TDM and DDM combined radar waveform and signal processing method and device and medium

Abstract

The invention relates to the technical field of MIMO radar, and discloses a TDM and DDM combined radar waveform and signal processing method and device and a medium, and the device comprises a modulation signal transmitting module, an echo signal receiving module and an echo signal processing module. The problem of fuzzy velocity reduction caused by TDM is solved through slow time random sampling, the waveform can be well applied to a large-scale array, velocity ambiguity is avoided, the utilization rate of the Doppler frequency band is improved, the accuracy of target detection is improved through the wide Doppler sub-band, and meanwhile, for the waveform, the accuracy of target detection is improved. According to the method, a corresponding signal processing flow is provided, a method for carrying out cyclic correlation by utilizing the template to carry out channel separation is provided, the transmitting channels of the corresponding targets can be rapidly and accurately separated, the angle measurement requirement can be met, and the method can be compatible with a traditional FMCW radar and has high application flexibility.

Description

Technical Field

[0001] The present invention relates to the technical field of MIMO radar, and in particular to a radar waveform and signal processing method, device and medium combining TDM and DDM. Background Art

[0002] Multiple-input Multiple-output (MIMO) radar is a radar that uses multiple antennas to transmit and receive signals at both the transmitting and receiving ends. MIMO radar processes signals in multiple dimensions and uses the position relationship of the transmitting and receiving array elements to synthesize a virtual array, expand the radar aperture, and achieve high-precision detection and tracking of targets. Different transmitting antennas are assigned to different time slots to virtualize M×N channel data, and the corresponding relationship between each channel data and the transmitting antenna is determined. The channel data is rearranged according to the position relationship of the virtual array elements to estimate the target spatial spectrum.

[0003] TDM (Time Domain Multiplexing) waveform is a waveform design method that divides radar transmission in time. Different transmitting antennas are used in different time slots to separate the transmission channels. Traditional TDM waveform uses fixed-order transmission. There are large gaps in time between each transmission, which causes a decrease in the unambiguous speed. At the same time, there is a coupling between speed and space. On a large-scale array, as the number of transmissions increases, the unambiguous speed further decreases, making it difficult for the TDM waveform to meet the requirements of the speed measurement range.

[0004] DDM (Doppler Domain Multiplexing) waveform is a waveform design method based on Doppler frequency. It realizes simultaneous detection and tracking of multiple targets by dividing the radar transmission signal in the Doppler domain. DDM achieves channel separation by designing different transmission initial phases in slow time so that different transmitting antennas occupy different Doppler frequency bands. DDM waveform allows multiple transmitting antennas to transmit at the same time, reducing time waste and unambiguous speed improvement. However, there is a problem of determining the correspondence between Doppler frequency bands and transmitting antennas. For large-scale arrays, the more transmitting antennas there are, the more Doppler sub-bands need to be divided, which will lead to frequency band congestion and affect target detection.

[0005] Therefore, for large-scale arrays, using the above two waveforms alone cannot effectively solve the channel separation problem. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a radar waveform and signal processing method, device and medium combining TDM and DDM, which solves the problems raised in the above background technology.

[0007] To solve the above technical problems, according to one aspect of the present invention, more specifically, a radar waveform and signal processing method, device and medium combining TDM and DDM, comprising the following steps:

[0008] S1. Divide all the M transmitting antennas to be allocated into M Group group, where M can be Group divisibility;

[0009] S2. Determine the multiplexing times of each group of transmissions and determine M Group A random transmission sequence of the group, and at the same time, determining the initial phase of each transmitting antenna in each time slot, and transmitting a signal according to the determined initial transmission phase, and receiving an echo signal;

[0010] S3, mixing and sampling the echo signal and the reference signal, and performing distance dimension FFT on the sampled signal;

[0011] S4, performing a slow-time zero-filled FFT (2DFFT) according to each set of transmission sequences determined in S2, and dividing the obtained results according to Doppler sub-bands;

[0012] S5, performing non-coherent accumulation on the Doppler sub-band dimension, the transmission group dimension, and the receiving channel dimension;

[0013] S6, performing CFAR detection on the incoherent accumulation result, and extracting the 2DFFT data in all sub-bands corresponding to each target;

[0014] S7, cyclically correlate the target data and the template data, record the displacement times corresponding to the maximum value, which is the position corresponding to the first transmitting antenna, and sequentially retrieve the remaining transmitting channel data;

[0015] S8, rearrange all channel data according to the virtual channel positions, perform angle-dimensional FFT on the rearranged data, and obtain the target spatial spectrum;

[0016] S9, performing CFAR detection on the spatial spectrum to obtain angle information of the target;

[0017] S10. Output the distance, speed, angle, and signal-to-noise ratio information of the target.

[0018] Furthermore, it comprises a modulation signal transmitting module, an echo signal receiving module and an echo signal processing module, characterized in that the modulation signal transmitting module: is used for modulation signal generation and signal transmission;

[0019] Echo signal receiving module: used to receive the signal transmitted by the modulated signal transmitting module;

[0020] Echo signal processing module: used to perform FFT on the echo signal in distance, velocity and angle dimensions.

[0021] Furthermore, the working process of the modulation signal transmitting module is as follows:

[0022] (1) Modulate the signal and generate a random Tx transmission sequence;

[0023] (2) Determine the transmitting subarray according to the current pulse index, and calculate the modulation phase in the transmission according to the subarray information;

[0024] (3) Generate a chirp signal and change the initial phase through a phase shifter;

[0025] (4) Select the corresponding Tx group and transmit the corresponding modulated signal.

[0026] Furthermore, the workflow of the echo signal processing module is:

[0027] (1) Rearrange the data according to the transmission sequence, fill the rearranged data with zeros and perform velocity-dimensional FFT;

[0028] (2) Grouping the velocity dimension according to the number of sub-bands and performing incoherent accumulation of the channel dimension and sub-band dimension;

[0029] (3) Separate the transmission channels according to the target and rearrange the channel data according to the virtual channel position relationship to obtain the target spatial spectrum;

[0030] (4) Perform CFAR detection on the spatial spectrum, obtain target information, and transmit the target information.

[0031] Furthermore, the method of transmitting the packet is:

[0032] (1) Determine the number of groups M required Group , and M Group Can divide all Tx numbers M, that is, each group contains Tx;

[0033] (2) Determine the Tx number in each group in turn by sampling without replacement.

[0034] Furthermore, the method of transmitting sequencing is:

[0035] (1) Determine the number of multiplexing times N for each group of Tx, then the total number of transmitted chirps is M Group ×N, all Tx groups complete one transmission, which is called a Burst, that is, a total of N Bursts are transmitted;

[0036] (2) Determine the transmission order within each Burst, that is, generate a 1 to M GroupA random sort of all Burst emission orders form a 1×NM Group An array that records the Tx group number of each chirp;

[0037] (3) According to the order of each Burst, determine the transmission time of each Tx group.

[0038] Furthermore, the DDM phase modulation method is:

[0039] (1) Determine the number of empty bands k that need to be reserved on the Doppler spectrum empty , and meets k empty >1, the number of sub-bands divided on the Doppler spectrum is k band =k empty +m;

[0040] (2) Calculate the modulation phase during transmission according to the following formula:

[0041]

[0042] Where, p represents the pth Tx group; n p,r represents the chirp number of the rth transmission of the group Tx; q represents the qth Tx in the group; and in this application, n p,r is a set of random increasing sequences that satisfy the above constraints on the interval between two transmissions of the same Tx group: 1≤n p,r+1 -n p,r ≤2M Group -1;

[0043] (3) The phase modulation of each Tx in the group is completed through a high-precision phase shifter, and the modulated signal is transmitted simultaneously.

[0044] Furthermore, the method of the slow time zero-filling FFT is:

[0045] (1) According to the transmission sequence, from all M Group Select N echo data corresponding to one Tx group from among the ×N echo data;

[0046] (2) Fill the N echo data into the corresponding transmission sequence according to the transmission sequence, and fill 0 in the position where the Tx group does not transmit, to construct a 1×NM Group The data matrix of

[0047] (3) Perform NM on the data matrix Group FFT of the points.

[0048] Furthermore, the channel separation circular correlation method is:

[0049] (1) According to the detected target index, take out its value at the corresponding position of all Doppler sub-bands, and construct a k-size band Array of and construct loop related templates;

[0050] (2) Calculate the circular correlation results between the template sequence and the data array;

[0051] (3) Find the peak value in the correlation result, which is the peak position of Tx with the reorganized transmission number 1. Calculate the peak positions of the remaining m-1 Txs in turn according to the Doppler sub-band width.

[0052] The beneficial effects of the radar waveform and signal processing method, device and medium combining TDM and DDM of the present invention are as follows:

[0053] The present invention combines the advantages of TDM and DDM, and solves the problem of fuzzy speed drop caused by TDM through slow time random sampling. The waveform can be well applied to large-scale arrays, avoids speed ambiguity, improves the utilization rate of Doppler frequency band, and the wider Doppler sub-band improves the accuracy of target detection. At the same time, for the waveform, the application proposes a corresponding signal processing flow, especially provides a method for channel separation by cyclic correlation using a template, which can quickly and accurately separate the transmission channels of the corresponding targets and meet the needs of angle measurement. In addition, the method proposed by itself is compatible with traditional FMCW radars. When sequencing the transmission, the transmission in sequence is the traditional FMCW waveform, which has strong application flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0055] Figure 1 It is a flow chart of a radar system based on TDM and TDM and DDM combined waveforms provided by this application.

[0056] Figure 2 This is a flow chart of a modulation signal generation method based on TDM and TDM and DDM combined waveforms provided in this application.

[0057] Figure 3 It is a schematic diagram of the modulation signal transmission module provided in this application.

[0058] Figure 4 It is a flow chart of the echo signal processing method provided in this application.

[0059] Figure 5 It is a schematic diagram of the echo signal processing module provided in this application.

[0060] Figure 6It is a schematic diagram of a radar device based on TDM and TDM and DDM combined waveforms provided in this application.

[0061] Figure 7 This is a time domain schematic diagram of a modulation signal provided by an embodiment of the present application.

[0062] Figure 8 It is a physical array schematic diagram provided by another embodiment of the present application.

[0063] Fig. 9 Is Figure 8 Schematic diagram of the virtual array obtained from the physical array shown.

[0064] Fig.10 Target velocity-amplitude spectrum in one embodiment.

[0065] Fig.11 yes Fig.10 Target velocity index in the embodiment—amplitude spectrum.

[0066] Fig.12 yes Fig.10 FIG. 1 is an FFT result diagram of S2 of the target in the embodiment.

[0067] Fig.13 yes Fig.10 Spatial FFT result diagram of the target in the embodiment.

[0068] Fig.14 It is a graph of FFT results of target velocity in another embodiment. DETAILED DESCRIPTION

[0069] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0070] like Figure 1 As shown, according to one aspect of the present invention, a radar waveform and signal processing method, device and medium combining TDM and DDM are provided, including the following steps:

[0071] S1. Divide all the M transmitting antennas to be allocated into M Group group, where M can be Group divisibility;

[0072] S2. Determine the multiplexing times of each group of transmissions and determine M Group A random transmission sequence of the group, and at the same time, determining the initial phase of each transmitting antenna in each time slot, and transmitting a signal according to the determined initial transmission phase, and receiving an echo signal;

[0073] S3, mixing and sampling the echo signal and the reference signal, and performing distance dimension FFT on the sampled signal;

[0074] S4, performing a slow-time zero-filled FFT (2DFFT) according to each set of transmission sequences determined in S2, and dividing the obtained results according to Doppler sub-bands;

[0075] S5, performing non-coherent accumulation on the Doppler sub-band dimension, the transmission group dimension, and the receiving channel dimension;

[0076] S6, performing CFAR detection on the incoherent accumulation result, and extracting the 2DFFT data in all sub-bands corresponding to each target;

[0077] S7, cyclically correlate the target data and the template data, record the displacement times corresponding to the maximum value, which is the position corresponding to the first transmitting antenna, and sequentially retrieve the remaining transmitting channel data;

[0078] S8, rearrange all channel data according to the virtual channel positions, perform angle-dimensional FFT on the rearranged data, and obtain the target spatial spectrum;

[0079] S9, performing CFAR detection on the spatial spectrum to obtain angle information of the target;

[0080] S10. Output the distance, speed, angle, and signal-to-noise ratio information of the target.

[0081] In this embodiment, a modulation signal transmitting module, an echo signal receiving module and an echo signal processing module are included, wherein the modulation signal transmitting module is used for: generating a modulation signal and transmitting the signal;

[0082] Echo signal receiving module: used to receive the signal transmitted by the modulated signal transmitting module;

[0083] Echo signal processing module: used to perform FFT on the echo signal in distance, velocity and angle dimensions.

[0084] In this embodiment, the workflow of the modulation signal transmission module is as follows:

[0085] (1) Modulate the signal and generate a random Tx transmission sequence;

[0086] (2) Determine the transmitting subarray according to the current pulse index, and calculate the modulation phase in the transmission according to the subarray information;

[0087] (3) Generate a chirp signal and change the initial phase through a phase shifter;

[0088] (4) Select the corresponding Tx group and transmit the corresponding modulated signal.

[0089] In this embodiment, the workflow of the echo signal processing module is as follows:

[0090] (1) Rearrange the data according to the transmission sequence, fill the rearranged data with zeros and perform velocity-dimensional FFT;

[0091] (2) Grouping the velocity dimension according to the number of sub-bands and performing incoherent accumulation of the channel dimension and sub-band dimension;

[0092] (3) Separate the transmission channels according to the target and rearrange the channel data according to the virtual channel position relationship to obtain the target spatial spectrum;

[0093] (4) Perform CFAR detection on the spatial spectrum, obtain target information, and transmit the target information.

[0094] In this embodiment, the method for transmitting the packet is:

[0095] (1) Determine the number of groups M required Group , and M Group Can divide all Tx numbers M, that is, each group contains Tx;

[0096] (2) Determine the Tx number in each group in turn by sampling without replacement.

[0097] In this embodiment, the method of transmitting sequencing is:

[0098] (1) Determine the number of multiplexing times N for each group of Tx, then the total number of transmitted chirps is M Group ×N, all Tx groups complete one transmission, which is called a Burst, that is, a total of N Bursts are transmitted;

[0099] (2) Determine the transmission order within each Burst, that is, generate a 1 to M Group A random sort of all Burst emission orders form a 1×NM Group An array that records the Tx group number of each chirp;

[0100] (3) According to the order of each Burst, determine the transmission time of each Tx group.

[0101] In this embodiment, the DDM phase modulation method is:

[0102] (1) Determine the number of empty bands k that need to be reserved on the Doppler spectrum empty , and meets k empty >1, the number of sub-bands divided on the Doppler spectrum is k band =k empty +m;

[0103] (2) Calculate the modulation phase during transmission according to the following formula:

[0104]

[0105] Where, p represents the pth Tx group; n p,r represents the chirp number of the rth transmission of the group Tx; q represents the qth Tx in the group; and in this application, n p,r is a set of random increasing sequences that satisfy the above constraints on the interval between two transmissions of the same Tx group: 1≤n p,r+1 -n p,r ≤2M Group -1;

[0106] (3) The phase modulation of each Tx in the group is completed through a high-precision phase shifter, and the modulated signal is transmitted simultaneously.

[0107] Furthermore, the method of the slow time zero-filling FFT is:

[0108] (1) According to the transmission sequence, from all M Group Select N echo data corresponding to one Tx group from among the ×N echo data;

[0109] (2) Fill the N echo data into the corresponding transmission sequence according to the transmission sequence, and fill 0 in the position where the Tx group does not transmit, to construct a 1×NM Group The data matrix of

[0110] (3) Perform NM on the data matrix Group FFT of the points.

[0111] Furthermore, the channel separation circular correlation method is:

[0112] (1) According to the detected target index, take out its value at the corresponding position of all Doppler sub-bands, and construct a k-size band Array of and construct loop related templates;

[0113] (2) Calculate the circular correlation results between the template sequence and the data array;

[0114] (3) Find the peak value in the correlation result, which is the peak position of Tx with the reorganized transmission number 1. Calculate the peak positions of the remaining m-1 Txs in turn according to the Doppler sub-band width.

[0115] Embodiment 1:

[0116] The transmitting array has 16 elements and the number of Tx groups is M. Group=4, each group contains four transmitting array elements, and each time a Tx group transmits simultaneously, the grouping is shown in the following table:

[0117] Table 1 Tx grouping

[0118] Tx Group 1 Tx Group 2 Tx Group 3 Tx Group 4 Tx1 Tx5 Tx9 Tx13 Tx2 Tx6 Tx10 Tx14 Tx3 Tx7 Tx11 Tx15 Tx4 Tx8 Tx12 Tx16

[0119] This embodiment describes the phase modulation process of DDMA. Figure 2 The method generates the transmission waveform in the following steps:

[0120] First, a Tx group transmission sequence is randomly generated. Each Burst contains 4 Chirps. The sequence in each Burst is a permutation of [1, 2, 3, 4]. In this embodiment, the Tx group sequencing of two Bursts is shown in the following table:

[0121] Table 2 Tx group sequencing sequence

[0122]

[0123] Then, the corresponding transmission group is selected according to Table 2, and the modulation phase in the group is calculated. In this embodiment, the number of empty bands k used for unwinding is empty =2, the total number of Doppler sub-bands is k band =6, calculate the modulation phase required for each transmission as follows:

[0124]

[0125] Where p represents the pth Tx group n p,r Indicates the chirp number of the rth transmission of the group Tx, q indicates the qth Tx in the group, and the modulation phases in the above two Bursts are shown in the following table. The empty positions in the table indicate no transmission:

[0126] Table 3 Transmit modulation phase

[0127]

[0128]

[0129] Finally, the calculated phase is sent to the transmission channel in the current Tx group, and the phase modulation is completed through the phase shifter. The four Tx in the group simultaneously transmit the phase-modulated linear frequency modulation signal. The transmission waveform is shown in the attached figure. Figure 7 shown.

[0130] Embodiment 2:

[0131] The antenna array used is Figure 8As shown, it contains 48 Tx array elements and 48 Rx array elements, and the grouping situation is that the continuous Tx in four vertical directions is 1 group, which is divided into M Group = 12 groups, the number of fast time sampling points is 256, the number of slow time Tx group multiplexing times is N = 192, the total number of chirps is 2304, then the echo data cube size is: 256 × 48 × 2304, the target information is set to: 60m, -10m / s, azimuth 10°, pitch 5°;

[0132] The signal processing flow is as follows:

[0133] 1. First, perform 256-point distance-dimensional FFT on the echo data and discard the second half of the data. At this time, the data size is 128×48×2304;

[0134] 2. Extract different Tx group data according to the Tx transmission sequence. At this time, the data size becomes 128×192×48×12;

[0135] 3. Fill the positions where the slow-time Tx group has not transmitted with 0, and the data size is 128×2304×48×12;

[0136] 4. Perform FFT processing on the slow time dimension, the result is as follows Fig.12 As shown in the figure, due to the non-uniform sampling of the slow time dimension, the side lobes of the speed dimension increase, and the peak-to-average side lobe ratio is approximately N is the number of Tx group multiplexing times, m is the number of Tx in each group, in this embodiment, N = 192, m = 4, the peak-to-average sidelobe ratio is calculated to be 16.8dB, Fig.10 The simulation results show that the peak-to-average sidelobe ratio is about 17.02dB. Fig.14 In the embodiment shown, N=768, m=12, and the peak-to-average sidelobe ratio is calculated to be 18.1 dB. Fig.14 The simulation results shown show a peak-to-average sidelobe ratio of approximately 19.53 dB;

[0137] 5. Such as Fig.13 The velocity spectrum shown is divided into data according to sub-bands. In this embodiment, the total number of frequency bands is 8, and the number of FFT points in the velocity dimension is 2304. Therefore, each sub-band contains 288 velocity units, and the size of the divided data is 128×288×8×48×12;

[0138] 6. Perform incoherent accumulation on the three dimensions of the divided data. Since the empty band does not contain the target information, the peak value of the target will not be increased during incoherent accumulation, that is, it is not advisable to set too many empty bands. Perform 2dCFAR on the 2D spectrum after incoherent accumulation, and obtain the r,v index of the target as [104,67];

[0139] 7. Separate the target channel, and extract the data of the corresponding position on the sub-band in turn according to the target index. The speed index numbers of the target in each sub-band are calculated according to the sub-band width, which are [67, 355, 643, 931, 1219, 1507, 1795, 2083]. Use the template [11110000] to perform cyclic correlation with the above sequence, and obtain the correlation peak when k=4. Therefore, the index number 931 corresponds to the Tx numbered 1 in the group, and the positions corresponding to the peak values ​​of Tx numbers 2, 3, and 4 can be obtained as 1219, 1507, and 1795 respectively;

[0140] 8. Follow Fig. 9 The position of the virtual real element is shown in the figure, and the channel data is rearranged. After windowing, a spatial dimension 2DFFT is performed. The spatial spectrum result is as follows Fig.13 As shown;

[0141] 9. Yes Fig.13 The spatial spectrum shown in the figure is subjected to 2dCFAR detection to obtain the azimuth angle and pitch angle information of the target. Steps 7 to 9 are repeated to complete the angle detection of all targets on the range-velocity spectrum.

[0142] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention also fall within the protection scope of the present invention.

Claims

1. The method for processing radar waveform signals combining TDM and DDM according to claim 1, comprising the following steps: S1. Divide all the M transmitting antennas to be allocated into M Group group, where M can be Group divisibility; S2. Determine the multiplexing times of each group of transmissions and determine M Group A random transmission sequence of the group, and at the same time, determining the initial phase of each transmitting antenna in each time slot, and transmitting a signal according to the determined initial transmission phase, and receiving an echo signal; S3, mixing and sampling the echo signal and the reference signal, and performing distance dimension FFT on the sampled signal; S4, performing a slow-time zero-filled FFT (2DFFT) according to each set of transmission sequences determined in S2, and dividing the obtained results according to Doppler sub-bands; S5, performing non-coherent accumulation on the Doppler sub-band dimension, the transmission group dimension, and the receiving channel dimension; S6, performing CFAR detection on the incoherent accumulation result, and extracting the 2DFFT data in all sub-bands corresponding to each target; S7, cyclically correlate the target data and the template data, record the displacement times corresponding to the maximum value, which is the position corresponding to the first transmitting antenna, and sequentially retrieve the remaining transmitting channel data; S8, rearrange all channel data according to the virtual channel positions, perform angle-dimensional FFT on the rearranged data, and obtain the target spatial spectrum; S9, performing CFAR detection on the spatial spectrum to obtain angle information of the target; S10. Output the distance, speed, angle, and signal-to-noise ratio information of the target.

2. According to claim 1, a radar waveform signal device combining TDM and DDM comprises a modulation signal transmitting module, an echo signal receiving module and an echo signal processing module, characterized in that: The modulation signal transmission module is used for modulation signal generation and signal transmission; Echo signal receiving module: used to receive the signal transmitted by the modulated signal transmitting module; Echo signal processing module: used to perform FFT on the echo signal in distance, velocity and angle dimensions.

3. The radar waveform signal processing device combining TDM and DDM according to claim 2, characterized in that: The working process of the modulation signal transmission module is as follows: (1) Modulate the signal and generate a random Tx transmission sequence; (2) Determine the transmitting subarray according to the current pulse index, and calculate the modulation phase in the transmission according to the subarray information; (3) Generate a chirp signal and change the initial phase through a phase shifter; (4) Select the corresponding Tx group and transmit the corresponding modulated signal.

4. The radar waveform signal processing device combining TDM and DDM according to claim 2, characterized in that: The workflow of the echo signal processing module is as follows: (1) Rearrange the data according to the transmission sequence, fill the rearranged data with zeros and perform velocity-dimensional FFT; (2) Grouping the velocity dimension according to the number of sub-bands and performing incoherent accumulation of the channel dimension and sub-band dimension; (3) Separate the transmission channels according to the target and rearrange the channel data according to the virtual channel position relationship to obtain the target spatial spectrum; (4) Perform CFAR detection on the spatial spectrum, obtain target information, and transmit the target information.

5. The radar waveform signal processing method combining TDM and DDM according to claim 1, characterized in that: The method of transmitting the packet is: (1) Determine the number of groups M required Group , and M Group Can divide all Tx numbers M, that is, each group contains Tx; (2) Determine the Tx number in each group in turn by sampling without replacement.

6. The radar waveform signal processing method combining TDM and DDM according to claim 1, characterized in that: The method of emission sequencing is: (1) Determine the number of multiplexing times N for each group of Tx, then the total number of transmitted chirps is M Group ×N, all Tx groups complete one transmission, which is called a Burst, that is, a total of N Bursts are transmitted; (2) Determine the transmission order within each Burst, that is, generate a 1 to M Group A random sort of all Burst emission orders form a 1×NM Group An array that records the Tx group number of each chirp; (3) According to the order of each Burst, determine the transmission time of each Tx group.

7. The radar waveform signal processing method combining TDM and DDM according to claim 1, characterized in that: The DDM phase modulation method is: (1) Determine the number of empty bands k that need to be reserved on the Doppler spectrum empty , and meets k empty >1, the number of sub-bands divided on the Doppler spectrum is k band =k empty +m; (2) Calculate the modulation phase during transmission according to the following formula: Where, p represents the pth Tx group; n p，r represents the chirp number of the rth transmission of the group Tx; q represents the qth Tx in the group; and in this application, n p，r is a set of random increasing sequences that satisfy the above constraints on the interval between two transmissions of the same Tx group: 1≤n p,r+1 -n p，r ≤2M Group -1; (3) The phase modulation of each Tx in the group is completed through a high-precision phase shifter, and the modulated signal is transmitted simultaneously.

8. The radar waveform signal processing method combining TDM and DDM according to claim 1, characterized in that: The method of the slow time zero-filling FFT is: (1) According to the transmission sequence, from all M GGroup × Select N echo data corresponding to one Tx group from N echo data; (2) Fill the N echo data into the corresponding transmission sequence according to the transmission sequence, and fill 0 in the position where the Tx group does not transmit, to construct a 1 × NM Group The data matrix of (3) Perform NM on the data matrix Group FFT of the points.

9. The radar waveform signal processing method combining TDM and DDM according to claim 1, characterized in that: The channel separation circular correlation method is: (1) According to the detected target index, take out its value at the corresponding position of all Doppler sub-bands, and construct a k-size band Array of and construct loop related templates; (2) Calculate the circular correlation results between the template sequence and the data array; (3) Find the peak value in the correlation result, which is the peak position of Tx with the reorganized transmission number 1. Calculate the peak positions of the remaining m-1 Txs in turn according to the Doppler sub-band width.

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