CN118191818A

CN118191818A - Target speed and distance determination method, device and radar

Info

Publication number: CN118191818A
Application number: CN202410447691.3A
Authority: CN
Inventors: 刘升恒; 石峰; 黄永明; 杨绿溪
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2024-04-15
Filing date: 2024-04-15
Publication date: 2024-06-14

Abstract

The present invention discloses a method, device and radar for determining target speed and distance, and the method comprises: designing the waveform of the radar's transmitting signal; transmitting a frequency modulated continuous wave signal to the target through the transmitter of the local radar, and receiving the receiving signal reflected by the target through the receiver of the local radar; mixing the receiving signal reflected by the target with the transmitting signal and performing a two-dimensional fast Fourier transform to obtain a range Doppler matrix; performing multi-channel incoherent superposition on the obtained range Doppler matrix; separating the real target through the Hadamard product separation method to obtain a range Doppler spectrum containing only the real target; performing peak search on the range Doppler spectrum containing only the real target, taking the peak point as the point where the target is located, and determining the distance and speed of the target. The present invention is applicable to the target matching problem of any MIMO radar with M transmitting array elements and N receiving array elements.

Description

Target speed and distance determining method and device and radar

Technical Field

The present invention relates to radar technology, and in particular, to a method and apparatus for determining a target speed and a target distance, and a radar.

Background

Frequency Division Multiple Access (FDMA) in Frequency Modulated Continuous Wave (FMCW) radar includes ranging multiple access (RDMA) and doppler multiple access (DDMA) and Code Division Multiple Access (CDMA). Both DDMA and RDMA FMCW radars have advantages and disadvantages. DDMA and RDMA FMCW radars may utilize simultaneous transmission of multiple antennas. RDMA FMCW radar moves a target along the range dimension, which maintains the blur free speed v _{max_RDMA}＝v_max, but results in a reduced blur free range r _{max_RDMa}＝r_max/N_TX. On the other hand, the DDMA FMCW radar moves the target in the doppler direction. Thus, the DDMA FMCW radar maintains a blur-free distance r _{max_DDMA}＝r_max. However, the non-ambiguous speed of the DDMA FMCW radar is v _{max_DDMA}＝v_max/N_TX. For example, for a DDMA FMCW radar with three TX antennas, the unambiguous speed is v _{max_DDMA}＝v_max/3. In the case of QPSK modulation with three TX antennas for DDMA FMCW radar, the ambiguity free speed is v _{max_DDMA_QPSK}＝v_max/4.

To compromise the non-ambiguous distance and speed, nguyen et al propose a method for implementing Multiple Input Multiple Output (MIMO) functionality using an FMCW radar combining RDMA and DDMA. RDMA and DDMA are implemented using varying center frequency and Quadrature Phase Shift Keying (QPSK) modulation, respectively. This approach enables simultaneous transmission of chirp waveforms from multiple Transmit (TX) antennas. The system has the following advantages over existing use of DDM, taking advantage of these advantages of RDMA and DDMA in combination to balance the performance of FMCW MIMO radar in terms of angular resolution, no ambiguity distance, and no ambiguity speed. In particular, FMCW radar systems incorporating RDMA and DDMA allow for an increased number of TX antennas in MIMO applications. However, the existing method for determining the speed and the distance of the target has poor matching effect when a plurality of objects with blurred distances are obtained, and the matching effect on the guardrail targets is poor.

Disclosure of Invention

The invention aims to: the invention aims to provide a target speed and distance determining method, a target speed and distance determining device and a radar, which are suitable for the problem of target matching of MIMO radars of any M transmitting array elements and N receiving array elements.

The technical scheme is as follows: the invention relates to a target speed and distance determining method, which comprises the following steps:

Designing waveforms of radar transmitting signals, wherein the transmitting signals comprise DDMA modulated transmitting signals and RDMA modulated transmitting signals;

Transmitting a frequency modulation continuous wave signal to a target through a transmitter of a local terminal radar, and receiving a receiving signal reflected by the target through a receiver of the local terminal radar;

Mixing a received signal reflected by a target with a transmitted signal, and performing two-dimensional fast Fourier transform to obtain a distance Doppler matrix;

Carrying out multi-channel incoherent superposition on the obtained range Doppler matrix;

separating out the real target by a Hadamard product separation method to obtain a range Doppler spectrogram only containing the real target;

And (3) carrying out peak search on the range Doppler spectrogram only comprising the real target, taking the peak point as the point where the target is located, and determining the range and the speed of the target.

Further, the radar is a MIMO radar, the transmitting antenna array of the transmitter and the receiving antenna array of the receiver are equivalent to a virtual array through position summation, the transmitting antenna array includes an RDMA modulation antenna array and a DDMA modulation antenna array, and a first array element of the RDMA modulation antenna array and a first array element of the DDMA modulation antenna array share the same array element.

Further, designing a waveform of a transmission signal of the radar, including:

setting the number of RDMA modulation antennas and the number of DDMA modulation antennas;

Setting the number of fast time dimension empty frequency bands and the number of slow time dimension empty frequency bands;

setting modulation frequency of RDMA modulation antenna transmitting waveform and offset frequency of each antenna;

And setting the modulation frequency and the modulation phase of the transmission waveform of the DDMA modulation antenna.

Further, mixing the received signal reflected by the target with the transmitted signal, and performing two-dimensional fast fourier transform to obtain a range-doppler matrix, including:

Firstly, carrying out frequency mixing processing on a received signal and a transmitted signal, wherein after the frequency mixing processing, the obtained intermediate frequency signal is the product of the transmitted signal and the received signal so as to realize frequency conversion and frequency spectrum shifting of the signals;

Then, a two-dimensional fast fourier transform (2D-FFT), that is, a doppler-dimensional fourier transform and a range-dimensional fourier transform, is performed on the mixed intermediate frequency signal to obtain a range-doppler matrix, so as to analyze the signal in a two-dimensional frequency domain.

Further, the obtained range-doppler matrix is subjected to multi-channel incoherent superposition, specifically: the range-doppler matrix data for each channel is taken absolute value and accumulated in the channel dimension.

Further, the Hadamard product separation method comprises the following steps:

converting the original range-Doppler matrix into a binary version through 2D-CFAR to obtain a range-Doppler matrix of the binary version;

circularly downshifting a binary version of the range-doppler matrix according to a modulation frequency of an RDMA modulated antenna signal designed in a waveform of a transmit signal of the designed radar;

circularly downshifting and rightwards a binary version of the range-doppler matrix according to the center frequency and modulation phase of the DDMA modulation antenna signal designed in the waveform of the transmission signal of the designed radar;

And carrying out Hadamard product on all the obtained range Doppler matrixes and the original range Doppler matrix, and separating out the real target to obtain a final range Doppler diagram only retaining the real target result.

Further, the method converts the original range-doppler matrix into a binary version through 2D-CFAR, specifically: when the external interference intensity changes, the threshold value of the radar is automatically adjusted, so that the false alarm probability of the radar is kept constant; when the detected value is greater than the adaptive threshold, then the target value is considered to be set to 1; when the detected value is less than the adaptive threshold, then the noise is considered to be set to 0.

Further, the peak search is as follows: and extracting peaks from the range-Doppler graph which only retains the true target result, wherein the peak points are the points of the true range and speed of the target in the range-Doppler graph.

In one embodiment of the present invention, a target angle and distance determining apparatus includes: the system comprises a signal transceiving module, an analog-to-digital conversion (ADC) module, a two-dimensional fast Fourier transform (2D-FFT) module and a target matching module, wherein:

The signal receiving and transmitting module is used for transmitting a designed frequency modulation continuous wave signal to a target through a transmitter of the local end radar, receiving a receiving signal reflected by the target through a receiver of the local end radar, wherein the receiver comprises a receiving antenna array and a mixer, and the mixer is used for mixing the receiving signal and the transmitting signal to form an intermediate frequency signal;

The ADC module is used for converting the analog intermediate frequency signal into a digital intermediate frequency signal after sampling;

the 2D-FFT module is used for converting the digital intermediate frequency signal into a distance Doppler matrix through discrete Fourier transform and performing multi-channel incoherent superposition;

and the target matching module separates out a real target through a Hadamard product separation method and peak value search, and determines the distance and the speed of the target.

In one embodiment of the invention, a radar comprises a transmitter, a receiver and a processor, the transmitter and the receiver being respectively connected to the processor, wherein:

The transmitter is used for transmitting the frequency modulation continuous wave signal, namely a transmitting signal, to a target; the receiver comprises a receiving antenna array, a mixer and an analog-to-digital converter, wherein each array element of the receiving antenna array is used for receiving a receiving signal formed by reflecting the transmitting signal by a target, the mixer is used for mixing the receiving signal and the transmitting signal, and the analog-to-digital converter is used for converting the analog signal into a digital signal;

The processor is configured to perform the steps of the target speed and distance determination method according to any one of claims 1 to 8.

The beneficial effects are that: compared with the prior art, the invention has the advantages that: under the condition of not increasing the complexity of hardware, the distance and the speed of any FMCW radar can be measured and measured within the maximum non-fuzzy distance or speed of the common FMCW radar under any M transmitting and N receiving conditions, and the guardrail targets can be well measured and measured.

Drawings

FIG. 1 is a diagram of an application environment for a target speed and distance determination method in one embodiment;

FIG. 2 is a flow chart of a method for determining a target speed and distance according to one embodiment;

figure 3 is a schematic diagram of a possible target response in the range-doppler spectrum in one embodiment;

FIG. 4 is a bird's eye view of a guardrail target generated in one embodiment;

FIG. 5 is a graph of the results of object matching with a single object in one embodiment;

FIG. 6 is a graph of the results of object matching in the case of multiple distance blurred objects in one embodiment;

FIG. 7 is a graph of the results of matching guardrail targets in one embodiment;

FIG. 8 is a graph of the results of matching of 50 point targets randomly generated in one embodiment;

FIG. 9 is a block diagram of a target speed and distance determination device in one embodiment;

Fig. 10 is a schematic diagram of the structure of the radar in one embodiment.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The application aims to provide a target speed and distance determining method, which meets the requirement of any given number of transmitting antennas and receiving antennas, and can realize target matching of the distance and the speed within the maximum non-fuzzy distance and the speed of the FMCW radar by designing the waveform of the transmitting signals of the MIMO radar, including the matching of the distance and the matching of the speed. The target speed and distance determining method can be applied to the application environment shown in fig. 1. Wherein the radar 102 has a transmitter and a receiver, the radar 102 is capable of transmitting a Frequency Modulated Continuous Wave (FMCW) signal to a target 104 located around the radar 102 by the transmitter of the local terminal, and receiving a received signal reflected by the target 104 by the receiver of the local terminal, the radar 102 performs the target speed and distance determination method of various embodiments of the present application on the target 104 to determine the speed and distance of the target 104 relative to the radar 102.

The method is suitable for the target matching problem of the MIMO radar of any M transmitting array elements and N receiving array elements. The method comprises the following steps: designing waveforms of transmitting signals of the MIMO radar; mixing a received signal reflected by a target with a transmitted signal, and performing two-dimensional fast Fourier transform (2D-FFT) to obtain a range-Doppler matrix; carrying out multi-channel incoherent superposition on the obtained range Doppler matrix; separating out a real target by a Hadamard product separation method; and finally, determining the distance and the speed of the target through peak value searching.

In one embodiment, as shown in fig. 2, there is provided a target speed and distance determining method, including the steps of:

s210, designing waveforms of transmitting signals of the MIMO radar.

Illustratively, in this step, it is assumed that for a MIMO radar system, the transmitter antenna array includes an RDMA modulation antenna array and a DDMA modulation antenna array. Radar modulates a transmit signal waveform with RDMA using N Transmit (TX) antennas and DDMA using M Transmit (TX) antennas. Because one of the antennas modulates the transmit signal waveform with both RDMA and DDMA, the total number of transmit antennas N _TX = (n+m-1).

In RDMA modulation, where a frequency perturbation Δf _l is added to the RDMA transmit antenna, the expression for the RDMA modulated transmit signal can be written as:

Wherein S _TR (t) is an RDMA modulated transmission signal, l represents the 1+1th RDMA modulation antenna, A _T is the amplitude of the transmission signal, f ₀ is the starting frequency, f _mr is the modulation frequency of RDMA, k is the slope of chirp in Hz/S, Is the starting phase of the transmitted signal, t is the time within the sweep, denoted as fast time, Δf _l is the frequency offset corresponding to the different antennas, and Δf ₀ =0.

Designing a transmit signal of a MIMO radar requires changing the center frequency of the DMMA modulated transmit signal, and for simplicity, assuming uniform variation between antennas here, the expression for the DDMA modulated transmit signal may be written as:

Where S _TD (t) is a DDMA modulated transmit signal, l ₁ denotes the l ₁ +1th DDMA modulated antenna, A _T is the amplitude of the transmit signal, f ₀ is the starting frequency, f _mv is the modulation frequency of the DDMA, k is the slope of chirp in Hz/S, For modulating phase,Is the initial phase of the transmitted signal, and t is the time within the sweep, denoted as the fast time.

S220, transmitting signals to the target through a transmitter of the local terminal radar, and receiving received signals reflected by the target through a receiver of the local terminal radar.

S230, mixing the received signal reflected by the target with the transmitted signal, and performing two-dimensional fast Fourier transform (2D-FFT) to obtain a range-Doppler matrix.

In one embodiment, step S230 includes the following steps S231-S232.

S231, mixing the received signal with the transmitted signal to obtain an intermediate frequency signal;

Illustratively, in this step, if the target object is illuminated by a radar beam (i.e., radar transmit signal), a portion of the signal energy is reflected back to the radar's receiver. After the Round Trip Delay Time (RTDT) τ, the received signal will be a attenuated, time-delayed, phase-shifted version of the transmitted signal. The received signal has the following form:

where s _R (t) is the received signal, A _R is the amplitude of the received signal, Due to the additional phase shift caused during signal propagation. After mixing, the intermediate frequency signal is the product of the transmit signal and the receive signal. The corresponding intermediate frequency signal at the output of the low pass filtered receiver is:

Therein, wherein Is a phase modulation term, and if the influence of random phase error epsilon during DDMA phase modulation is considered, the expression of the intermediate frequency signal can be expressed as:

wherein s _IF (t) is an intermediate frequency signal after mixing the received signal with the transmitted signal. Representing the random phase error in the first ₁ +1 DDMA modulation antenna.

S232, performing 2D-FFT on the obtained intermediate frequency signal;

Illustratively, in this step, it may be considered that in each chirp, the target is considered stationary, but between the chirps, the target is considered moving. If the velocity of the target is assumed to be constant over the duration of the transmitted signal transmission, this velocity can lead to a change in target position between the chirp. In this case, τ can be written as:

wherein R is the distance of the target, V is the speed of the target, t _s is the time of the slow time dimension, and c is the speed of light. In a real-world situation there will be noise and neglecting the 1/c ² term, the if signal model can be rewritten as:

Wherein, For the rewritten intermediate frequency signal, n (t, t _s) is additive white gaussian noise. In practice, the fast time dimension and the slow time dimension of the intermediate frequency signal are required to be sampled at the repetition frequencies of the sampling frequency f _s and the chirp signal, respectively, so as to obtain the sampled intermediate frequency signal as follows:

Wherein, For a sampled intermediate frequency signal, n=0, 1..n _f-1,n_s＝0,1,...,N_s-1,N_f is the number of samples in the fast time dimension and N _s is the number of samples in the slow time dimension. Thus, a two-dimensional discrete Fourier transform (2D-DFT) is performed along the fast and slow time dimensions, resulting in a range-Doppler matrix S (u, w), which can be expressed as:

where u and w are discrete frequency variables and S (u, w) is a two-dimensional spectrum containing information about the target distance R and velocity V. And the distance resolution deltar and the speed resolution deltav of the FMCW radar are:

ΔR＝cf_s/2kN_f (10)

ΔV＝c/2N_sT_rf₀ (11)

Where f _s is the sampling frequency, k is the slope of the chirp signal, and T _r is the duration of the chirp signal. S (u, w) can thus be expressed as a function of the target distance r and the velocity v, i.e.:

S(r,v)＝S(u(r),w(v)) (12)

Wherein,

Where u (r) represents the value of the discrete frequency variable u when the target distance is r, and w (v) represents the value of the discrete frequency variable w when the target speed is v.

S240, performing multi-channel incoherent superposition on the obtained range-Doppler matrix.

Illustratively, in this step, the range-doppler matrices of all the receiving antennas are superimposed to obtain:

Wherein, For the range-doppler matrix superimposed for all the receive antennas, N _RX is the number of receive antennas and S _i (r, v) represents the range-doppler matrix for the ith receive antenna.

S250, effectively separating a real target from the mixed information by a Hadamard integration separation method.

In one embodiment, step S250 includes the following steps S251-S254.

S251, the range-Doppler matrix after the range-Doppler matrix of all the original receiving antennas is overlappedConverting to a binary version by 2D-CFAR;

illustratively, in this step, the superimposed range-Doppler matrix is first of all Writing: /(I) And Where g _i,j represents the superimposed range-Doppler matrixThe value of row i, column j, i=0, 1, …, N _f-1,j＝0,1,…,N_s -1. Let x ₁、x₂ and Δx _l be the position indices of r _mr、r_mv and Δr _l, respectively, along the fast time dimension in a ₀, and y be the position index of v _mod along the slow time dimension in a _,, they can be written as:

Wherein, Expressed as a downward rounding, For maximum unambiguous distance of FMCW radar,For maximum unambiguous speed of FMCW radar, f _mr is the modulation frequency of the RDMA signal, f _mv is the modulation frequency of the DDMA signal, B is the bandwidth of the chirp signal, and T _r is the duration of the chirp signal. N _EBR is the number of fast time dimension null bands designed when the RDMA transmission waveform is designed, N _EBD is the number of slow time dimension null bands designed when the DDMA transmission waveform is designed, N is the number of RDMA transmission antennas, M is the number of DDMA transmission antennas, and c is the light speed.

The value corresponding to the index in the point list after 2D-CFAR for all of the points in a ₀ becomes 1, and the value corresponding to the index in the point list after 2D-CFAR for all of the points in a ₀ becomes 0. The values of row i and column j in the binary version of the range-doppler matrix B ₀ may be defined as:

where g _i,j represents the value of row i and column j of B ₀.

S252, circularly downshifting a binary version of a range-Doppler matrix B ₀ according to the modulation frequency of an RDMA modulation antenna signal designed in the waveform of a transmission signal of RDMA+DDMA;

Illustratively, in this step, B ₀ is cyclically shifted down in the fast time dimension by x ₁ and Δx _l to obtain:

Wherein B _m is the mth range-Doppler matrix obtained by performing cyclic downshifting along the fast time dimension according to the position index of mx ₁+Δx_m for B ₀, G _i,j represents the value of row i and column j of B ₀.

S253, performing cyclic downshifting and rightward shifting on a binary version of the range-Doppler matrix according to the modulation frequency and the modulation phase of the DDMA modulation antenna signal designed in the waveform of the transmission signal of the designed RDMA+DDMA;

illustratively, in this step, B ₀ is shifted down and right in the fast and slow time dimensions, respectively, at the same time as x ₂ and y, respectively, to obtain:

wherein B _n+N-1 is an n+N-1-th range Doppler matrix obtained by performing cyclic downshifting of B ₀ along the fast time dimension according to the position index of nx ₂ and cyclic rightward shifting along the slow time dimension according to the position index of ny, n=1, …, M-1,

S254, carrying out Hadamard product on all the obtained B ₀、B₁、B₂、…、B_M+N-2 and A ₀ to obtain a range-Doppler spectrogram A only containing a real target.

Illustratively, in this step, a may be written as:

A＝A₀⊙B₀⊙B₁⊙...⊙B_M+N-2 (20)

Figure 3 shows a possible target response in the range-doppler spectrum (n=m=3, N _EBD＝N_EBR =1). From the figure, it can be seen that the Hadamard product of B ₀、B₁、B₂、…、B_M+N-2 can be taken to obtain that only the matrix value of the correct position and speed of the target is 1, and the other matrix values are 0. And thus again hadamard product with a ₀, the incorrect position, velocity of the target in the range-doppler spectrum a ₀ becomes 0 while the correct position, velocity and phase of the target remain unchanged because they are multiplied by 1.

And S260, searching the range-Doppler spectrogram A through a peak value, and taking the peak value point as the point where the target is located.

Simulation experiment

The present invention will be described in detail below with reference to the drawings and the detailed description, and it should be noted that the present embodiment is not limited to the embodiments, but is used to verify the validity of the invention.

The invention provides a target speed and distance determining method, and in order to verify the effectiveness of the method, an example flow of the invention is given below.

(1) Simulation experiment parameter setting

Table 1 simulation experiment parameter settings

Simulation experiments were set as in table 1, in this example experiment, the number of DDMA modulation antennas n=14 and the number of rdma modulation antennas n=3 were considered with random phase errors. The number of fast-time dimension null bands N _EBR =1 and the number of slow-time dimension null bands N _EBD =2. And Δr ₁ and Δr ₂ were set to-4 m and 4m, respectively. The guardrail targets are generated by MATLAB's own Driving Scenario Designer, and FIG. 4 is a bird's eye view of the generated guardrail targets.

(2) Experimental results

Fig. 5 shows the result of the object matching in the case of a single object. Fig. 6 shows the result of the matching of a plurality of distance fuzzy objects. Fig. 7 shows the result of matching the fence target, and fig. 8 shows the result of matching the 50 point targets generated randomly. Wherein the red circles represent the true speed and distance of the target and the yellow dots represent the speed and distance of the algorithmically matched target. The RDMA+DDMA radar target matching algorithm can well realize the matching of the distance and the speed of a single target, a plurality of distance fuzzy targets and a fence target by considering the random phase error.

In one embodiment, as shown in fig. 9, there is provided a target speed and distance determining apparatus 800 comprising: a signal transceiving module 801, an analog-to-digital conversion (ADC) module 802, a two-dimensional fast fourier transform (2D-FFT) module 803, a target matching module 804, wherein:

The signal transceiver module 801 is configured to transmit a designed frequency modulated continuous wave signal to a target through a transmitter of the local end radar, and receive a received signal reflected by the target through a receiver of the local end radar, where the receiver includes a receiving antenna array and a mixer, and the mixer is configured to mix the received signal with the transmitted signal to form an intermediate frequency signal.

The ADC module 802 is configured to convert the analog intermediate frequency signal into a digital intermediate frequency signal after sampling;

The 2D-FFT module 803 is configured to convert the digital intermediate frequency signal into a range-doppler matrix through discrete fourier transform, and perform multi-channel incoherent superposition;

The target matching module 804 separates the real target by the Hadamard product separation method and the peak search, and determines the distance and the speed of the target.

The specific definition of the target speed and distance determining device 800 may be referred to the definition of the target speed and distance determining method hereinabove, and will not be described herein. The various modules of the target speed and distance determination apparatus 800 described above may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.

In one embodiment, as shown in fig. 10, a radar 900 is provided, including a transmitter 901, a receiver 902, and a processor 903, the transmitter 901 and the receiver 902 being respectively coupled to the processor 903.

A transmitter 901 for transmitting an FMCW signal to a target, a transmitting antenna array of the transmitter being composed of a DDMA modulation antenna array and an RDMA modulation antenna array;

The receiver 902 includes a receiving antenna array, a mixer, and an analog-to-digital converter, where each element of the receiving antenna array is configured to receive a received signal that is reflected by the target. The mixer mixes the received signal with the transmitting signal and then samples the mixed signal to obtain an intermediate frequency signal; the analog-to-digital converter is used for converting the analog signal into a digital signal.

The processor 903 performs the following steps:

performing two-dimensional fast Fourier transform on the intermediate frequency signal to obtain a distance Doppler matrix;

non-coherent accumulation is carried out on the distance Doppler matrix of each receiving antenna;

converting the range-Doppler matrix into a binary range-Doppler matrix through two-dimensional constant false alarm rate detection;

circularly shifting the binary range-doppler matrix by the method described above to obtain a new range-doppler matrix;

carrying out Hadamard product on all the range Doppler matrixes to obtain a range Doppler matrix only containing a real target;

The range-doppler matrix, which contains only real targets, locates the speed and range of the target by peak searching.

The foregoing description of the embodiments of the invention is not intended to limit the scope of the invention, but rather to cover any modifications, equivalents, improvements, etc. that fall within the spirit and scope of the present invention.

Claims

1. A method for determining a target speed and distance, comprising the steps of:

2. The method for determining the target speed and distance according to claim 1, wherein the radar is a MIMO radar, the transmitting antenna array of the transmitter and the receiving antenna array of the receiver are equivalent to a virtual array by position summation, the transmitting antenna array includes an RDMA modulation antenna array and a DDMA modulation antenna array, and a first element of the RDMA modulation antenna array and a first element of the DDMA modulation antenna array share the same element.

3. A method of determining target speed and distance according to claim 1, wherein designing the waveform of the radar transmit signal comprises:

4. The method of claim 1, wherein mixing the received signal reflected from the target with the transmitted signal and performing a two-dimensional fast fourier transform to obtain the range-doppler matrix comprises:

5. The method for determining the velocity and the distance of a target according to claim 1, wherein the multi-channel incoherent superposition is performed on the obtained distance doppler matrix, specifically: the range-doppler matrix data for each channel is taken absolute value and accumulated in the channel dimension.

6. The method of claim 1, wherein the hadamard product separation method comprises:

7. The method of claim 6, wherein the converting the original range-doppler matrix into a binary version by 2D-CFAR is specifically: when the external interference intensity changes, the threshold value of the radar is automatically adjusted, so that the false alarm probability of the radar is kept constant; when the detected value is greater than the adaptive threshold, then the target value is considered to be set to 1; when the detected value is less than the adaptive threshold, then the noise is considered to be set to 0.

8. The method of claim 1, wherein the peak search is: and extracting peaks from the range-Doppler graph which only retains the true target result, wherein the peak points are the points of the true range and speed of the target in the range-Doppler graph.

9. A target angle and distance determining apparatus, comprising: the system comprises a signal transceiving module, an analog-to-digital conversion (ADC) module, a two-dimensional fast Fourier transform (2D-FFT) module and a target matching module, wherein:

10. A radar comprising a transmitter, a receiver and a processor, the transmitter and the receiver being respectively coupled to the processor, wherein:

The transmitter is used for transmitting the frequency modulation continuous wave signal, namely a transmitting signal, to a target; the receiver comprises a receiving antenna array, a mixer and an analog-to-digital converter, wherein each array element of the receiving antenna array is used for receiving a receiving signal formed by reflecting the transmitting signal by a target; the mixer is used for mixing a received signal and a transmitted signal, and the analog-to-digital converter is used for converting an analog signal into a digital signal;