A pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model

Abstract

The application belongs to the technical field of short-range radar signal processing, and provides a pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model. The application simulates and realizes the working process of the pulse Doppler short-range radar under the condition that a short-range body target is locally irradiated by a radar, and uses a multi-scattering point structure to approximately construct a body target scattering source model capable of generating a return signal. The return signal of the part of the rigid body target irradiated by the transmitted signal is calculated, the return signals in the same range gate are superimposed to form the overall return signal of the body target, the return signal containing noise is demodulated and filtered, and then the frequency domain constant false alarm detection and the time domain threshold detection are used for target detection, so that the target starting point information is obtained. The technical scheme provided by the application can guarantee the influence of the target surface details on the effective return signal amplitude, and can also consider the calculation efficiency of the short-range radar signal simulation and the target starting point information.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of short-range radar signal processing, and particularly relates to a pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model. BACKGROUND

[0002] The millimeter wave short-range radar detector is a detector working with electromagnetic waves with wavelengths between 1-10 mm, and belongs to a short wave (high frequency) band radar system, which has good short-range characteristics and is suitable for short-range target detection.

[0003] The action distance between the detector and the target in the short-range detection environment can be comparable to the geometric size of the target itself, at which time the reflected target cannot be regarded as a point target when calculating the target echo, and the reflected target should be regarded as a volume target for operation and processing. In the process of radar detector echo signal processing based on the volume target, the surface of the three-dimensional volume target is usually divided into multiple two-dimensional surface elements, and then the target echo is calculated, and finally the echo contributions of each region are integrated to obtain the total echo signal of the three-dimensional volume target.

[0004] The size of each surface element should be small enough to capture the details of the target surface, but the subsequent calculation complexity and storage space requirements should also be considered when dividing the surface elements. Smaller surface element size means that more region units are needed to cover the entire target surface, which will significantly increase the calculation amount of the target echo signal calculation, thereby affecting the calculation efficiency of the millimeter wave short-range radar detector start point simulation calculation.

[0005] In view of the above problems, it is necessary to consider simplifying a large number of grids of the volume target in the side-looking short-range target detector irradiation area into a plurality of scattering points, constructing a multi-scattering point model of the volume target, improving the calculation efficiency of the short-range detector start point simulation, while preserving the influence of the details of the volume target surface on the echo signal amplitude, and ensuring the accuracy of the start point simulation. SUMMARY

[0006] The present application aims to solve the problems raised in the background art, and proposes a pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model.

[0007] In order to achieve the purpose of the present application, a pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model is disclosed, comprising the following steps:

[0008] Step S1, importing a target model, defining simulation short-range detector transmission signal characteristic parameters, detector and target intersection parameters and pulse Doppler signal model, recording the detector and target intersection parameters and transmission signal carrier frequency into a multi-scattering point data file;

[0009] Step S2, radar transmitting signal simulation is performed according to a pulse Doppler short-range radar transmitting signal simulation model;

[0010] Step S3, the number of scattering points is set, at each time, a multi-scattering point model of the target is constructed according to the position information of each facet of the imported target model, and the position vector of each scattering point is recorded;

[0011] Step S4, the RCS values of each facet generating the same scattering point at each time are accumulated to obtain the total RCS value of the scattering point, and the characteristic data of each scattering point is recorded in the multi-scattering point data file under the condition that the detector and the target intersection condition are unchanged at each time;

[0012] Step S5, the simulation radar signal characteristic parameters and the missile-target intersection parameters are reserved, each type of simulation gain parameter, transmitting pulse width, receiving-transmitting interval, pulse Doppler signal processing model and each signal processing model parameter are re-set, and the multi-scattering point data file generated in the above steps is read;

[0013] Step S6, the echo signal received by the receiver is often accompanied by interference, and the interference signal simulation is implemented by using the suppression type interference;

[0014] Step S7, under the new gain condition and signal processing model, the echo signal value contributed by different scattering points at each time is calculated by the echo signal simulation mathematical model, the interference is added to the echo value at each time, and the effective echo contribution of each scattering point within the range gate is accumulated to complete the echo signal simulation of the body target;

[0015] Step S8, the effective echo signal is mixed with the local signal, and the Doppler signal carrying target information is obtained after filtering processing;

[0016] Step S9, the time domain threshold detection and the frequency domain constant false alarm detection are performed on the Doppler signal, if the target exists is detected in the time domain and the frequency domain, the short-range target detector is started, the starting point information of the target point is calculated, otherwise, the simulation step calculation is circularly executed from step S7 at the next time.

[0017] Furthermore, in steps S1 or S5, the simulated short-range radar signal characteristic parameters include: radio frequency pulse amplitude, transmitted signal carrier frequency, transmitted signal power, transmitted signal beam tilt angle, beamwidth, beam range, pulse repetition period, transmit / receive interval, random pulse position modulation duty cycle, pseudocode symbol width, pseudocode sequence length, transmitted pulse width, and received pulse width; the detector-target intersection parameters include: simulated target velocity, detector velocity, target offset relative to the detector center, target offset azimuth angle, start time to the detector plane, stop time across the detector plane, and attitude angles of the short-range radar detector and the target; the pulse Doppler signal models include: equal-width, equal-period pulse Doppler signal model, random pulse position pulse Doppler signal model, and pseudocode phase-modulated pulse Doppler signal model.

[0018] Furthermore, in step S2, the mathematical model for simulating the transmitted signal of the equal-width, equal-period pulse Doppler short-range radar is as follows:

[0019]

[0020] The mathematical model for simulating the transmitted signal of a random pulse-doppler short-range radar is as follows:

[0021]

[0022] The mathematical model for simulating the transmitted signal of a pseudo-code phase-modulated pulse Doppler short-range radar is as follows:

[0023]

[0024] In the formula, A is the radio frequency pulse amplitude; ω0 is the carrier frequency of the transmitted signal; It is a width of τ M The pulse; t is time; δ(t) is the Dirichlet function; T M N is the pulse repetition period; N is the number of pulses; N i Let T0 be a random variable uniformly distributed within [0, T0]; define T0 / T M The duty cycle is the random pulse position modulation, usually taken as 0.3-0.6; M(t) = ±1 is the bipolar code corresponding to the M sequence.

[0025] Furthermore, in step S3, the position vectors of each scattering source in the scattering point model are obtained by clustering the centroid position vectors of the surface element model according to their distance.

[0026] In step S4, the characteristic data of each scattering point includes: the RCS of each scattering point, the slant range of each scattering point, the approach velocity between each scattering point and the detector, the coordinates of each scattering point, and the farthest distance between the target irradiated unit and the near-range detector.

[0027] In the step of S5, the simulation gain parameters include: antenna system input impedance, antenna gain, peak transmit power, system loss coefficient, range gate gating loss, Doppler amplification factor and video amplification factor; and the signal processing model parameters include: received pulse width, random pulse position modulation duty cycle, pseudo code symbol width and pseudo code sequence length.

[0028] Further, in the step of S6, the simulation mathematical model of the suppressed noise amplitude modulation jamming signal is:

[0029] J(t) = (U j + u n (t))cos(ω0t)

[0030] where ω0 is the center frequency of the noise amplitude modulation signal, and its value is equal to the carrier frequency of the transmitted signal; U j represents the amplitude of the jamming signal, u n (t) is a noise with variance and mean value 0, and t is time;

[0031] In the step of S7, the simulation mathematical model of the echo signal is:

[0032]

[0033] where ω0 is the carrier frequency of the transmitted signal; is a pulse with width τ M ; t is time; δ(t) is the Dirac function; T M is the pulse repetition period; N is the number of pulses; τ i is the delay of the echo signal of the i-th scattering point relative to the transmitted signal; ω di is the Doppler angular frequency generated by the motion of the target scattering point relative to the short-range detector.

[0034] Further, the Doppler angular frequency generated by the motion of the target scattering point relative to the short-range detector is:

[0035]

[0036] where V ri is the relative motion velocity between the scattering point i and the detector; is the angle between the line of sight of the scattering point i and the detector and the relative velocity vector of the two; λ is the wavelength of the beam, where F t is the carrier frequency of the transmitted signal;

[0037] In the simulation mathematical model of the echo signal, the parameter k i is a coefficient including the RCS of the scattering point, the transmit signal power and the radar range factor, and its relationship with the power at the entrance of the receiving antenna is:

[0038]

[0039] where G is the antenna gain; λ is the wavelength of the beam; r t is the slant range of the scattering point i; P i is the transmitted signal power; R is the input impedance of the antenna system; t is the radar cross section of the scattering point i.

[0040] Further, in the step of S7, the effective echo contributions of the scattering points within the range gate are accumulated, including the following steps:

[0041] S71, the effective time range of the range gate is calculated as [t1, t2] from the current simulation pulse number, the pulse repetition period, the received pulse width, the transmitted pulse width and the transmit-receive interval;

[0042] S72, a sampling point is obtained in the effective time range of the range gate with a step t0;

[0043] S73, the delay of the echo signal of the scattering point relative to the transmitted signal is calculated according to the relative distance Ri_abs between the scattering point i and the short-range detector where C is the speed of light 3×10 8 m / s;

[0044] S74, the sampling points in the effective time range of the range gate are traversed, and the time corresponding to the sampling point number Num is times=Num×t0;

[0045] S75, if times is within the echo signal time range [t3, t4] generated by the scattering point i, it is considered that the target echo generated by the scattering point i is within the range gate range, and the echo contribution value of the scattering point is calculated according to the echo signal simulation mathematical model;

[0046] S76, the echo contribution values of the scattering points generating effective echoes are accumulated to obtain the total echo simulation signal of each sampling point.

[0047] Further, in the step of S71, the lower limit of the time t1 of the effective time range of the range gate is:

[0048] t1=NT M +Tri

[0049] where N is the simulation pulse number; T M is the pulse repetition period; Tri is the transmit-receive interval; and the upper limit of the time t2 is:

[0050] t2=t1+taot

[0051] ​​Wherein, taot is the receiving pulse width.

[0052] In the step of S75, the echo signal time range lower limit t3 generated by the scattering point i is:

[0053] t3 = NT M + delay_timei

[0054] The time lower limit t4 is:

[0055] t4 = NT M +tao0+delay_timei

[0056] In the formula, N is the simulation pulse number; T M is the pulse repetition period; tao0 is the transmitting pulse width; delay_timei is the delay of the echo signal of the scattering point i relative to the transmitting signal.

[0057] Further, in the step of S8, the filter processing is realized by a second-order low-pass filter, and the mathematical model is:

[0058]

[0059] In the formula, x0(t) is the filter output value at the current time; x i (t) is the echo signal value input to the filter at the current time; t0 is the signal sampling step; f c is the cutoff frequency; γ is the damping ratio, and the value of 0.707 is the best.

[0060] Further, in the step of S9, the time domain threshold detection specific process is: setting the time domain threshold K and the pulse detection number N1, if there are N1 continuous sample values exceeding the threshold K in the Doppler signal output by the filter, it is considered that the time domain detects the target existence;

[0061] In the step of S9, the frequency domain constant false alarm detection specific process is: setting the false alarm probability and the frequency domain continuous threshold point number N2, taking the current time as the starting point, 64 sample points are intercepted, the Fourier transform is performed on the 64 data to obtain the frequency domain amplitude frequency response waveform of the sliding window data, the single unit average constant false alarm detection is performed according to the amplitude frequency response waveform at the current time, if the target existence is detected in the continuous N2 sliding windows, it is considered that the frequency domain detects the target existence.

[0062] Compared with the prior art, the significant progress of the present application is that: 1) for the characteristics of low calculation efficiency and large number of related parameters when starting point simulation is performed on the body target by the millimeter wave short-range radar detector, a multi-scattering point target model is constructed to describe the scattering source position of the body target, and on the basis of saving the intersection parameters of the short-range detector and the target, some parameters are allowed to be changed to realize the rapid calculation of the body target starting point simulation under different gain and model conditions; 2) for the application method of the range gate in the effective echo simulation process of the body target, the method of dividing the range gate first and then calculating the echo signal value of each sampling point in the range gate is adopted, which improves the simulation efficiency of the effective echo signal compared with the method of realizing the body target echo calculation first and then determining the effective echo samples in the range gate; 3) for the characteristics of discrete saving of each waveform data in the simulation process, a second-order difference equation is used to realize the filter function, which reduces the requirement of the filter on the number of input data and overcomes the difficulty that there is no accurate mathematical model to describe the Doppler signal of the echo signal after filtering after adding the interference.

[0063] To make the function and structure of the present application clearer, the following further describes the present application in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0064] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0065] Figure 1 It is a flowchart of a pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0067] As shown in Figure 1 A pulse Doppler short-range radar signal processing simulation method based on a multi-scattering point model includes the following steps:

[0068] S1, import the target model, define the simulation radar detector signal characteristic parameters, the detector and target intersection parameters and the pulse Doppler signal model, record the detector and target intersection parameters and the transmitted signal carrier frequency into the multi-scattering point data file;

[0069] S2. Simulate the radar transmission signal based on the simulation model of the pulse Doppler short-range radar detector;

[0070] S3. Set the number of scattering points. At each moment, construct a multi-scattering point model of the target object based on the position information of each surface element of the imported target model, and record the position vector of each scattering point.

[0071] S4. The total RCS value of the scattering point is obtained by summing the RCS values ​​of each surface element that generates the same scattering point at each time. The characteristic data of each scattering point is recorded in the multi-scattering point data file under the condition that the short-range radar and the target intersection remains unchanged at each time.

[0072] S5. Retain the simulated radar signal characteristic parameters and detector-target intersection parameters, reset the various types of simulation gain parameters, transmit pulse width, transmit-receive interval, pulse Doppler signal processing model and the parameters of each signal processing model, and read the multi-scattering point data file generated in the above steps;

[0073] S6. The echo signal received by the receiver is often accompanied by interference. Taking suppression interference as an example, the interference signal simulation is realized.

[0074] S7. Under the new gain conditions and signal processing model, the echo signal value contributed by different scattering points is calculated by the echo signal simulation mathematical model at each time step. Interference is added to the echo value at each time step, and the effective echo contributions of each scattering point within the range gate are accumulated to complete the echo signal simulation of the body target.

[0075] S8. Mix the effective echo signal with the local oscillator signal, and after filtering, obtain the Doppler signal carrying the target information.

[0076] S9. Perform time-domain threshold detection and frequency-domain constant false alarm detection on the Doppler signal. If the target is detected in both the time and frequency domains, start the short-range radar detector and calculate the starting point information of the target location. Otherwise, proceed to the next moment and start the simulation steps from step (7) in sequence.

[0077] In a preferred embodiment of the present invention, in step S1 or S5, the simulated short-range radar signal characteristic parameters include: radio frequency pulse amplitude, transmitted signal carrier frequency, transmitted signal power, transmitted signal beam tilt angle, beamwidth, beam range, pulse repetition period, transmit / receive interval, random pulse position modulation duty cycle, pseudocode symbol width, pseudocode sequence length, transmitted pulse width, and received pulse width; the detector-target intersection parameters include: simulated target velocity, detector velocity, target offset relative to the detector center, target offset azimuth angle, start time to the plane where the detector is located, stop time across the detector plane, and attitude angle between the short-range radar detector and the target; the pulse Doppler signal model includes: equal-width and equal-period pulse Doppler signal model, random pulse position pulse Doppler signal model, and pseudocode phase-modulated pulse Doppler signal model.

[0078] In a preferred embodiment of the present invention, in step S2, the simulation mathematical model for the transmitted signal of the equal-width, equal-period pulse Doppler short-range radar is as follows:

[0079]

[0080] The mathematical model for simulating the transmitted signal of a random pulse-doppler short-range radar is as follows:

[0081]

[0082] The mathematical model for simulating the transmitted signal of a pseudo-code phase-modulated pulse Doppler short-range radar is as follows:

[0083]

[0084] Where A is the radio frequency pulse amplitude; ω0 is the carrier frequency of the transmitted signal; It is a width of τ M The pulse; t is time; δ(t) is the Dirichlet function; T M N is the pulse repetition period; N is the number of pulses; N i Let T0 be a random variable uniformly distributed within [0, T0]; define T0 / T M The duty cycle is the random pulse position modulation, usually taken as 0.3-0.6; M(t) = ±1 is the bipolar code corresponding to the M sequence.

[0085] In a preferred embodiment of the present invention, in step S3, the position vectors of each scattering source in the scattering point model are obtained by clustering the centroid position vectors of the surface element model according to their distance.

[0086] In a preferred embodiment of the present invention, in step S4, the characteristic data of each scattering point includes: the RCS of each scattering point, the slant range of each scattering point, the approach velocity between each scattering point and the detector, the coordinates of each scattering point, and the farthest distance between the target irradiated unit and the near-range detector.

[0087] In a preferred embodiment of the present application, in the step S5, the simulation gain parameters include: antenna system input impedance, antenna gain, peak transmit power, system loss coefficient, range gate gating loss, Doppler amplification factor and video amplification factor; and the signal processing model parameters include: received pulse width, random pulse position modulation duty cycle, pseudo code symbol width and pseudo code sequence length.

[0088] In a preferred embodiment of the present application, in the step S6, the simulation mathematical model of the suppressed noise amplitude modulation jamming signal is:

[0089] J(t) = (U j + u n (t)) cos(ω0t)

[0090] wherein ω0 is the center frequency of the noise amplitude modulation signal, and the value is equal to the carrier frequency of the transmitted signal; U j represents the amplitude of the jamming signal; u n (t) is noise with a variance of and a mean of 0; and t is time.

[0091] In a preferred embodiment of the present application, in the step S7, the simulation mathematical model of the echo signal is:

[0092]

[0093] wherein ω0 is the carrier frequency of the transmitted signal; is a pulse with a width of τ M ; t is time; δ(t) is the Dirac function; T M is the pulse repetition period; N is the number of pulses; τ i is the delay of the echo signal of the i-th scattering point relative to the transmitted signal; ω di is the Doppler angular frequency generated by the relative motion of the target scattering point to the short-range radar:

[0094]

[0095] wherein V ri is the relative motion speed between the scattering point i and the detector; is the angle between the line of sight of the scattering point i and the detector and the relative velocity vector of the two; λ is the wavelength of the beam, wherein F t is the carrier frequency of the transmitted signal; k i is a coefficient including the RCS of the scattering point, the transmit signal power, the radar range factor, and the like, and the relationship between the coefficient and the power at the entrance of the receiving antenna is:

[0096]

[0097] Wherein, G t is the antenna gain; λ is the beam wavelength; r i is the slant range of the scattering point i; P t is the transmitted signal power; R is the input impedance of the antenna system; is the radar cross section of the scattering point i.

[0098] In a preferred embodiment of the present application, in the step of S7, the effective echo contributions of the scattering points within the range gate are accumulated, including the following steps:

[0099] S71, the effective time range of the range gate is calculated as [t1, t2] from the current simulation pulse number, the pulse repetition period, the received pulse width, the transmitted pulse width and the transmit-receive interval;

[0100] S72, a sampling point is obtained in the effective time range of the range gate with a step t0;

[0101] S73, the delay of the echo signal of the scattering point relative to the transmitted signal is calculated according to the relative distance Ri_abs between the scattering point i and the short-range detector Wherein, C is the speed of light 3×10 8 m / s;

[0102] S74, the sampling points in the effective time range of the range gate are traversed, and the time corresponding to the sampling point number Num is times=Num×t0;

[0103] S75, if times is within the echo signal time range [t3, t4] generated by the scattering point i, it is considered that the target echo generated by the scattering point i is within the range gate range, and the echo contribution value of the scattering point is calculated according to the echo signal simulation mathematical model;

[0104] S76, the echo contribution values of the scattering points generating effective echoes are accumulated to obtain the total echo simulation signal of each sampling point.

[0105] In a preferred embodiment of the present application, in the step of S71, the lower limit of the time range t1 of the range gate effective time range is:

[0106] t1=NT M +Tri

[0107] Wherein, N is the simulation pulse number; T M is the pulse repetition period; Tri is the transmit-receive interval; and the upper limit of the time t2 is:

[0108] t2=t1+taot

[0109] Wherein, taot is the received pulse width. ​

[0110] In a preferred embodiment of the present application, in the step of S75, the lower limit t3 of the time range of the echo signal generated by scattering point i is:

[0111] t3 = NT M + delay_timei

[0112] The lower limit t4 of the time is:

[0113] t4 = NT M + tao0 + delay_timei

[0114] Where N is the simulation pulse number; T M is the pulse repetition period; tao0 is the transmission pulse width; delay_timei is the delay of the echo signal of scattering point i relative to the transmission signal.

[0115] In a preferred embodiment of the present application, in the step of S8, the filter processing is implemented by a second-order low-pass filter, and the mathematical model thereof is:

[0116]

[0117] Where x0(t) is the filter output value at the current time; x i (t) is the echo signal value input to the filter at the current time; t0 is the signal sampling step; f c is the cutoff frequency; and γ is the damping ratio, and the effect is best when the value is 0.707.

[0118] In a preferred embodiment of the present application, in the step of S9, the specific process of the time-domain threshold detection is as follows: setting the time-domain threshold K and the pulse detection number N1, and if there are N1 continuous sample values in the Doppler signal output by the filter that exceed the threshold K, it is considered that the time-domain detection detects the existence of the target.

[0119] In a preferred embodiment of the present application, in the step of S9, the specific process of the frequency-domain constant false alarm detection is as follows: setting the false alarm probability and the number N2 of continuous threshold-exceeding points in the frequency domain, taking 64 sample points from the current time as the starting point, performing Fourier transform on the 64 data to obtain the frequency-domain amplitude-frequency response waveform of the data in the sliding window, performing unit average constant false alarm detection according to the amplitude-frequency response waveform at the current time, and if N2 continuous sliding windows all detect the existence of the target, it is considered that the frequency-domain detection detects the existence of the target.

[0120] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0121] While the embodiments of the application have been shown and described herein, it is to be understood that the scope of the application, jointly pointed out in the appended claims, is not to be limited to the above-described embodiments but can be otherwise variously changed, modified, replaced, and altered within the principles and spirit of the present application.

Claims

1. A method for simulation of pulse Doppler short-range radar signal processing based on a multi-scatterer model, characterized in that, The method comprises the following steps: Step S1, importing a target model, defining a simulation short-range detector transmitting signal characteristic parameter, a detector and target intersection parameter and a pulse Doppler signal model, recording the detector and target intersection parameter and the transmitting signal carrier frequency into a multi-scattering point data file; Step S2, performing radar transmitting signal simulation according to a pulse Doppler short-range radar transmitting signal simulation model; Step S3, setting the number of scattering points, constructing a multi-scattering point model of the target according to the position information of each facet of the imported target model at each time, and recording the position vector of each scattering point; Step S4, accumulating the RCS values of each facet of the same scattering point at each time to obtain the total RCS value of the scattering point, and recording the characteristic data of each scattering point under the condition that the intersection condition of the detector and the target is unchanged at each time in the multi-scattering point data file; Step S5, retaining the simulation radar signal characteristic parameter and the detector and target intersection parameter, re-setting each type of simulation gain parameter, transmitting pulse width, transmitting-receiving interval, pulse Doppler signal processing model and each signal processing model parameter, and reading the multi-scattering point data file generated in the above steps; Step S6, the echo signal received by the receiver is often accompanied by interference, and the interference signal simulation is realized by using suppression interference; Step S7, under the new gain condition and signal processing model, the echo signal value contributed by different scattering points is calculated by the echo signal simulation mathematical model at each time, the interference is added to the echo value at each time, and the effective echo contribution of each scattering point within the range gate is accumulated to complete the echo signal simulation of the body target; Step S8, mixing the effective echo signal with the local signal, and obtaining the Doppler signal carrying target information after filter processing; Step S9, performing time domain threshold detection and frequency domain constant false alarm detection on the Doppler signal, if the target exists in both the time domain and the frequency domain, the short-range target detector is started, the starting point information of the target point is calculated, otherwise, the simulation steps are executed in turn starting from step S7 at the next time.

2. The method of claim 1, wherein, In the steps of S1 or S5, the simulation short-range radar signal characteristic parameter comprises: radio frequency pulse amplitude, transmitting signal carrier frequency, transmitting signal power, transmitting signal beam tilt angle, beam width, beam action distance, pulse repetition period, transmitting-receiving interval, random pulse position modulation duty cycle, pseudo code symbol width, pseudo code sequence length, transmitting pulse width and receiving pulse width; the detector and target intersection parameter comprises: simulation target speed, detector speed, target offset from the center of the detector, target offset azimuth, starting time to the plane where the detector is located, stopping time through the plane of the detector and attitude angle of the short-range radar detector and the target; and the pulse Doppler signal model comprises: equal-width equal-period pulse Doppler signal model, random pulse position pulse Doppler signal model and pseudo code phase modulation pulse Doppler signal model.

3. The method of claim 2, wherein the method is characterized by: In the step of S2, the equal-width equal-period pulse Doppler short-range radar transmitting signal simulation mathematical model is: The random pulse position pulse Doppler short-range radar transmitting signal simulation mathematical model is: The pseudo code phase modulation pulse Doppler short-range radar transmitting signal simulation mathematical model is: In the formula, A is the amplitude of the radio frequency pulse; ω0is the carrier frequency of the transmitted signal; is a pulse with width τ M ; t is time; δ(t) is the Dirac function; T M is the pulse repetition period; N is the number of pulses; N i is a random variable uniformly distributed in [0, T0]; T0 / T M is the random pulse position modulation duty cycle, usually taken as 0.3-0.6; M(t) = ±1 is the bipolar code corresponding to the M sequence.

4. The method of claim 1, wherein, In the step S3, the position vectors of the scattering sources in the scattering point model are clustered according to the distance from the position vector of the center of the surface element model; In the step S4, the characteristic data of each scattering point includes: the RCS of each scattering point, the slant range of each scattering point, the approaching velocity of each scattering point to the detector, the coordinates of each scattering point and the farthest distance between the irradiated unit of the target and the short-range detector; In the step S5, the simulation gain parameters include: the input impedance of the antenna system, the antenna gain, the peak value of the transmitting power, the system loss coefficient, the distance gate gating loss, the Doppler amplification factor and the video amplification factor; and the signal processing model parameters include: the receiving pulse width, the random pulse position modulation duty cycle, the pseudo code symbol width and the pseudo code sequence length.

5. The method of claim 1, wherein, In the step S6, the simulation mathematical model of the suppressed noise amplitude modulation jamming signal is: J(t) = (U j + u n (t)) cos(ω0t) where ω0is the center frequency of the noise amplitude modulation signal, having the same value as the carrier frequency of the transmitted signal; U j represents the amplitude of the interfering signal, u n (t) is a noise with variance and mean 0, t being time; In the step S7, the echo signal simulation mathematical model is: where ω0is the carrier frequency of the transmitted signal; is a pulse with width τ M ; t is time; δ(t) is the Dirac function; T M is the pulse repetition period; N is the number of pulses; τ i is the delay of the echo signal of the i-th scattering point relative to the transmitted signal; ω di is the Doppler angular frequency produced by the relative motion of the target scattering point with respect to the proximity detector.

6. The method of claim 5, wherein the method further comprises: The Doppler angular frequency generated by the relative motion of the target scattering point to the short-range detector is: where V ri is the relative velocity between scatterer i and the detector; is the angle between the line of sight of scatterer i and the detector and the vector of their relative velocity; λ is the wavelength of the beam, where F t is the carrier frequency of the transmitted signal; Parameter k in the mathematical model of echo signal simulation i is the coefficient including the scattering point RCS, the transmitting signal power, the radar range factor, and the like, and the relationship between the power at the entrance of the receiving antenna and the parameter k is In the formula, G t λ is the antenna gain; λ is the beam wavelength; r i P is the slant distance of the scattering point i; t R is the transmitted signal power; R is the input impedance of the antenna system. Let i be the radar cross-section of the scattering point i.

7. The method of claim 1, wherein, In the step S7, the effective echo contributions of the scattering points within the distance gate are accumulated, including the following steps: S71, the effective time range of the distance gate is calculated according to the current simulation pulse number, the pulse repetition period, the receiving pulse width, the transmitting pulse width and the transmitting-receiving interval, which is [t1, t2]; S72, acquire a sampling point within an effective time range from the door with a step t0 one sampling point; S73, calculating the delay of the echo signal of the scattering point relative to the transmitted signal from the relative distance Ri_abs between the scattering point i and the proximity detector where C is the speed of light 3 x 10 8 m / s; S74, the sampling points within the effective time range of the distance gate are traversed, and the time corresponding to the sampling point number Num is times = Num × t0; S75, if times is within the echo signal time range [t3, t4] generated by the scattering point i, it is considered that the target echo generated by the scattering point i is within the distance gate range, and the echo contribution is effective, and the echo contribution value of the scattering point is calculated according to the echo signal simulation mathematical model; S76, the total echo simulation signal of each sampling point is obtained by accumulating the echo contribution values of the scattering points generating effective echoes.

8. The method of claim 7, wherein the method is characterized by: In the step S71, the lower limit t1 of the time range of the distance gate is: t1 = NT M + Tri where N is the simulation pulse number; T M is the pulse repetition period; Tri is the transmit-receive interval; the lower time limit t2 is: t2 = t1 + taot Wherein, taot is the receiving pulse width; In the step S75, the lower limit t3 of the echo signal time range generated by the scattering point i is: t3 = NT M + delay_timei The lower limit t4 of the time is: t4 = NT M + tao0+ delay_timei where N is the number of simulated pulses; T M is the pulse repetition period; tao0is the transmitted pulse width; delay timeiis the delay of the echo signal of scatterer i relative to the transmitted signal.

9. The method of claim 1, wherein, In the step S8, the filtering process is realized by using a second-order low-pass filter, and the mathematical model is: In the formula, x0(t) is the filter output value at the current time; x i (t) is the echo signal value input to the filter at the current time; t0 is the signal sampling step; f c is the cutoff frequency; γ is the damping ratio, and the effect is best when the value is 0.

707.

10. The method of claim 1, wherein, In the step S9, the specific process of the time domain threshold detection is: setting the time domain threshold K and the pulse detection number N1, if there are N1 consecutive sample values in the Doppler signal output by the filter that exceed the threshold K, it is considered that the time domain detects the existence of the target; In the step S9, the specific process of the frequency domain constant false alarm detection is: setting the false alarm probability and the number N2 of consecutive over-threshold points in the frequency domain, taking the current time as the starting point to intercept 64 sample points, and performing Fourier transform on the 64 data to obtain the frequency domain amplitude-frequency response waveform of the data in the sliding window, and performing unit average constant false alarm detection according to the amplitude-frequency response waveform at the current time, if the target exists is detected in the continuous N2 sliding windows, it is considered that the target exists is detected in the frequency domain.

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