A high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar

Abstract

The present invention discloses a high-precision positioning method based on a 77GHZ vehicle-mounted millimeter-wave radar. The present invention can effectively eliminate the time-varying effect caused by changes in the scattering amplitude. Through real-time monitoring and compensation processing of the target scattering characteristics, the accuracy output of the subsequent target angle positioning is guaranteed, and the positioning deviation caused by changes in the motion state is reduced. This provides technical guarantees for the reliability of the vehicle-mounted millimeter-wave radar system in complex dynamic environments. In addition, through hierarchical signal processing and accumulation, the angular resolution and accuracy of the radar are effectively improved. Specifically, the information of multiple signal channels is combined through the accumulation process to reduce the accuracy loss caused by the short aperture. In this way, the radar can greatly improve the angular resolution without increasing the hardware cost, so that it has better target separation and recognition capabilities.

Description

Technical Field

[0001] The invention belongs to the field of radar positioning, and in particular relates to a high-precision positioning method based on a 77 GHz vehicle-mounted millimeter-wave radar. Background Art

[0002] In the 77GHz automotive millimeter-wave radar system, angle measurement is a key step in point cloud processing and coordinate generation. Currently, a sparse array antenna arrangement is widely used, and the virtual aperture is synthesized with the help of MIMO (multiple transmit and multiple receive) technology, and the angle measurement function is realized through algorithms such as FFT, MUSIC and Capon. Its common working mode is the time-sharing mode of transmission and reception, that is, N transmitting antennas transmit signals in sequence, and all receiving antennas receive signals at the same time. This process is called TDM (time division multiplexing). Although this technology can meet the basic target positioning needs of automotive millimeter-wave radar, in order to improve the accuracy of target detection, it is key to further improve the signal-to-noise ratio (SNR).

[0003] To this end, an emerging method is to use a strategy based on TDM to transmit N transmitting antennas simultaneously and receive all receiving antennas simultaneously to achieve an enhancement in the signal-to-noise ratio. However, although this improvement improves the signal-to-noise ratio, it also introduces the complexity of the signal decoupling operation, especially in the signal processing process of all receiving channels. Decoupling becomes more difficult, requiring higher precision and harsh conditions to meet the needs of angle positioning.

[0004] For example, in actual vehicle-mounted millimeter-wave radar target detection and positioning, complex and changing scenarios and multiple target types are common challenges. For stationary or slow-moving targets, the time-sharing output of MIMO has a small impact and can be basically ignored. However, when facing irregularly shaped high-speed moving targets, the time-sharing output mode may cause the target state to change within a set of time slots. This is because the target scattering intensity in the radar equation decays with the fourth power of the distance, which makes it difficult to completely eliminate the error when the receiving channel signal is decoupled. The remaining residual will increase the angle measurement error, which in turn affects the accuracy of target positioning. In addition, in high-frequency radars, the stability requirements of the device are more stringent. However, in reality, due to factors such as power supply voltage fluctuations, movement and vibration of the vehicle-mounted platform, the power output stability of the transmitting channel deteriorates, and the power instability of multiple transmitting channels directly increases the error of receiving channel signal decoupling. This will further affect the positioning accuracy of the target.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar, which solves the problems raised in the above-mentioned background technology.

[0007] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] A high-precision positioning method based on 77 GHZ vehicle-mounted millimeter-wave radar comprises the following steps:

[0009] Step S1, transmitting a 77 GHz frequency modulated continuous wave signal to a target scene simultaneously through multiple transmitting antennas, the transmitting antennas include TX1 and TX2, and the expression of the frequency modulated continuous wave signal is: tx1,tx2 (t) = Aexp(1j*2*pi*f0*t+k*t 2 ), where k is the slope of the frequency modulated continuous wave, f0 is the carrier frequency, t is the duration of the signal pulse, and A is the power amplitude of the transmitted signal;

[0010] Step S2, receiving echo signals, the echo signals are received by multiple receiving channels, the receiving channels process the echo signals through a mixer to generate an intermediate frequency signal, and the signals received by odd-numbered and even-numbered transmissions are distinguished by an intermediate frequency signal processor;

[0011] Step S3, signal enhancement processing, performing enhancement preprocessing on the received intermediate frequency signal, then performing Fourier transform on the enhanced intermediate frequency signal to obtain a frequency domain signal, using the CA-cfar algorithm to detect the target point position, extracting the local peak value and storing it;

[0012] Step S4, error correction, establishing a time-varying power amplitude model based on the power inconsistency during the odd-numbered and even-numbered transmissions, and correcting the signal error caused by the instability of the transmitting device;

[0013] Step S5, extracting the intermediate frequency signal of the receiving channel by Fourier transform, and using the CA-cfar algorithm to detect the target point position and peak value, and then comparing the peak position to determine whether it is a stable point;

[0014] Step S6, using multi-layer integral accumulation angle solution to decouple the received echo signal, improve the angle resolution based on the multi-layer integral accumulation method, and generate a channel decoupling signal;

[0015] Step S7, combining the results of target point detection and angle solution, accurately calculate the position and speed of the target, and output the positioning information through the data output module to complete the high-precision positioning of the target.

[0016] Optionally, when the number of transmissions of the echo signal received by multiple receiving channels is an odd number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the scene. After passing through the target scene, the expression of the signals received by all receiving channels is: Among them, i is 1, 2; for TX1 and TX2, p tx i is the target of the signal transmitted by the i-th antenna, that is, the code of all targets in the scene, The scattering intensity of the target is explained as before, Where i is the transmitting antenna number. If i=1, it means the distance from transmitting antenna 1 to target P. C is the speed of light. S r,alln It is the general term for the scene signals received by all receiving channels of the receiver. Then the odd signal is obtained and the received signal is processed by the mixer to obtain the corresponding intermediate frequency signal. Its expression is: Where, f = k*t + f0, S r中,alln It is the general term for the intermediate frequency signals of all receiving channels, and n is the code of the receiving channel.

[0017] When the transmission signal is an even number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the target scene, but unlike the odd number transmission, the phase of the TX2 signal is rotated by 180°. Therefore, the signals transmitted by TX1 and TX2 can be expressed as:

[0018] in, and is the signal strength corresponding to the transmitting antennas TX1 and TX2, and are the distances from the transmitting antenna to the target respectively. Subsequently, the received signal is processed by the mixer and converted into an intermediate frequency signal, which is expressed as: in, and These are the distance information of the signals transmitted by transmitting antenna 1 and transmitting antenna 2 to the target respectively. Finally, the even-numbered and odd-numbered transmission processes are repeated N times.

[0019] Optionally, the steps for signal enhancement processing are:

[0020] Step S301, when performing enhancement preprocessing on the received intermediate frequency signal, first, set the total number of initial value cycles N and the cycle step shift amount K to prepare initial conditions for subsequent steps;

[0021] Step S302: After entering the loop, all even-numbered and odd-numbered intermediate frequency signals S in the receiving channels are received. r中,alln (t) Shift the whole to the left by K bits to shift the signal, and then perform adjacent difference operation. The shifted signal is expressed as: Where i is the number of cycles;

[0022] Step S303: the shifted intermediate frequency signal S new_K_i(t) Perform adjacent difference operation to calculate the difference between two adjacent points to extract the change information in the signal. The adjacent difference operation formula is: new_diff =S new_K_i (tn)-S new_K_i (t-n+1), then, after completing each cycle, the S of each cycle new_diff The values ​​are accumulated and saved, and the expression of the accumulated signal is: This step accumulates the differential signals in all cycles to form a complete enhanced signal;

[0023] Step S304: accumulating the signal S in step S303 sum Perform Fourier transform to obtain the frequency domain signal S fft (t), the formula is: Among them, FFT is the Fourier transform operator, Mul Snr represents the signal-to-noise ratio enhancement factor, and lamda is the wavelength.

[0024] Optionally, in step S4, when correcting the signal error caused by the instability of the transmitting device, first, a time-varying power amplitude model error is constructed, and then the loss coefficients of odd-numbered transmissions and receptions relative to even-numbered transmissions and receptions are set to β1 and β2, and the following equation is established:

[0025]

[0026] Among them, TX1 is the signal transmitted by transmitting antenna 1 after intermediate frequency demodulation, and TX2 is the signal transmitted by transmitting antenna 2 after intermediate frequency demodulation; therefore, the error model established is:

[0027]

[0028] Optionally, when generating the channel decoupling signal in step S5, first, the intermediate frequency signals of all receiving channels are Fourier transformed, and all receiving channel signals are arranged in sequence according to the channel sequence number, and then the time dimension Fourier transform is performed, and the expression is: Then, using the CA-cfar algorithm S array (t) and S fft_n The one-dimensional matrix (t,n)n=1 is used for detection to extract the position and local peak of the target point. Then, the detected target peak information is stored in store1 and store2, recorded as bin_num and peak. Then, the point is taken out from store1 and its bin_num / N is compared in store2. If the point is within the specified range, it is considered to be a stable point; if it is not within the range, it is determined to be an unstable point.

[0029] In step S6, the amplitude attenuation coefficient of the receiving channel needs to be analyzed and processed by the channel data. According to the established error model, the error model is used to construct an overdetermined equation group about M stable points. When M≥, the equation group of the stable point is as follows: Then, the amplitude attenuation coefficients β1 and β2 are obtained by solving the above overdetermined equations. Finally, after solving the amplitude attenuation coefficients β1 and β2, the transmit signal is decoupled by the formula to obtain the corrected transmit signal expression:

[0030] Optionally, when step S7 is to improve the angular resolution by multi-layer integral accumulation, first, a multi-layer auxiliary integral network vector is constructed and the angular position of the target is set to θ\thetaθ, and a guidance vector group from the target to the array element is constructed, and its expression is: Therefore, the constructed multi-layer auxiliary integral network vector is:

[0032]

[0033] Then, a multi-layer integral network vector is used to construct a cyclic accumulation mechanism. After the construction is completed, the N elements in the nth column of the Anet network matrix are extracted, and each element performs the following operation:

[0034] S total (n,θ n ) = ∫A net (1,n)A(θ)+∫A net (2,n)A(θ)+…∫A net (N,n)A(θ)

[0035] Among them, A in the formula net (1,n)…A net (N,n) represents all row elements in the n columns of the network matrix, and n represents the nth column.

[0036] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0037] 1. The present invention can effectively eliminate the time-varying effect caused by the change of scattering amplitude. Through real-time monitoring and compensation processing of the target scattering characteristics, the accuracy output of subsequent target angle positioning is guaranteed, and the positioning deviation caused by the change of motion state is reduced. This provides technical guarantee for the reliability of the vehicle-mounted millimeter wave radar system in complex dynamic environments.

[0038] 2. Effectively improve the radar's angular resolution and accuracy through hierarchical signal processing and accumulation. Specifically, the accumulation process combines information from multiple signal channels to reduce the accuracy loss caused by the short aperture. In this way, the radar can significantly improve its angular resolution without increasing hardware costs, giving it better target separation and recognition capabilities.

[0039] 3. By performing cyclic shift and differential processing on the received intermediate frequency signal, small signal changes are accumulated and the signal-to-noise ratio of the weak target is gradually improved. This process can enhance the weak target signal and make it more obvious in the noise background. In addition, in order to further improve the recognition accuracy of noise and targets, the present invention also adopts a peak comparison method to distinguish between noise and real targets by comparing the signal peak position. This peak position-based comparison technology can accurately identify the target position and reduce the false alarm rate, especially in complex interference environments.

[0040] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0042] In the figure:

[0043] Figure 1 It is a structural diagram.

[0044] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0045] The present invention will now be described in further detail with reference to the accompanying drawings.

[0046] See also Figure 1 As shown, in this embodiment, a high-precision positioning method based on a 77 GHZ vehicle-mounted millimeter-wave radar is provided, including the following steps:

[0047] Step S1, transmitting a 77 GHz frequency modulated continuous wave signal to a target scene simultaneously through multiple transmitting antennas, the transmitting antennas include TX1 and TX2, and the expression of the frequency modulated continuous wave signal is: tx1,tx2 (t) = Aexp(1j*2*pi*f0*t+k*t 2 ), where k is the slope of the frequency modulated continuous wave, f0 is the carrier frequency, t is the duration of the signal pulse, and A is the power amplitude of the transmitted signal;

[0048] Step S2, receiving echo signals, the echo signals are received by multiple receiving channels, the receiving channels process the echo signals through a mixer to generate an intermediate frequency signal, and the signals received by odd-numbered and even-numbered transmissions are distinguished by an intermediate frequency signal processor;

[0049] Step S3, signal enhancement processing, performing enhancement preprocessing on the received intermediate frequency signal, then performing Fourier transform on the enhanced intermediate frequency signal to obtain a frequency domain signal, using the CA-cfar algorithm to detect the target point position, extracting the local peak value and storing it;

[0050] Step S4, error correction, establishing a time-varying power amplitude model based on the power inconsistency during the odd-numbered and even-numbered transmissions, and correcting the signal error caused by the instability of the transmitting device;

[0051] Step S5, extracting the intermediate frequency signal of the receiving channel by Fourier transform, and using the CA-cfar algorithm to detect the target point position and peak value, and then comparing the peak position to determine whether it is a stable point;

[0052] Step S6, using multi-layer integral accumulation angle solution to decouple the received echo signal, improve the angle resolution based on the multi-layer integral accumulation method, and generate a channel decoupling signal;

[0053] Step S7, combining the results of target point detection and angle solution, accurately calculate the position and speed of the target, and output the positioning information through the data output module to complete the high-precision positioning of the target.

[0054] In this embodiment, when the number of transmissions of the echo signal received by multiple receiving channels is an odd number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the scene. After passing through the target scene, the expression of the signals received by all receiving channels is: Among them, i is 1, 2; for TX1 and TX2, p tx i is the target of the signal transmitted by the i-th antenna, that is, the code of all targets in the scene, The scattering intensity of the target is explained as before, Where i is the transmitting antenna number. If i=1, it means the distance from transmitting antenna 1 to target P. C is the speed of light. S r,alln It is the general term for the scene signals received by all receiving channels of the receiver. Then the odd signal is obtained and the received signal is processed by the mixer to obtain the corresponding intermediate frequency signal. Its expression is: Where, f = k*t + f0, S r中,alln It is the general term for the intermediate frequency signals of all receiving channels, and n is the code of the receiving channel.

[0055] When the transmission signal is an even number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the target scene, but unlike the odd number transmission, the phase of the TX2 signal is rotated by 180°. Therefore, the signals transmitted by TX1 and TX2 can be expressed as:

[0056] in, and is the signal strength corresponding to the transmitting antennas TX1 and TX2, and are the distances from the transmitting antenna to the target respectively. Subsequently, the received signal is processed by the mixer and converted into an intermediate frequency signal, which is expressed as: in, and These are the distance information of the signals transmitted by transmitting antenna 1 and transmitting antenna 2 to the target respectively. Finally, the even-numbered and odd-numbered transmission processes are repeated N times.

[0057] In this embodiment, the steps of signal enhancement processing are as follows:

[0058] Step S301, when performing enhancement preprocessing on the received intermediate frequency signal, first, set the total number of initial value cycles N and the cycle step shift amount K to prepare initial conditions for subsequent steps;

[0059] Step S302: After entering the loop, all even-numbered and odd-numbered intermediate frequency signals S in the receiving channels are received. r中,alln (t) Shift the whole to the left by K bits to shift the signal, and then perform adjacent difference operation. The shifted signal is expressed as: Where i is the number of cycles;

[0060] Step S303: the shifted intermediate frequency signal S new_K_i (t) Perform adjacent difference operation to calculate the difference between two adjacent points to extract the change information in the signal. The adjacent difference operation formula is: new_diff =S new_K_i (tn)-S new_K_i (t-n+1), then, after completing each cycle, the S of each cycle new_diff The values ​​are accumulated and saved, and the expression of the accumulated signal is: This step accumulates the differential signals in all cycles to form a complete enhanced signal;

[0061] Step S304: accumulating the signal S in step S303 sum Perform Fourier transform to obtain the frequency domain signal S fft (t), the formula is: Among them, FFT is the Fourier transform operator, Mul Snrrepresents the signal-to-noise ratio enhancement factor, and lamda is the wavelength.

[0062] In this embodiment, when correcting the signal error caused by the instability of the transmitting device in step S4, first, a time-varying power amplitude model error is constructed, and then the loss coefficients of odd-numbered transmissions and receptions relative to even-numbered transmissions and receptions are set to β1 and β2, and the following equation is established:

[0063]

[0064] Among them, TX1 is the signal transmitted by transmitting antenna 1 after intermediate frequency demodulation, and TX2 is the signal transmitted by transmitting antenna 2 after intermediate frequency demodulation; therefore, the error model established is:

[0065]

[0066] In this embodiment, when generating the channel decoupling signal, step S5 first performs Fourier transform on the intermediate frequency signals of all receiving channels, and arranges all receiving channel signals in sequence according to the channel sequence number, and then performs Fourier transform on the time dimension, and the expression is: Then, using the CA-cfar algorithm S array (t) and S fft_n The one-dimensional matrix (t,n)n=1 is used for detection to extract the position and local peak of the target point. Then, the detected target peak information is stored in store1 and store2, recorded as bin_num and peak. Then, the point is taken out from store1 and its bin_num / N is compared in store2. If the point is within the specified range, it is considered to be a stable point; if it is not within the range, it is determined to be an unstable point.

[0067] In step S6, the amplitude attenuation coefficient of the receiving channel needs to be analyzed and processed by the channel data. According to the established error model, the error model is used to construct an overdetermined equation group about M stable points. When M≥, the equation group of the stable point is as follows: Then, the amplitude attenuation coefficients β1 and β2 are obtained by solving the above overdetermined equations. Finally, after solving the amplitude attenuation coefficients β1 and β2, the transmit signal is decoupled by the formula to obtain the corrected transmit signal expression:

[0068] In this embodiment, step S7 is to improve the angular resolution by multi-layer integral accumulation. First, a multi-layer auxiliary integral network vector is constructed and the angular position of the target is set to θ\thetaθ. The guidance vector group from the target to the array element is constructed, and its expression is: Therefore, the constructed multi-layer auxiliary integral network vector is:

[0070]

[0071] Then, a multi-layer integral network vector is used to construct a cyclic accumulation mechanism. After the construction is completed, the N elements in the nth column of the Anet network matrix are extracted, and each element performs the following operation:

[0072] S total (n,θ n ) = ∫A net (1,n)A(θ)+∫A net (2,n)A(θ)+…∫A net (N,n)A(θ)

[0073] Among them, A in the formula net (1,n)…A net (N,n) represents all row elements in the n columns of the network matrix, and n represents the nth column.

[0074] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar, characterized in that: The following steps are involved: Step S1, transmitting a 77 GHz frequency modulated continuous wave signal to a target scene simultaneously through multiple transmitting antennas, the transmitting antennas include TX1 and TX2, and the expression of the frequency modulated continuous wave signal is: S tx1,tx2 (t) = Aexp(1j*2*pi*f0*t+k*t 2 ), where k is the slope of the frequency modulated continuous wave, f0 is the carrier frequency, t is the duration of the signal pulse, and A is the power amplitude of the transmitted signal; Step S2, the echo signal is received by a plurality of receiving channels, the receiving channels process the echo signal through a mixer to generate an intermediate frequency signal, and the signals received by the odd-numbered and even-numbered transmissions are distinguished by an intermediate frequency signal processor; Step S3, performing enhancement preprocessing on the received intermediate frequency signal, then performing Fourier transform on the enhanced intermediate frequency signal to obtain a frequency domain signal, using the CA-cfar algorithm to detect the target point position, extracting the local peak value and storing it; Step S4, establishing a time-varying power amplitude model based on the power inconsistency during the odd-numbered and even-numbered transmissions, and correcting the signal error caused by the instability of the transmitting device; Step S5, extracting the intermediate frequency signal of the receiving channel by Fourier transform, and using the CA-cfar algorithm to detect the target point position and peak value, and then comparing the peak position to determine whether it is a stable point; Step S6, using multi-layer integral accumulation angle solution to decouple the received echo signal, improve the angle resolution based on the multi-layer integral accumulation method, and generate a channel decoupling signal; Step S7, combining the results of target point detection and angle solution, accurately calculate the position and speed of the target, and output the positioning information through the data output module to complete the high-precision positioning of the target.

2. According to claim 1, a high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar is characterized in that: When the number of transmissions of the echo signal received by multiple receiving channels is an odd number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the scene. After passing through the target scene, the expression of the signals received by all receiving channels is: Among them, i is 1, 2; for TX1 and TX2, p txi The target of the signal transmitted by the i-th antenna is the code of all targets in the scene, The scattering intensity of the target is explained as before, Where i is the transmitting antenna number. If i=1, it means the distance from transmitting antenna 1 to target P. C is the speed of light. S r,alln It is the general term for the scene signals received by all receiving channels of the receiver. Then the odd signal is obtained and the received signal is processed by the mixer to obtain the corresponding intermediate frequency signal. Its expression is: Where, f = k*t + f0, S r中,alln It is the general term for the intermediate frequency signals of all receiving channels, and n is the code of the receiving channel. When the transmission signal is an even number, TX1 and TX2 simultaneously transmit frequency modulated continuous wave signals to the target scene, but unlike the odd number transmission, the phase of the TX2 signal is rotated by 180°. Therefore, the signals transmitted by TX1 and TX2 can be expressed as: in, and is the signal strength corresponding to the transmitting antennas TX1 and TX2, and are the distances from the transmitting antenna to the target respectively. Subsequently, the received signal is processed by the mixer and converted into an intermediate frequency signal, which is expressed as: in, and These are the distance information of the signals transmitted by transmitting antenna 1 and transmitting antenna 2 to the target respectively. Finally, the even-numbered and odd-numbered transmission processes are repeated N times.

3. The high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar according to claim 1 is characterized in that: The steps of signal enhancement processing are: Step S301, when performing enhancement preprocessing on the received intermediate frequency signal, first, set the total number of initial value cycles N and the cycle step shift amount K to prepare initial conditions for subsequent steps; Step S302: After entering the loop, all even-numbered and odd-numbered intermediate frequency signals S in the receiving channels are received. r中,alln (t) Shift the whole to the left by K bits to shift the signal, and then perform adjacent difference operation. The shifted signal is expressed as: Where i is the number of cycles; Step S303: the shifted intermediate frequency signal S new_K_i (t) Perform adjacent difference operation to calculate the difference between two adjacent points to extract the change information in the signal. The adjacent difference operation formula is: new_diff =S new_K_i (tn)-S new_K_i (t-n+1), then, after completing each cycle, the S of each cycle new_diff The values ​​are accumulated and saved, and the expression of the accumulated signal is: This step accumulates the differential signals in all cycles to form a complete enhanced signal; Step S304: accumulating the signal S in step S303 sum Perform Fourier transform to obtain the frequency domain signal S fft (t), the formula is: Among them, FFT is the Fourier transform operator, Mul Snr represents the signal-to-noise ratio enhancement factor, and lamda is the wavelength.

4. The high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar according to claim 1 is characterized in that: When correcting the signal error caused by the instability of the transmitting device in step S4, first, a time-varying power amplitude model error is constructed, and then the loss coefficients of odd-numbered transmissions and receptions relative to even-numbered transmissions and receptions are set to β1 and β2, and the following equation is established: Among them, TX1 is the signal transmitted by transmitting antenna 1 after intermediate frequency demodulation, and TX2 is the signal transmitted by transmitting antenna 2 after intermediate frequency demodulation; therefore, the error model established is:

5. The high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar according to claim 1 is characterized in that: In step S5, when generating the channel decoupling signal, first, the intermediate frequency signals of all receiving channels are Fourier transformed, and all receiving channel signals are arranged in sequence according to the channel sequence number, and then the time dimension Fourier transform is performed, and the expression is: Then, using the CA-cfar algorithm S array (t) and S fft_n The one-dimensional matrix (t,n)n=1 is used for detection to extract the position and local peak of the target point. Then, the detected target peak information is stored in store1 and store2, recorded as bin_num and peak. Then, the point is taken out from store1 and its bin_num / N is compared in store2. If the point is within the specified range, it is considered to be a stable point; if it is not within the range, it is determined to be an unstable point.

6. The high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar according to claim 1 is characterized in that: In step S6, the amplitude attenuation coefficient of the receiving channel needs to be analyzed and processed by the channel data. According to the established error model, the error model is used to construct an overdetermined equation group about M stable points. When M≥, the equation group of the stable point is as follows: Then, the amplitude attenuation coefficients β1 and β2 are obtained by solving the above overdetermined equations. Finally, after solving the amplitude attenuation coefficients β1 and β2, the transmit signal is decoupled by the formula to obtain the corrected transmit signal expression:

7. The high-precision positioning method based on 77GHZ vehicle-mounted millimeter-wave radar according to claim 1 is characterized in that: Step S7 is to improve the angular resolution by multi-layer integration accumulation. First, a multi-layer auxiliary integration network vector is constructed and the angular position of the target is set as θ\thetaθ. The guidance vector group from the target to the array element is constructed, and its expression is: Therefore, the constructed multi-layer auxiliary integral network vector is: Then, a multi-layer integral network vector is used to construct a cyclic accumulation mechanism. After the construction is completed, the N elements in the nth column of the Anet network matrix are extracted, and each element performs the following operation: S total (n,θ n )=∫A net (1,n)A(θ)+∫A net (2,n)A(θ)+…∫A net (N,n)A(θ) Among them, A in the formula net (1,n)…A net (N,n) represents all row elements in the n columns of the network matrix, and n represents the nth column.

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