of the target.

[0053] S103, demodulating the DDMA_MIMO waveform to obtain separated channel data corresponding to each DDMA_MIMO waveform.

[0054] The number of transmitting antennas simultaneously enabled in each DDMA_MIMO waveform is 2 or more. The number of transmitting antennas simultaneously enabled in DDMA_MIMO does not affect the adaptability of the Doppler phase difference compensation method of the embodiment of the present application. However, it should be noted that the more antennas simultaneously enabled in DDMA_MIMO, the worse the performance of DDMA_MIMO demodulation will be. In the Doppler phase difference compensation method of the embodiment of the present application, attention is not paid to the improvement of the demodulation method of DDMA_MIMO, and the known DDMA_MIMO demodulation method can be used to ensure that the correct demodulation result of DDMA_MIMO is obtained.

[0055] S104, based on the separated channel data corresponding to each DDMA_MIMO waveform, perform angle-dimensional FFT processing on all or part of the channel data within each DDMA_MIMO waveform to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation.

[0056] The separated channel data is obtained by demodulating each DDMA_MIMO waveform, and the unique correlation between the DDMA_MIMO waveform channel and the TDMA_MIMO waveform channel after Doppler phase difference compensation is used, so that the reference angle spectrum for subsequent Doppler phase difference compensation of the TDMA_MIMO channel can be determined according to the angle spectrum of the channel data after the DDMA_MIMO waveform is separated. The unique correlation between the DDMA_MIMO waveform channel and the TDMA_MIMO waveform channel after Doppler phase difference compensation includes but is not limited to the following:

[0057] (1) Without considering the influence of errors, the MIMO array composed of the TDMA_MIMO waveform channel and the MIMO array composed of multiple DDMA_MIMO waveform channels have the same direction finding characteristics, the elevation direction finding results or the azimuth direction finding results are the same, and the angle spectrum of the compensated TDMA_MIMO waveform channel is the same as the angle spectrum of the DDMA_MIMO waveform channel used as a reference. In specific implementation, if the influence of errors is considered, a threshold condition can be set.

[0058] (2) Without considering the influence of errors, in the azimuth dimension direction finding or the elevation dimension direction finding direction, the MIMO array formed by the TDMA_MIMO waveform channel is a subset of the MIMO array formed by the DDMA_MIMO waveform channel, or the MIMO array formed by the DDMA_MIMO waveform channel is a subset of the MIMO array formed by the TDMA_MIMO waveform channel. At this time, the angular spectrum peak position of the compensated TDMA_MIMO waveform channel has a definite and unique relationship with the angular spectrum peak position of the DDMA_MIMO waveform channel. The specific peak position relationship can be obtained by the relative parameter relationship between the TDMA_MIMO waveform channel array and the DDMA_MIMO waveform channel array.

[0059] In the Doppler phase difference compensation method provided in the embodiment of the present application, when selecting the DDMA_MIMO waveform channel and the TDMA_MIMO waveform channel, the angle spectrum of at least one of the DDMA_MIMO waveform channels is made to have a unique correlation with the angle spectrum of the TDMA_MIMO waveform channel after Doppler phase difference compensation. By using the angle spectrum of the DDMA_MIMO waveform channel as a reference comparison feature and determining the reference angle spectrum, the Doppler phase compensation of the TDMA_MIMO waveform channel can be achieved, and unique and correct Doppler phase compensation can be achieved.

[0060] S105, determining a Doppler compensation speed by using the reference angle spectrum, and performing Doppler phase difference compensation on all DDMA_MIMO channels by using the Doppler compensation speed.

[0061] According to the unique correlation between the DDMA_MIMO waveform channel and the TDMA_MIMO waveform channel after Doppler phase difference compensation, the reference angle spectrum determined by the separated channel data obtained after demodulation processing based on each DDMA_MIMO waveform is used to calculate the Doppler compensation speed based on the reference angle spectrum. When performing Doppler phase difference compensation, it is not necessary to know the precise speed of the target, and direction finding can be completed within a single frame. The influence of distance-angle coupling and speed-angle coupling between multiple frames on the direction finding results can be avoided. For vehicle-mounted millimeter-wave radars with large-scale channels, the refresh rate can be guaranteed.

[0062] The Doppler phase difference compensation method provided in the above embodiment enables multiple DDMA_MIMO waveforms in time division, and the multiple DDMA_MIMO waveforms constitute a TDMA_MIMO waveform. There is a Doppler phase difference between the channels of each DDMA_MIMO waveform, and the phase difference between the MIMO virtual antennas formed by the multiple transmitting antennas enabled at the same time is only related to the target angle, and has nothing to do with the target speed. By obtaining the separated channel data corresponding to each DDMA_MIMO waveform, the internal channel data of each DDMA_MIMO waveform is used to perform angle-dimensional FFT processing to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation. In this way, the unique correlation between the DDMA_MIMO waveform channel in the composite waveform and the TDMA_MIMO waveform channel after Doppler phase difference compensation is used to complete the Doppler phase difference compensation by determining the reference angle spectrum based on the DDMA_MIMO waveform channel, which is equivalent to realizing Doppler phase difference compensation by multiplexing the same transmitting unit in different DDMA_MIMO waveforms. It is not necessary to determine the accurate speed of the target, and the Doppler phase difference compensation can be completed within one frame period, thereby supporting the radar to output the target angle in a single frame.

[0063] In some embodiments, see Figure 5 , step S105, comprising:

[0064] S1051, based on the target ambiguous speed determined by demodulating the DDMA_MIMO waveform, the maximum unambiguous speed, the preset speed ambiguity and the maximum speed measurement range determined according to the waveform parameters of each DDMA_MIMO waveform, determine the optional assumed speeds for Doppler phase difference compensation corresponding to different preset speed ambiguities.

[0065] S1052, performing Doppler phase difference compensation on multiple groups of TDMA_MIMO channels in the TDMA_MIMO waveform respectively through each of the optional assumed speeds; wherein each group of TDMA_MIMO channels includes channels in two adjacent DDMA_MIMO waveforms transmitted in time division.

[0066] S1053, performing angle-dimensional FFT processing on each group of TDMA_MIMO channels after Doppler phase difference compensation, to obtain azimuth angle spectra of each group of TDMA_MIMO channels under each of the optional assumed speeds.

[0067] S1054, according to the correlation between the azimuth angle spectrum of each group of TDMA_MIMO channels at each of the optional assumed speeds and the reference angle spectrum, select the optional assumed speed corresponding to the angle spectrum data whose correlation meets the preset threshold condition, and determine the Doppler compensation speed.

[0068] S1055: Perform Doppler phase difference compensation on all DDMA_MIMO channels based on the Doppler compensation speed.

[0069] In the embodiment of the present application, the millimeter wave radar processes the echo data received within a frame period to implement the Doppler phase difference compensation method, which is mainly executed by the MRP chip (millimeter wave radar processor), while the transmission of a TDMA-MIMO composite waveform composed of multiple DDMA-MIMO waveforms through the time-sharing enabling transmission channel is mainly executed by the MRTR chip (millimeter wave radar chip).

[0070] All Chirp waveforms within a frame period are transmitted through the MRTR chip. The transmitted detection waveforms include DDMA_MIMO waveforms and TDMA_MIMO waveforms. A single transmitted Chirp waveform contains a DDMA_MIMO waveform. If the number of transmission channels enabled at the same time is 2 or more, a TDMA_MIMO waveform is formed between 2 or more DDMA_MIMO waveforms transmitted in time division.

[0071] The receiving channel of the MRTR chip receives all echo data reflected by the target and transmits all echo data within a frame period to the MRP chip.

[0072] The MRP chip performs distance-dimensional FFT processing on the echo data of each Chirp waveform of all receiving channels; then demodulates the DDMA_MIMO waveform to obtain the separated channel data and target fuzzy speed corresponding to each DDMA_MIMO waveform; based on the separated channel data corresponding to each DDMA_MIMO waveform, performs angle-dimensional FFT processing on all or part of the channels within each DDMA_MIMO waveform to generate a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation. Figure 8 Taking the composite waveform of TDMA-MIMO composed of four DDMA-MIMO waveforms as an example, the four DDMA-MIMO waveforms are demodulated respectively to obtain separated channel data corresponding to the four DDMA_MIMO waveforms, and angle-dimensional FFT processing is performed on all or part of the channels of each DDMA_MIMO waveform to obtain the corresponding angle spectrum, and a reference angle spectrum is generated based on multiple angle spectra.

[0073] Without considering errors, the angle spectra obtained after the four DDMA_MIMO waveforms are processed are the same. In some embodiments, the DDMA_MIMO waveform is demodulated to determine the reference angle spectrum, which also includes selecting only one of the DDMA_MIMO waveforms for demodulation to obtain its separated channel data, performing angle-dimensional FFT processing based on all or part of the channels of the DDMA_MIMO waveform, and obtaining the corresponding angle spectrum as the reference angle spectrum.

[0074] Based on the ambiguous speed obtained by DDMA_MIMO waveform demodulation, the maximum unambiguous speed of each DDMA_MIMO waveform is calculated according to the waveform parameters of each DDMA_MIMO waveform. According to the maximum speed measurement range of the vehicle-mounted radar, different speed ambiguities are assumed to obtain multiple possible assumed speeds of the target, that is, optional assumed speeds with Doppler phase difference compensation corresponding to different preset speed ambiguities.

[0075] The Doppler phase difference compensation is performed on the TDMA_MIMO channels one by one using optional assumed speeds, and the angle-dimensional FFT processing is performed on the TDMA_MIMO channels after compensation with different assumed speeds to obtain the angle spectra of the TDMA_MIMO channels after compensation with different assumed speeds; the correlation between the angle spectra of the TDMA_MIMO channels after compensation with different optional assumed speeds and the reference angle spectrum determined by the DDMA_MIMO channels is calculated; the optional assumed speed with the largest angle spectrum correlation and the angle spectrum correlation satisfying a predetermined threshold condition is selected as the Doppler compensation speed for Doppler phase difference compensation; the Doppler compensation speed is applied to all TDMA_MIMO channels to compensate for the Doppler phase difference of all TDMA_MIMO channels.

[0076] In the above embodiment, the Doppler phase compensation of the TDMA_MIMO waveform channel is achieved by using the correlation between the angle spectrum of the DDMA_MIMO waveform channel and the angle spectrum of the TDMA_MIMO waveform channel after Doppler phase difference compensation, and taking the angle spectrum of the DDMA_MIMO waveform channel as a reference comparison feature.

[0077] In some embodiments, step S1054 includes:

[0078] Compare the azimuth angle spectrum of each group of TDMA_MIMO channels under each of the optional assumed speeds with the reference angle spectrum, and select the optional assumed speed in each group of TDMA_MIMO channels whose azimuth angle spectrum is the same as or has the greatest correlation with the reference angle spectrum and satisfies a preset threshold condition as a candidate compensation speed;

[0079] Determining whether the selected compensation speeds are equal;

[0080] If they are not equal, the data in the current frame period is considered invalid;

[0081] If they are equal, the to-be-selected compensation speed is used as the Doppler compensation speed.

[0082] Since multiple DDMA_MIMO waveforms are enabled in time division, multiple DDMA_MIMO waveforms constitute a TDMA_MIMO waveform, and there is a time delay between different DDMA_MIMO waveforms, so there is a Doppler phase difference between different DDMA_MIMO waveform channels. After DDMA_MIMO is correctly demodulated, one or more waveform channels separated in two adjacent DDMA_MIMO waveforms form a group of TDMA_MIMO channels. According to the correlation between the azimuth angle spectrum of each group of TDMA_MIMO channels after Doppler phase compensation and the reference angle spectrum, the candidate compensation speeds for Doppler phase compensation can be obtained respectively. By judging whether the candidate compensation speeds are equal, the Doppler compensation speed corresponding to the failure of Doppler phase difference compensation or the success of Doppler phase difference compensation can be confirmed.

[0083] In some embodiments, the Doppler phase difference compensation method further includes:

[0084] Based on the waveform parameters of each DDMA_MIMO waveform, the maximum unambiguous speed is determined according to the following formula 1:

[0085]

[0086] Where c refers to the speed of light, f refers to the signal frequency, and T refers to the DDMA_MIMO waveform period.

[0087] The maximum unambiguous speed after demodulation of each DDMA_MIMO is related to the main signal frequency, the number of DDMA_MIMO waveforms contained in a TDMA_MIMO waveform and the delay between different DDMA_MIMO waveforms.

[0088] In some embodiments, in step S1051, the optional hypothetical speeds for Doppler phase difference compensation corresponding to different preset speed ambiguities are determined using the following formula 2:

[0089]

[0090] Wherein, V refers to the target blur speed;

[0091] V k It refers to the optional assumed velocity for Doppler phase difference compensation;

[0092] V max It refers to the maximum unambiguous speed of the DDMA_MIMO waveform, which can be obtained through the DDMA_MIMO waveform parameters;

[0093] k refers to the velocity ambiguity;

[0094] V r- It refers to the maximum speed measurement range in the negative direction;

[0095] V r+ Refers to the maximum speed measurement range in the positive direction.

[0096] By demodulating the DDMA_MIMO waveform, the separated channel data and target fuzzy speed corresponding to each DDMA_MIMO waveform are obtained. Based on the fuzzy speed V obtained by demodulating the DDMA_MIMO waveform, the maximum unambiguous speed V of each DDMA_MIMO waveform is calculated according to the waveform parameters of each DDMA_MIMO waveform. max 、The maximum speed measurement range of vehicle-mounted radar V r- ~V r+ , different preset speed ambiguities k, calculate and obtain multiple possible optional hypothesized speeds of the target.

[0097] In some embodiments, step S104 includes:

[0098] Based on the separated channel data corresponding to each DDMA_MIMO waveform, all or part of the channel data within each DDMA_MIMO waveform are subjected to angle-dimensional FFT processing to obtain the azimuth-dimensional angle spectrum corresponding to each DDMA_MIMO waveform;

[0099] The plurality of azimuth angle spectra are non-coherently accumulated to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation.

[0100] For multiple DDMA_MIMO waveforms, the azimuth angle spectrum of the MIMO virtual array formed by the separated channel data obtained after demodulation, if the error effect is not considered, the multiple azimuth angle spectra are exactly the same, which is used as the reference feature of the Doppler phase difference compensation of the TDMA_MIMO waveform channel. In practical applications, considering the effect of errors, the accuracy of the reference angle spectrum can be improved by performing non-coherent accumulation and taking the average value of multiple azimuth angle spectra.

[0101] Optionally, in step S104, based on the separated channel data corresponding to each DDMA_MIMO waveform, all or part of the channel data within each DDMA_MIMO waveform is subjected to angle-dimensional FFT processing to obtain azimuth-dimensional angle spectra corresponding to each DDMA_MIMO waveform, including:

[0102] Based on the separated channel data T1, T2 and T7 corresponding to the first DDMA_MIMO waveform, a first MIMO virtual array formed by the channel data T1, T2 and T7 is obtained; based on the separated channel data T3, T8 and T9 corresponding to the second DDMA_MIMO waveform, a second MIMO virtual array formed by the channel data T3, T8 and T9 is obtained; based on the separated channel data T4, T5 and T10 corresponding to the third DDMA_MIMO waveform, a third MIMO virtual array formed by the channel data T4, T5 and T10 is obtained; based on the separated channel data T6, T11 and T12 corresponding to the fourth DDMA_MIMO waveform, a fourth MIMO virtual array formed by the channel data T6, T11 and T12 is obtained;

[0103] The MIMO virtual arrays composed of channel data T1 and T7, T3 and T9, T4 and T10, T6 and T12 are respectively subjected to angle-dimensional FFT processing in the azimuth dimension to obtain azimuth-dimensional angle spectra corresponding to the first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform, respectively.

[0104] For ease of understanding, Figure 8 As shown, in the composite waveform of DDMA_MIMO plus TDMA_MIMO, the first DDMA_MIMO waveform is DDMA_MIMO_1, the second DDMA_MIMO waveform is DDMA_MIMO_2, the third DDMA_MIMO waveform is DDMA_MIMO_3, and the fourth DDMA_MIMO waveform is DDMA_MIMO_4 as an example for description.

[0105] like Figures 6 to 8 As shown, Figure 6It is a typical example of a vehicle-mounted millimeter-wave radar antenna array. Figure 7 for Figure 6 The antenna array shown constitutes a MIMO virtual antenna array. Figure 6 The antenna array shown can be realized through various MIMO waveform methods Figure 8 MIMO virtual array shown. Figure 8 In the MIMO virtual array shown, a total of 512 Chirp waveforms are included in one frame period, and the DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3 and DDMA_MIMO_4 waveforms each including 128 Chirp waveforms transmitted in time-sharing form a TDMA_MIMO.

[0106] DDMA_MIMO_1 enables T1, T2, and T7 transmissions at the same time, DDMA_MIMO_2 enables T3, T8, and T9 transmissions at the same time, DDMA_MIMO_3 enables T4, T5, and T10 transmissions at the same time, and DDMA_MIMO_4 enables T6, T11, and T12 transmissions at the same time. The transmitting antennas enabled at the same time within each DDMA_MIMO waveform are not affected by the Doppler phase difference. Since DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3, and DDMA_MIMO_4 are enabled in time division, each DDMA_MIMO waveform forms TDMA_MIMO, and there is an additional Doppler phase difference between each DDMA_MIMO waveform channel.

[0107] Typically, T1, T2 and T7 are enabled by DDMA_MIMO_1 at the same time, and the phase difference between the MIMO virtual antennas (first MIMO virtual array) formed by T1, T2 and T7 is only related to the target angle and has nothing to do with the target speed; T3, T8 and T9 are enabled by DDMA_MIMO_2 at the same time, and the phase difference between the MIMO virtual antennas (second MIMO virtual array) formed by T3, T8 and T9 is only related to the target angle and has nothing to do with the target speed; however, since DDMA_MIMO_2 has a delay relative to DDMA_MIMO_1, the phase difference between the MIMO virtual antenna formed by T3, T8 and T9 and the MIMO virtual antenna formed by T1, T2 and T7 is not only related to the target angle, but also has a Doppler phase difference related to the target speed. Similarly, there are MIMO virtual antennas (third MIMO virtual array) formed by T4, T5 and T10 enabled by DDMA_MIMO_3, and MIMO virtual antennas (fourth MIMO virtual array) formed by T6, T11 and T12 enabled by DDMA_MIMO_3, which are not described here.

[0108] like Figure 8The DDMA_MIMO plus TDMA_MIMO composite waveform shown, after DDMA is correctly demodulated, angle-dimensional FFT processing is performed on part of the channel data in each DDMA_MIMO waveform to obtain the corresponding azimuth-dimensional angle spectrum, namely, the azimuth-dimensional angle spectrum of the MIMO virtual array formed by T1 and T7 in each DDMA_MIMO_1 waveform, the azimuth-dimensional angle spectrum of the MIMO virtual array formed by T3 and T9 in the DDMA_MIMO_2 waveform, the azimuth-dimensional angle spectrum of the MIMO virtual array formed by T4 and T10 in the DDMA_MIMO_3 waveform, and the azimuth-dimensional angle spectrum of the MIMO virtual array formed by T6 and T12 in the DDMA_MIMO_4 waveform, which are the azimuth-dimensional angle spectra corresponding to the first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform, respectively.

[0109] Optionally, the Doppler phase difference compensation method further includes:

[0110] All Chirp waveform signals within a frame period are transmitted through a transmitting antenna according to a preset MIMO waveform; the preset MIMO waveform includes a first DDMA_MIMO waveform, a second DDMA_MIMO waveform, a third DDMA_MIMO waveform and a fourth DDMA_MIMO waveform transmitted in time, the first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform respectively include the same number of Chirp waveforms, and the first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform constitute a TDMA_MIMO waveform.

[0111] In this embodiment, taking the composite waveform of the TDMA_MIMO waveform composed of four DDMA_MIMO waveforms as an example, all Chirp waveforms within a processing frame period are transmitted through the MRTR chip, and the interior of a single transmitted Chirp waveform is a DDMA_MIMO waveform. The number of transmission channels enabled at the same time is 2 or more, and a TDMA_MIMO waveform is formed between two or more DDMA_MIMO waveforms transmitted in a time-sharing manner.

[0112] In order to have a more comprehensive understanding of the Doppler phase difference compensation method provided in the embodiment of the present application, please refer to Figure 2 , Figures 6 to 8 ,by Figure 2 Taking the structure of the vehicle-mounted millimeter-wave radar shown in the figure as an example, the main working process of the vehicle-mounted millimeter-wave radar and the process of the Doppler phase difference compensation method are explained.

[0113] like Figure 8 As shown, the composite waveform of DDMA_MIMO plus TDMA_MIMO, specifically taking four DDMA_MIMO waveforms forming a TDMA_MIMO waveform as an example.

[0114] The delay between DDMA_MIMO_1 and DDMA_MIMO_2 is T12, the delay between DDMA_MIMO_2 and DDMA_MIMO_3 is T23, the delay between DDMA_MIMO_3 and DDMA_MIMO_4 is T34, and the delay between DDMA_MIMO_4 and DDMA_MIMO_1 is T41. The delays T12, T23, T34, and T41 mentioned above may be equal or different.

[0115] The number of transmitting antennas simultaneously enabled within each DDMA_MIMO waveform is 2 or more, wherein the number of antennas simultaneously enabled within the DDMA_MIMO waveform does not affect the adaptability of the Doppler phase difference compensation method provided in the embodiment of the present application.

[0116] like Fig. 9 As shown, the Doppler phase difference compensation method includes:

[0117] S11, all Chirp waveforms within a frame period are transmitted through the MRTR chip, and the transmitted detection waveforms include DDMA_MIMO waveforms and TDMA_MIMO waveforms.

[0118] The internal part of a single transmitted Chirp waveform is a DDMA_MIMO waveform, and the number of simultaneously enabled transmission channels is 2 or more, and a TDMA_MIMO waveform is formed between 2 or more time-sharing transmitted DDMA_MIMO waveforms. When selecting a DDMA_MIMO waveform channel and a TDMA_MIMO waveform channel, by ensuring that the angle spectrum of at least one DDMA_MIMO waveform channel has a unique correlation with the angle spectrum of the TDMA_MIMO waveform channel after Doppler phase difference compensation, and by using the angle spectrum of the DDMA_MIMO waveform channel as a reference comparison feature, the Doppler phase compensation of the TDMA_MIMO waveform channel is achieved, and the Doppler phase compensation is unique and correct.

[0119] Figure 8 The DDMA_MIMO plus TDMA_MIMO composite waveform shown can be used Figure 6 The antenna array shown realizes Figure 7The MIMO virtual array implementation shown in the figure, such as: a single TDMA_MIMO waveform, only one transmitting antenna is enabled at the same time, and 12 transmitting antennas need to be transmitted in turn, which takes a long time, has a low data refresh rate, and is difficult to expand the speed measurement range; a single DDMA_MIMO waveform can enable all 12 transmitting antennas at the same time, which takes a short time and has a high data refresh rate, but the DDMA demodulation is difficult and it is difficult to obtain accurate separated channel data, especially in the case of multiple targets; and the composite waveform of the DDMA_MIMO waveform plus the TDMA_MIMO waveform takes into account waveform orthogonality, data refresh rate, DDMA demodulation and other performance.

[0120] Figure 8 An example of a DDMA_MIMO plus TDMA_MIMO composite waveform is shown, including the following features:

[0121] DDMA_MIMO_1 enables T1, T2 and T7 transmissions simultaneously, DDMA_MIMO_2 enables T3, T8 and T9 transmissions simultaneously, DDMA_MIMO_3 enables T4, T5 and T10 transmissions simultaneously, and DDMA_MIMO_4 enables T6, T11 and T12 transmissions simultaneously;

[0122] There is no Doppler phase difference effect on the transmitting antennas enabled simultaneously within each DDMA_MIMO waveform;

[0123] Since DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3 and DDMA_MIMO_4 are enabled in time division, TDMA_MIMO is formed between each DDMA_MIMO waveform, and there is an additional Doppler phase difference between each DDMA_MIMO waveform channel;

[0124] T1, T2 and T7 are enabled by DDMA_MIMO_1 at the same time, and the phase difference between the MIMO virtual antennas formed by T1, T2 and T7 is only related to the target angle, but not to the target speed; T3, T8 and T9 are enabled by DDMA_MIMO_2 at the same time, and the phase difference between the MIMO virtual antennas formed by T3, T8 and T9 is only related to the target angle, but not to the target speed; since DDMA_MIMO_2 has a delay relative to DDMA_MIMO_1, the phase difference between the MIMO virtual antenna formed by T3, T8 and T9 and the MIMO virtual antenna formed by T1, T2 and T7 is not only related to the target angle, but also has a Doppler phase difference related to the target speed.

[0125] S12, receiving all echo data reflected by the target through the receiving channel of the MRTR chip, and transmitting all echo data within a frame period to the MRP chip.

[0126] S13, the MRP chip performs distance dimension FFT processing on the echo data of each Chirp waveform of all receiving channels.

[0127] S14, the MRP chip demodulates the DDMA_MIMO waveform to obtain separated channel data and target fuzzy speed corresponding to each DDMA_MIMO waveform.

[0128] S15, based on the separated channel data corresponding to each DDMA_MIMO waveform, perform angle-dimensional FFT processing on all or part of the channels within each DDMA_MIMO waveform to generate a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation.

[0129] like Figure 8 The DDMA_MIMO plus TDMA_MIMO composite waveform shown in the figure, after DDMA is correctly demodulated, the azimuth angle spectrum of the MIMO virtual array formed by T1 and T7 in the DDMA_MIMO_1 waveform, the azimuth angle spectrum of the MIMO virtual array formed by T3 and T9 in the DDMA_MIMO_2 waveform, the azimuth angle spectrum of the MIMO virtual array formed by T4 and T10 in the DDMA_MIMO_3 waveform, and the azimuth angle spectrum of the MIMO virtual array formed by T6 and T12 in the DDMA_MIMO_4 waveform, if the error effect is not considered, the above four azimuth angle spectra are exactly the same, and are selected as reference features for TDMA_MIMO channel Doppler phase difference compensation, that is, as reference angle spectra; in actual implementation, considering the effect of errors, in order to improve the accuracy of the reference angle spectrum, the above four angle spectra are non-coherently accumulated and averaged as the reference angle spectrum.

[0130] S16, based on the ambiguous speed obtained by DDMA_MIMO waveform demodulation, the maximum unambiguous speed of each DDMA_MIMO waveform is calculated according to the waveform parameters of each DDMA_MIMO waveform, and according to the maximum speed measurement range of the vehicle-mounted radar, different speed ambiguities are assumed to obtain multiple possible assumed speeds of the target.

[0131] S17, using all the assumed speeds to perform Doppler phase difference compensation on the TDMA_MIMO channels one by one.

[0132] The calculation of the Doppler phase difference compensation value is shown in the following formula 3:

[0133]

[0134] Assuming the speed V k The corresponding Doppler phase difference compensation value;

[0135] T: The delay between TDMA_MIMO composed of DDMA_MIMO, for Figure 4 As shown, the delay between DDMA_MIMO_1 and DDMA_MIMO_2 is T12, the delay between DDMA_MIMO_2 and DDMA_MIMO_3 is T23, the delay between DDMA_MIMO_3 and DDMA_MIMO_4 is T34, and the delay between DDMA_MIMO_4 and DDMA_MIMO_1 is T41;

[0136] λ: Transmitted signal wavelength.

[0137] S18, performing angle-dimensional FFT processing on the TDMA_MIMO channels after different assumed speed compensation to obtain angle spectra of the TDMA_MIMO channels after different assumed speed compensation.

[0138] against Figure 8 In the DDMA_MIMO plus TDMA_MIMO composite waveform shown, errors are not considered. T2 and T8 constitute TDMA_MIMO. After Doppler phase difference compensation, the azimuth angle spectrum of the MIMO virtual array formed by T2 and T8 is equal to the above reference angle spectrum. In actual implementation, considering the influence of errors, threshold conditions can be set. Similarly, T5 and T11 constitute TDMA_MIMO. After Doppler phase difference compensation, the azimuth angle spectrum of the MIMO virtual array formed by T5 and T11 is equal to the above reference angle spectrum.

[0139] S19, obtaining the correlation between the TDMA_MIMO channel angle spectrum and the DDMA_MIMO channel angle spectrum after different assumed speed compensations.

[0140] By comparing the correlation between the azimuth angle spectrum of the TDMA_MIMO virtual array composed of T2 and T8 and the reference angle spectrum, the target speed 1 for Doppler phase difference compensation can be obtained; by comparing the correlation between the azimuth angle spectrum of the TDMA_MIMO virtual array composed of T5 and T11 and the reference angle spectrum, the target speed 2 for Doppler phase difference compensation can be obtained.

[0141] S20, selecting a hypothesized velocity with the largest angle spectrum correlation and an angle spectrum correlation satisfying a pre-threshold condition for Doppler phase difference compensation.

[0142] S21, applying the assumed speed to all TDMA_MIMO channels, and performing Doppler phase difference compensation on all TDMA_MIMO channels.

[0143] If target speed 1 is equal to target speed 2, target speed 1 is used for subsequent full-array Doppler phase difference compensation. If target speed 1 is not equal to target speed 2, it is considered that Doppler phase difference compensation has failed and the data of this frame is invalid.

[0144] In an optional specific example, the MRTR chip is Fig. 9 The MIMO waveform shown transmits 512 Chirp waveforms within a processing frame period, the signal frequency is 76.5 GHz, and the number of Chirps for DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3, and DDMA_MIMO_4 is 128.

[0145] The delay between DDMA_MIMO_1 and DDMA_MIMO_2 is 20us, the delay between DDMA_MIMO_2 and DDMA_MIMO_3 is 22us, the delay between DDMA_MIMO_3 and DDMA_MIMO_4 is 25us, and the delay between DDMA_MIMO_4 and DDMA_MIMO_1 is 17us.

[0146] The Chirp period of DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3 and DDMA_MIMO_4 is 84us. Based on this, the maximum unambiguous speed calculated by formula 1 after demodulation of DDMA_MIMO_1, DDMA_MIMO_2, DDMA_MIMO_3 and DDMA_MIMO_4 is:

[0147]

[0148] c, the speed of light is 3*108m / s;

[0149] f, signal frequency is 76.5GHz;

[0150] T, DDMA_MIMO waveform period is 84us.

[0151] The Doppler phase difference compensation method comprises the following steps:

[0152] Step 1: The receiving channel of the MRTR chip receives all the chirp waveform echo data reflected by the target and transmits all the echo data within a processing frame period to the MRP chip.

[0153] Step 2: The MRP chip performs distance-dimensional FFT processing on the echo data of each Chirp waveform of all receiving channels.

[0154] Step 3: The MRP chip performs inter-Chirp DDMA demodulation processing on each range gate in the range-dimensional FFT result of each DDMA_MIMO waveform to obtain the MIMO virtual channel data and target fuzzy velocity V corresponding to each DDMA_MIMO waveform.

[0155] -11.7m / s≤V≤11.7m / s

[0156] V: Ambiguous velocity obtained by DDMA demodulation.

[0157] Step 4: By demodulating DDMA_MIMO_1, a MIMO virtual array formed by T1, T2 and T7 can be obtained; by demodulating DDMA_MIMO_2, a MIMO virtual array formed by T3, T8 and T9 can be obtained; by demodulating DDMA_MIMO_3, a MIMO virtual array formed by T4, T5 and T10 can be obtained; by demodulating DDMA_MIMO_4, a MIMO virtual array formed by T6, T11 and T12 can be obtained.

[0158] Step 5: Perform angle FFT processing on the MIMO virtual arrays composed of T1 and T7, T3 and T9, T4 and T10, and T6 and T12 in the azimuth dimension. Without considering the error, four completely identical angle spectra are obtained. Assuming the azimuth angle of the target is 5°, the obtained angle spectrum is as follows: Fig.10 shown.

[0159] Step 6: Fig.10 The angle spectrum shown is used as the first reference feature RSP1 for the first Doppler phase difference compensation.

[0160] It should be noted that, in practical applications, due to the existence of errors, the four angle spectra obtained in step 5 may be non-coherently accumulated and then averaged to serve as the first reference feature RSP1 for the first Doppler phase difference compensation.

[0161] Step 7: Assuming that the target's true speed is 15 m / s, the fuzzy speed obtained by DDMA demodulation is -8.4 m / s. The maximum positive speed measurement range of the radar is 60 m / s, the maximum negative speed measurement range is -60 m / s, and the aforementioned maximum unambiguous speed is 11.7 m / s. Then, the assumed target speed V for Doppler phase difference compensation is calculated by formula 2: k They are -55.2m / s, -31.8m / s, -8.4m / s, 15m / s, and 38.4m / s.

[0162]

[0163] Step 8: Use the above assumed target speeds of -55.2 m / s, -31.8 m / s, -8.4 m / s, 15 m / s, and 38.4 m / s to compensate for the Doppler phase difference of the virtual MIMO channel data corresponding to T8 relative to T2.

[0164] The Doppler phase difference compensation value calculated by formula 3 is:

[0165]

[0166] like Figure 8 As shown, T is 20us, and λ is the wavelength of 3.92cm corresponding to the signal frequency of 76.5GHz.

[0167] Step 9: Similarly, using the above-mentioned assumed target speeds of -55.2m / s, -31.8m / s, -8.4m / s, 15m / s, and 38.4m / s, compensate for the Doppler phase difference of the virtual MIMO channel data corresponding to T11 relative to T5;

[0168] The Doppler phase difference compensation value calculated by formula 3 is:

[0169]

[0170] like Figure 8 As shown, T is 25us, and λ is the wavelength of 3.92cm corresponding to the signal frequency of 76.5GHz.

[0171] Step 10: Combine the MIMO virtual array generated by T2 and the MIMO virtual array generated by T8 after Doppler phase difference compensation into a MIMO virtual array, and obtain the azimuth angle spectrum data SP28 of the combined MIMO virtual array under each assumed speed condition.

[0172] Step 11: Compare and analyze SP28 and RSP1, and select the assumed speed V28 that is the same as RSP1 (without considering the error) or the one with the greatest correlation between SP28 and RSP1 and meets the preset threshold condition (when the error is considered in actual application) as the subsequent Doppler phase difference compensation speed. For this example, V28 = 15 m / s.

[0173] Step 12: Combine the MIMO virtual array generated by T5 and the MIMO virtual array generated by T11 after Doppler phase difference compensation into a MIMO virtual array, and obtain the azimuth angle spectrum data SP511 of the combined MIMO virtual array under each assumed speed condition.

[0174] Step 13: Compare and analyze SP511 and RSP1, and select the assumed speed V511 that is the same as RSP1 (without considering the error) or has the greatest correlation with RSP1 and meets the preset threshold condition (when the error is considered in actual application) as the subsequent Doppler phase difference compensation speed. For this example, V511 = 15 m / s.

[0175] Step 14: Compare and analyze whether the speed V28 with the maximum correlation between SP28 and RSP1 is equal to the speed V511 with the maximum correlation between SP511 and RSP1; if they are equal, it is considered that the Doppler phase difference compensation is correct, and V28=V511 is taken as the subsequent Doppler compensation speed; if they are not equal, it is considered that the Doppler phase difference compensation has failed, the data of this frame is invalid, and no subsequent processing is performed.

[0176] Step 15: Use V28=V511 as the Doppler compensation speed to compensate for the Doppler phase difference between the DDMA_MIMO_2 virtual channel and the DDMA_MIMO_1 virtual channel.

[0177] The Doppler phase difference compensation value is:

[0178]

[0179] like Figure 8 As shown, T is 20us, and λ is the wavelength of 3.92cm corresponding to the signal frequency of 76.5GHz.

[0180] Step 16: Use V28=V511 as the Doppler compensation speed to compensate for the Doppler phase difference between the DDMA_MIMO_3 virtual channel and the DDMA_MIMO_1 virtual channel.

[0181] The Doppler phase difference compensation value is:

[0182]

[0183] like Figure 8 As shown, T is 42us, and λ is the wavelength of 3.92cm corresponding to the signal frequency of 76.5GHz.

[0184] Step 17: Use V28=V511 as the Doppler compensation speed to compensate for the Doppler phase difference between the DDMA_MIMO_4 virtual channel and the DDMA_MIMO_1 virtual channel.

[0185] The Doppler phase difference compensation value is:

[0186]

[0187] like Figure 8 As shown, T is 67us, and λ is the wavelength of 3.92cm corresponding to the signal frequency of 76.5GHz.

[0188] The Doppler phase difference compensation method provided in the embodiment of the present application is suitable for a vehicle-mounted millimeter-wave radar using a composite waveform of TDMA-MIMO plus DDMA-MIMO, especially for a vehicle-mounted millimeter-wave radar with a large-scale transmission channel. It does not need to solve the accurate speed of the target in advance, and can complete the Doppler phase difference compensation within one frame period, supporting the radar to output the target angle in a single frame, avoiding the speed-angle coupling and distance-angle coupling problems between multiple frames.

[0189] Among them, the typical workflow of the vehicle-mounted millimeter wave radar using the Doppler phase difference compensation method proposed in the embodiment of the present application is as follows: Fig.11 As shown, the following steps are included:

[0190] S211, the vehicle-mounted millimeter-wave radar is powered on and initialized, and the working parameters are read and sent down.

[0191] S212, the vehicle-mounted millimeter-wave radar receives an instruction to start working.

[0192] S213, the MRTR chip linear frequency modulation local oscillator source component generates a linear frequency modulation waveform local oscillator signal according to the waveform parameters, and transmits it to the transmitting component and the receiving component.

[0193] S214, the MRTR chip transmitting component generates a transmitting signal according to the linear frequency modulation waveform local oscillator signal, and radiates the transmitting signal through the transmitting antenna array.

[0194] S215, the receiving antenna array receives the waveform signal reflected by the target and transmits it to the MRTR chip receiving component.

[0195] S216, the MRTR chip performs discrete ADC sampling on the waveform signal reflected by the received target.

[0196] S217, the MRP chip ranging module performs ranging processing on the discrete ADC signal from the MRTR chip.

[0197] S218, the MRP chip speed measurement module performs speed measurement processing.

[0198] S219, the MRP chip angle measurement module performs angle measurement processing.

[0199] S220, the MRP chip target clustering association tracking module performs target-level data processing.

[0200] S221, the MRP chip outputs point cloud-level detection results or target-level detection results.

[0201] S222, completing scene target detection in a loop until a condition for stopping operation is met.

[0202] Among them, the Doppler phase difference compensation method based on the vehicle-mounted millimeter-wave radar proposed in the embodiment of the present application can be executed by the millimeter-wave radar chip, and can be specifically completed in step S218.

[0203] On the other hand, please refer to Figure 2 and Fig.12 , a millimeter wave radar is also provided, comprising a millimeter wave radar processor 201 and a memory 202. The memory 202 stores a computer program that can be executed by the millimeter wave radar processor 201; when the computer program is executed by the millimeter wave radar processor 201, the Doppler phase difference compensation method described in any embodiment of the present application is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0204] In another aspect of the embodiment of the present application, a vehicle is provided, including an on-board assisted driving system, wherein the on-board assisted driving system includes an on-board central control system and a data acquisition unit in communication with the on-board central control system. The data acquisition unit includes the millimeter wave radar described in any embodiment of the present application, or the data acquisition unit includes an on-board radar, and the on-board radar is loaded with the computer program product described in any embodiment of the present application.

[0205] On the other hand, an embodiment of the present application further provides a computer program product, including a computer program. When the computer program is executed by a processor, the Doppler phase difference compensation method described in any embodiment of the present application is implemented and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0206] On the other hand, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned Doppler phase difference compensation method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0207] The computer-readable storage medium is, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0208] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0209] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0210] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A Doppler phase difference compensation method, characterized in that: include: Acquire echo data corresponding to all Chirp waveform signals transmitted in time-sharing manner by multiple transmission channels within a frame period; wherein a single transmitted Chirp waveform signal is a DDMA_MIMO waveform, and Chirp waveform signals corresponding to multiple transmission channels transmitted in time-sharing manner constitute a TDMA_MIMO waveform; Performing distance-dimensional FFT processing on the echo data; Demodulate the DDMA_MIMO waveform to obtain separate channel data corresponding to each DDMA_MIMO waveform; Based on the separated channel data corresponding to each DDMA_MIMO waveform, all or part of the channel data within each DDMA_MIMO waveform are subjected to angle-dimensional FFT processing to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation; The reference angle spectrum is used to determine a Doppler compensation speed, and Doppler phase difference compensation is performed on all DDMA_MIMO channels using the Doppler compensation speed.

2. The Doppler phase difference compensation method according to claim 1, characterized in that: The method of determining the Doppler compensation speed by using the reference angle spectrum and performing Doppler phase difference compensation on all DDMA_MIMO channels by using the Doppler compensation speed includes: Based on the target ambiguous speed determined by demodulating the DDMA_MIMO waveform, determining the optional hypothetical speeds for Doppler phase difference compensation corresponding to different preset speed ambiguities according to the maximum unambiguous speed, the preset speed ambiguity and the maximum speed measurement range determined by the waveform parameters of each DDMA_MIMO waveform; Through each of the optional assumed speeds, Doppler phase difference compensation is performed on multiple groups of TDMA_MIMO channels in the TDMA_MIMO waveform respectively; wherein each group of TDMA_MIMO channels includes channels in two adjacent DDMA_MIMO waveforms transmitted in time division; Performing angle-dimensional FFT processing on each group of TDMA_MIMO channels after Doppler phase difference compensation to obtain azimuth angle spectra of each group of TDMA_MIMO channels under each of the optional assumed speeds; According to the correlation between the azimuth angle spectrum of each group of TDMA_MIMO channels at each optional assumed speed and the reference angle spectrum, an optional assumed speed corresponding to the angle spectrum data whose correlation meets a preset threshold condition is selected to determine the Doppler compensation speed; Based on the Doppler compensation speed, Doppler phase difference compensation is performed on all DDMA_MIMO channels.

3. The Doppler phase difference compensation method according to claim 2, characterized in that: The step of selecting, according to the correlation between the azimuth angle spectrum of each group of TDMA_MIMO channels at each optional assumed speed and the reference angle spectrum, the optional assumed speed corresponding to the angle spectrum data whose correlation satisfies a preset threshold condition, and determining the Doppler compensation speed comprises: Compare the azimuth angle spectrum of each group of TDMA_MIMO channels under each of the optional assumed speeds with the reference angle spectrum, and select the optional assumed speed in each group of TDMA_MIMO channels whose azimuth angle spectrum is the same as or has the greatest correlation with the reference angle spectrum and satisfies a preset threshold condition as a candidate compensation speed; Determining whether the selected compensation speeds are equal; If they are not equal, the data in the current frame period is considered invalid; If they are equal, the to-be-selected compensation speed is used as the Doppler compensation speed.

4. The Doppler phase difference compensation method according to claim 2, characterized in that: Also includes: Based on the waveform parameters of each DDMA_MIMO waveform, the maximum unambiguous speed is determined according to the following formula: Where c refers to the speed of light, f refers to the signal frequency, and T refers to the DDMA_MIMO waveform period.

5. The Doppler phase difference compensation method according to claim 2, characterized in that: Based on the target ambiguous speed determined by demodulating the DDMA_MIMO waveform, the maximum unambiguous speed, the preset speed ambiguity and the maximum speed measurement range determined according to the waveform parameters of each DDMA_MIMO waveform, the optional hypothetical speed for Doppler phase difference compensation corresponding to different preset speed ambiguities is determined using the following formula: Wherein, V refers to the target blur speed; V k It refers to the optional assumed velocity for Doppler phase difference compensation; V max It refers to the maximum unambiguous speed of the DDMA_MIMO waveform, which can be obtained through the DDMA_MIMO waveform parameters; k refers to the velocity ambiguity; V r- It refers to the maximum speed measurement range in the negative direction; V r+ Refers to the maximum speed measurement range in the positive direction.

6. The Doppler phase difference compensation method according to claim 1, characterized in that: The method of performing angle-dimensional FFT processing on all or part of the channel data within each DDMA_MIMO waveform based on the separated channel data corresponding to each DDMA_MIMO waveform to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation includes: Based on the separated channel data corresponding to each DDMA_MIMO waveform, all or part of the channel data within each DDMA_MIMO waveform are subjected to angle-dimensional FFT processing to obtain the azimuth-dimensional angle spectrum corresponding to each DDMA_MIMO waveform; The plurality of azimuth angle spectra are non-coherently accumulated to obtain a reference angle spectrum for TDMA_MIMO Doppler phase difference compensation.

7. The Doppler phase difference compensation method according to claim 6, characterized in that: The separated channel data corresponding to each DDMA_MIMO waveform is subjected to angle-dimensional FFT processing on all or part of the channel data within each DDMA_MIMO waveform to obtain the azimuth-dimensional angle spectrum corresponding to each DDMA_MIMO waveform, including: Based on the separated channel data T1, T2 and T7 corresponding to the first DDMA_MIMO waveform, a first MIMO virtual array formed by the channel data T1, T2 and T7 is obtained; based on the separated channel data T3, T8 and T9 corresponding to the second DDMA_MIMO waveform, a second MIMO virtual array formed by the channel data T3, T8 and T9 is obtained; based on the separated channel data T4, T5 and T10 corresponding to the third DDMA_MIMO waveform, a third MIMO virtual array formed by the channel data T4, T5 and T10 is obtained; based on the separated channel data T6, T11 and T12 corresponding to the fourth DDMA_MIMO waveform, a fourth MIMO virtual array formed by the channel data T6, T11 and T12 is obtained; The MIMO virtual arrays composed of channel data T1 and T7, T3 and T9, T4 and T10, T6 and T12 are respectively subjected to angle-dimensional FFT processing in the azimuth dimension to obtain azimuth-dimensional angle spectra corresponding to the first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform, respectively.

8. The Doppler phase difference compensation method according to claim 7, characterized in that: Also includes: All Chirp waveform signals within a frame period are transmitted through the transmitting antenna according to the preset MIMO waveform; The preset MIMO waveform includes a first DDMA_MIMO waveform, a second DDMA_MIMO waveform, a third DDMA_MIMO waveform and a fourth DDMA_MIMO waveform which are transmitted in time division and respectively include the same number of Chirp waveforms. The first DDMA_MIMO waveform, the second DDMA_MIMO waveform, the third DDMA_MIMO waveform and the fourth DDMA_MIMO waveform constitute a TDMA_MIMO waveform.

9. A millimeter wave radar, characterized in that: The invention comprises a millimeter wave radar processor and a memory, wherein the memory stores a computer program executable by the millimeter wave radar processor; When the computer program is executed by the millimeter-wave radar processor, the Doppler phase difference compensation method of the millimeter-wave radar according to any one of claims 1 to 8 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the Doppler phase difference compensation method according to any one of claims 1 to 8 is implemented.

11. A means of transport, characterized in that: The vehicle-mounted assisted driving system includes a vehicle-mounted central control system and a data acquisition unit that is communicatively connected to the vehicle-mounted central control system; The data acquisition unit includes the millimeter wave radar as claimed in claim 9; or, The data acquisition unit comprises a vehicle-mounted radar, and the vehicle-mounted radar is loaded with the computer program product according to claim 10.

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