CN115902784B - Uniform acceleration motion ultra-high-speed target accumulation detection method for large-time wide-bandwidth product radar - Google Patents
Uniform acceleration motion ultra-high-speed target accumulation detection method for large-time wide-bandwidth product radar Download PDFInfo
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Abstract
The application discloses a method for detecting accumulation of a target with ultra-high speed by uniform acceleration motion of a large-time wide-bandwidth product radar, which comprises the following steps: s1, establishing a multi-pulse second-order variable-scale time domain echo model; s2, converting the second-order variable-scale time domain echo into a distance unit-pulse sequence domain, and replacing a target speed value by a rotation angle; s3, setting a parameter searching range and interval, and constructing a second-order variable-scale frequency domain pulse compressor and a second-order frequency domain generalized frequency removal equation; s4, performing scale effect removal and distance walking/Doppler walking correction compensation combined treatment; s5, performing fast Fourier transform along a slow time dimension to realize phase-coherent accumulation, and performing constant false alarm detection on the target according to a phase-coherent accumulation result. The application derives a second-order scale effect formula of the uniform acceleration motion ultra-high speed target echo for the first time, and provides a scale effect removal and distance walk/Doppler walk combined implementation method, thereby greatly improving the long-distance detection performance of the large-time wide-bandwidth product radar.
Description
Technical Field
The application belongs to the technical field of radars, and particularly relates to a method for detecting a target accumulation of uniform acceleration motion and ultra-high speed of a long-time wide-bandwidth product radar.
Background
The ultra-high speed aircraft is greatly emerging along with the high-speed development of the aerospace technology, brings great challenges to radar detection, and how to realize the detection of a high-speed target becomes a difficult problem in the field of radar signal processing. The traditional coherent accumulation detection method is mainly suitable for narrow-band detection radars. When the signal bandwidth is narrow, the movement of the target at the intra-pulse time can be ignored.
However, with the improvement of the requirements of long-distance detection and high-resolution imaging, the wide-bandwidth long-product radar is widely applied, and at the moment, the motion of the target in the pulse time cannot be ignored, so that the pulse compression and accumulation result of the traditional narrow-band coherent accumulation detection method have larger loss, namely scale effect.
In addition, the ultra-high speed target often has strong maneuvering characteristics, and the phenomenon that target energy is dispersed in different distance units and Doppler units can also occur in a coherent processing interval, so that the energy is difficult to focus, namely the problems of distance walking and Doppler walking are caused. For large-time wide-bandwidth product radar, scale effect removal and distance walk/Doppler walk correction compensation need to be realized in the radar accumulation detection process.
Up to now, studies on ultra-high-speed target coherent accumulation detection mostly consider narrowband conditions such as Moving Target Detection (MTD), generalized Radon Fourier Transform (GRFT), and wedge transform matched filter processing (KT-MFP). Specifically, MTD achieves coherent accumulation with doppler filter banks, but this approach is difficult to remove scale effects and correct compensating range/doppler migration; GRFT can extract the target energy track through the distance-speed-acceleration three-dimensional joint search and perform coherent superposition; KT-MFP is to search the distance-folding factor-acceleration to realize the second-order distance walk correction and the first-order Doppler walk compensation, so as to obtain the coherent accumulation of energy. Furthermore, there are few literature at present on large-bandwidth product radar target detection, typical methods such as the scale Radon fourier transform (SCRFT). The method mainly considers the influence of the radial speed of the target on the first-order scale effect and the first-order distance walk, and does not consider the influence of the second-order scale effect, the second-order distance walk and the Doppler walk caused by the acceleration in the actual situation.
When the large-time wide-area radar detects a uniformly accelerated moving high-speed target, a second-order scale effect, a second-order distance walk and a Doppler walk can occur. At this time, the coherent accumulation performance of the existing method is lowered, and the detection performance is significantly deteriorated. Therefore, research on a coherent accumulation detection method capable of realizing scale effect removal and distance/Doppler walk correction compensation caused by speed and acceleration under a large bandwidth product is needed.
Disclosure of Invention
The application aims to overcome the defects of the prior art, and provides a method for accumulating and detecting a high-speed target by uniformly accelerating a high-speed target by a wide-bandwidth product radar with wide bandwidth under the condition of low signal to noise ratio, wherein the method is used for searching target motion parameters (comprising a distance unit, a rotation angle and acceleration) in a combined way to effectively remove a first-order/second-order scale effect, correct a first-order/second-order distance and compensate Doppler walk.
The aim of the application is realized by the following technical scheme: the method for detecting the accumulation of the ultra-high-speed target by the uniform acceleration motion of the large-time wide-area radar comprises the following steps:
the method for detecting the accumulation of the target in the ultra-high speed of the uniform acceleration motion of the large-time wide-area radar is characterized by comprising the following steps of:
s1, establishing a second-order variable-scale motion characteristic equation, constructing a second-order variable-scale time domain echo signal model, and acquiring a multi-pulse second-order variable-scale time domain echo signal based on a large-time wide-product radar emission signal form;
s2, performing variable substitution, namely converting the multi-pulse second-order variable-scale time domain echo signal from a fast time domain to a slow time domain to a distance unit-pulse sequence domain, and then replacing a radial velocity value with a rotation angle;
s3, setting a rotation angle, acceleration and a search range and interval of a distance unit, and constructing a second-order variable-scale frequency domain pulse compressor and a second-order frequency domain generalized frequency removal equation;
s4, performing scale effect removal and distance walk/Doppler walk correction compensation combined treatment: transforming the echo signal from a time domain to a distance frequency domain by utilizing distance-to-fast Fourier transform, approximating the echo signal to obtain an expression of a frequency domain echo based on a resident phase theorem, multiplying the frequency domain echo signal with a second-order variable-scale pulse compressor and a second-order frequency domain generalized frequency-removing equation in sequence, and then performing distance-domain inverse fast Fourier transform to obtain the time domain echo signal; finally, rotating the position coordinates of each data of the time echo signals, namely substituting each coordinate into a coordinate rotation formula corresponding to the search rotation angle; when the rotation angle, the acceleration and the search value of the distance unit are matched with the true value, the scale effect removal and the distance walk/Doppler walk correction compensation are jointly realized;
s5, performing fast Fourier transform on the corrected and compensated echo signals along the pulse sequence dimension to obtain a coherent accumulation result, then performing constant false alarm detection on the target according to the coherent accumulation result, and detecting the target when the accumulation peak value is higher than the threshold value.
In the step S1, the expression for obtaining the second-order variable-scale motion characteristic equation by using taylor series expansion approximation is:
wherein τ represents the time delay, c represents the speed of light, a 0 、a 1 and a2 Radial distance, radial velocity and radial acceleration between target and radar, t and t respectively m Respectively representing a fast time and a slow time;
the constructed second-order variable-scale time domain echo signal model is as follows:
wherein ,η0 Representing the complex amplitude of the echo,is a second order variable scale factor, T p Represents pulse width, gamma represents modulation frequency, f c Representing the radar carrier frequency.
The specific implementation method of the step S3 is as follows: setting an initial distance unit search value ρ' 0 Search range [ ρ ]' 0min ,ρ′ 0max ]The search step is set to Δρ, where ρ' 0min and ρ′0max The lower bound and the upper bound of the initial distance unit searching range are respectively; setting a search range [ phi ] of a rotation angle search value phi ]' min ,φ′ max ]The search step is set to Δφ, where φ' min and φ′max The lower and upper bounds of the rotation angle search range, respectively; setting an acceleration search value a' 2 Search range [ a ]' 2min ,a′ 2max ]The search step is set to Δa 2, wherein a′2min and a′2max The lower and upper bounds of the acceleration search range, respectively;
and constructing a second-order variable-scale frequency domain pulse compressor, and constructing a second-order frequency domain generalized de-frequency modulation equation to correct and compensate the second-order distance walk and the first-order Doppler walk caused by the acceleration.
The step S4 includes the following procedures:
s41, performing fast Fourier transform on the echo signal obtained in the S2 along the distance direction to obtain a frequency domain echo signal, and marking the frequency domain echo signal as S r (f ρ M); echo signal S in frequency domain r (f ρ M) multiplying the two-order variable-scale pulse compressor and the two-order frequency domain generalized frequency-removing equation in turn, and then along f ρ Performing inverse fast Fourier transform on the direction to obtain a time domain echo signal, which is denoted as s r,1 (ρ,m；ρ 0 ′,φ′,a′ 2 )；
S42, to echo signal S r,1 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The position coordinates of each data are rotated, namely each coordinate is substituted into a coordinate rotation formula corresponding to the search rotation angle, a new echo data matrix after coordinate rotation is obtained, and the new echo data matrix is recorded as s r,2 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Let s be r,2 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The position coordinates of any data in (p, m) are (p ', m') and the new position coordinates after rotation are (p ', m'), and the coordinate rotation formula is:
wherein fix (·) represents a rounding down operation; performing two-dimensional cubic convolution interpolation on the rotated coordinates to compensate approximation errors;
when ρ is satisfied 0 ′＝ρ 0 、φ′＝φ、a 2 ′＝a 2 When the time domain echo signal after the second order scale effect removal and the distance walk/Doppler walk correction compensation is obtained, the time domain echo signal is recorded as s r,1 (ρ′,m′)。
The specific implementation method of the step S5 is as follows: will s r,1 (ρ ', m') performing fast Fourier transform along the slow time direction to obtain a coherent accumulation result denoted as s CI (ρ′,f m′T)； wherein ,fm′T Is a slow time frequency domain variable corresponding to m'; and finally, carrying out constant false alarm detection on the target, detecting the target when the accumulated peak value is higher than the threshold value, otherwise, considering that the target is not detected.
The beneficial effects of the application are as follows: the application provides a method for detecting the accumulation of a target in a uniform acceleration motion ultra-high speed of a large-time wide bandwidth product radar, which aims at the problems of first-order/second-order scale effect and distance/Doppler walk when the large-time wide bandwidth product radar detects the target in the uniform acceleration motion ultra-high speed, effectively solves the problems by searching a distance unit, a rotation angle and acceleration in a combined way, removes the first-order/second-order scale effect, corrects and compensates the distance/Doppler walk at the same time, realizes the coherent accumulation of the target energy under the condition of low signal to noise ratio, and further improves the detection performance of the large-time wide bandwidth product radar on the target in the uniform acceleration motion ultra-high speed; the application derives a second-order scale effect formula of the uniform acceleration motion ultra-high speed target echo for the first time, and combines the two-order scale effect formulas to realize scale effect removal and distance/Doppler walk correction compensation, and all processes can be realized by utilizing fast Fourier transformation, thereby being beneficial to engineering realization.
Drawings
FIG. 1 is a flow chart of an implementation of the accumulation detection method of the present application;
FIG. 2 is a graph showing the result of the coherent integration according to the present embodiment;
FIG. 3 is a graph of GRFT phase-coherent accumulation results;
FIG. 4 is a graph of KT-MFP correlation accumulation results;
FIG. 5 is a graph of SCRFT coherent accumulation results;
FIG. 6 is a graph comparing the detection performance of the method of the present application with that of the conventional coherent accumulation detection method.
Detailed Description
The technical scheme of the application is further described below with reference to the attached drawings and specific embodiments. In the embodiment, a simulation experiment is mainly performed by using scientific calculation software Matlab R2020a to verify the detection effect.
As shown in FIG. 1, the method for detecting the target accumulation of the uniform acceleration motion and ultra-high speed of the large-time wide-bandwidth product radar comprises the following steps:
the method for detecting the accumulation of the target in the ultra-high speed of the uniform acceleration motion of the large-time wide-area radar is characterized by comprising the following steps of:
s1, establishing a second-order variable-scale motion characteristic equation, constructing a second-order variable-scale time domain echo signal model, and acquiring a multi-pulse second-order variable-scale time domain echo signal based on a large-time wide-product radar transmitting signal form (assumed to be a linear frequency modulation signal);
the expression for obtaining the second-order variable-scale motion characteristic equation by using the Taylor series expansion approximation is as follows:
wherein τ represents the time delay, c represents the speed of light, a 0 、a 1 and a2 Radial distance, radial velocity and radial acceleration between target and radar, t and t respectively m Respectively representing a fast time and a slow time;
the constructed second-order variable-scale time domain echo signal model is as follows:
wherein ,η0 Representing the complex amplitude of the echo,is a second order variable scale factor, T p Represents pulse width, gamma represents modulation frequency, f c Representing the radar carrier frequency.
In this embodiment, the system parameters used are: the initial distance unit of the target relative to the radar is 200, the radial speed of the target is 2000m/s, and the radial acceleration is 100m/s 2 The radar transmitting signal carrier frequency is 8GHz, the signal bandwidth is 200MHz, the sampling frequency is 400MHz, the pulse repetition frequency of the radar is 200Hz, the pulse duration is 1.5ms, the pulse number contained in one coherent accumulation time is 200, and the input signal-to-noise ratio before pulse pressure is-55 dB.
S2, performing variable substitution, namely converting the multi-pulse second-order variable-scale time domain echo signal from a fast time domain to a slow time domain to a distance unit-pulse sequence domain, and then replacing a radial velocity value with a rotation angle;
the specific implementation method comprises the following steps: will s r (t,t n ) Variables t and t in (a) m And (3) performing variable substitution:m＝t m t, thereby obtaining a discrete echo signal denoted s r (ρ, m). Where m and ρ represent the pulse sequence and the distance unit, respectively, Δd=c/(2 f) s ) And phi represents the distance unit and the rotation angle, ρ, respectively 0 Representation and a 0 The corresponding number of distance units is set,t denotes the pulse repetition interval.
Subsequently, the radial velocity is replaced by the rotation angle:the distance unit-pulse sequence echo signal expression after variable substitution is as follows:
wherein ,is the second-order variable scale factor after the variable substitution.
S3, setting a rotation angle, acceleration and a search range and interval of a distance unit, and constructing a second-order variable-scale frequency domain pulse compressor and a second-order frequency domain generalized frequency removal equation; the specific implementation method comprises the following steps: setting an initial distance unit search value ρ 0 ' search Range [ ρ ] 0 ′ min ,ρ′ 0max ]The search step is set to Δρ, where ρ 0 ′ min and ρ0 ′ max The lower bound and the upper bound of the initial distance unit searching range are respectively; setting a search range [ phi ] of a rotation angle search value phi ]' min ,φ′ max ]The search step is set to Δφ, where φ' min and φ′max The lower and upper bounds of the rotation angle search range, respectively; setting an acceleration search value a 2 'search Range [ a ]' 2min ,a′ 2max ]The search step is set to Δa 2, wherein a2 ′ min and a2 ′ max The lower and upper bounds of the acceleration search range, respectively;
constructing a second-order variable-scale frequency domain pulse compressor, wherein the expression is as follows:
wherein ,representing the search value of the second-order variable scale factor after variable substitution, f ρ Representing a distance frequency variable corresponding to ρ, B representing a signal bandwidth;
constructing a second-order frequency domain generalized de-frequency equation to correct second-order distance walk and first-order Doppler walk caused by compensation acceleration, wherein the expression is as follows:
s4, performing scale effect removal and distance walk/Doppler walk correction compensation combined treatment: transforming the echo signal from a time domain to a distance frequency domain by utilizing distance-to-fast Fourier transform, approximating the echo signal to obtain an expression of a frequency domain echo based on a resident phase theorem, multiplying the frequency domain echo signal with a second-order variable-scale pulse compressor and a second-order frequency domain generalized frequency-removing equation in sequence, and then performing distance-domain inverse fast Fourier transform to obtain the time domain echo signal; finally, rotating the position coordinates of each data of the time echo signals, namely substituting each coordinate into a coordinate rotation formula corresponding to the search rotation angle; when the rotation angle, the acceleration and the search value of the distance unit are matched with the true value, the scale effect removal and the distance walk/Doppler walk correction compensation are jointly realized; the method comprises the following steps:
s41, performing fast Fourier transform on the echo signal obtained in the S2 along the distance direction to obtain a frequency domain echo signal, and marking the frequency domain echo signal as S r (f ρ M); echo signal S in frequency domain r (f ρ M) multiplying the two-order variable-scale pulse compressor and the two-order frequency domain generalized frequency-removing equation in turn, and then along f ρ Performing inverse fast Fourier transform on the direction to obtain a time domain echo signal, which is denoted as s r,1 (ρ,m；ρ 0 ′,φ′,a′ 2 )；
S42, to echo signal S r,1 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The position coordinates of each data in (a) are rotated, i.eSubstituting each coordinate into a coordinate rotation formula corresponding to the search rotation angle to obtain a new echo data matrix after coordinate rotation, and marking the new echo data matrix as s r,2 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Let s be r,2 (ρ,m；ρ 0 ′,φ′,a′ 2 ) The position coordinates of any data in (p, m) are (p ', m') and the new position coordinates after rotation are (p ', m'), and the coordinate rotation formula is:
wherein fix (·) represents a rounding down operation; performing two-dimensional cubic convolution interpolation on the rotated coordinates to compensate approximation errors;
when ρ is satisfied 0 ′＝ρ 0 、φ′＝φ、a 2 ′＝a 2 When the time domain echo signal after the second order scale effect removal and the distance walk/Doppler walk correction compensation is obtained, the time domain echo signal is recorded as s r,1 (ρ′,m′)。
S5, performing fast Fourier transform on the corrected and compensated echo signals along the pulse sequence dimension to obtain a coherent accumulation result, then performing constant false alarm detection on the target according to the coherent accumulation result, and detecting the target when the accumulation peak value is higher than the threshold value; the specific implementation method comprises the following steps: will s r,1 (ρ ', m') performing fast Fourier transform along the slow time direction to obtain a coherent accumulation result denoted as s CI (ρ′,f m′T)； wherein ,fm′T Is a slow time frequency domain variable corresponding to m'; and finally, carrying out constant false alarm detection on the target, detecting the target when the accumulated peak value is higher than the threshold value, otherwise, considering that the target is not detected. The coherent accumulation result of the method is shown in figure 2. And finally, carrying out constant false alarm detection on the target, detecting the target when the accumulated peak value is higher than the threshold value, otherwise, considering that the target is not detected.
Fig. 3, 4 and 5 show the result of the coherent accumulation of GRFT, KT-MFP and SCRFT algorithms in the conventional method. Due to the comprehensive effects of the first-order/second-order scale effect and the distance/Doppler walk, compared with the coherent accumulation result obtained by the method, the target energy of the existing method is submerged by noise, and the coherent accumulation performance is obviously reduced; FIG. 6 shows a comparison of the detection curves of the method of the present application with the conventional GRFT, KT-MFP and SCRFT algorithms, as can be seen: the method has better constant false alarm detection performance.
Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present application and should be understood that the scope of the application is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations from the teachings of the present disclosure without departing from the spirit thereof, and such modifications and combinations remain within the scope of the present disclosure.
Claims (5)
1. The method for detecting the accumulation of the target in the ultra-high speed of the uniform acceleration motion of the large-time wide-area radar is characterized by comprising the following steps of:
s1, establishing a second-order variable-scale motion characteristic equation, constructing a second-order variable-scale time domain echo signal model, and acquiring a multi-pulse second-order variable-scale time domain echo signal based on a large-time wide-product radar emission signal form; the expression for obtaining the second-order variable-scale motion characteristic equation by using the Taylor series expansion approximation is as follows:
wherein τ represents the time delay, c represents the speed of light, a 0 、a 1 and a2 Radial distance, radial velocity and radial acceleration between target and radar, t and t respectively m Respectively representing a fast time and a slow time;
the constructed second-order variable-scale time domain echo signal model is as follows:
wherein ,η0 Representing the complex amplitude of the echo,is a second order variable scale factor, T p Represents pulse width, gamma represents modulation frequency, f c Representing radar carrier frequency;
s2, performing variable substitution, namely converting the multi-pulse second-order variable-scale time domain echo signal from a fast time domain to a slow time domain to a distance unit-pulse sequence domain, and then replacing a radial velocity value with a rotation angle;
s3, setting a rotation angle, acceleration and a search range and interval of a distance unit, and constructing a second-order variable-scale frequency domain pulse compressor and a second-order frequency domain generalized frequency removal equation;
s4, performing scale effect removal and distance walk/Doppler walk correction compensation combined treatment: transforming the echo signal from a time domain to a distance frequency domain by utilizing distance-to-fast Fourier transform, approximating the echo signal to obtain an expression of a frequency domain echo based on a resident phase theorem, multiplying the frequency domain echo signal with a second-order variable-scale pulse compressor and a second-order frequency domain generalized frequency-removing equation in sequence, and then performing distance-domain inverse fast Fourier transform to obtain the time domain echo signal; finally, rotating the position coordinates of each data of the time echo signals, namely substituting each coordinate into a coordinate rotation formula corresponding to the search rotation angle; when the rotation angle, the acceleration and the search value of the distance unit are matched with the true value, the scale effect removal and the distance walk/Doppler walk correction compensation are jointly realized;
s5, performing fast Fourier transform on the corrected and compensated echo signals along the pulse sequence dimension to obtain a coherent accumulation result, then performing constant false alarm detection on the target according to the coherent accumulation result, and detecting the target when the accumulation peak value is higher than the threshold value.
2. The method for detecting the accumulation of the target with the ultra-high speed of the uniform acceleration motion of the large-time wide-area radar according to claim 1, wherein in the step S2, the variable-substituted distance unit-pulse sequence echo signal expression is:
wherein m and ρ represent the pulse sequence and the distance unit, respectively,for the second-order variable scale factor after the variable substitution, deltad and phi respectively represent a distance unit and a rotation angle, ρ 0 Representation and a 0 The corresponding number of distance elements, T, represents the pulse repetition interval.
3. The method for detecting the accumulation of the ultra-high-speed target by the uniform acceleration motion of the large-time wide-area radar according to claim 2, wherein the specific implementation method of the step S3 is as follows: setting an initial distance unit search value ρ' 0 Is a search range of (a)The search step is set to Δρ, where ρ' 0min and ρ′0max The lower bound and the upper bound of the initial distance unit searching range are respectively; setting a search range [ phi ] of a rotation angle search value phi ]' min ,φ′ max ]The search step is set to Δφ, where φ' min and φ′max The lower and upper bounds of the rotation angle search range, respectively; setting an acceleration search value a' 2 Search range [ a ]' 2min ,a′ 2max ]The search step is set to Δa 2, wherein a′2min and a′2max The lower and upper bounds of the acceleration search range, respectively;
constructing a second-order variable-scale frequency domain pulse compressor, wherein the expression is as follows:
wherein ,representing the search value of the second-order variable scale factor after variable substitution, f ρ Representing a distance frequency variable corresponding to ρ, B representing a signal bandwidth;
constructing a second-order frequency domain generalized de-frequency equation to correct second-order distance walk and first-order Doppler walk caused by compensation acceleration, wherein the expression is as follows:
4. the method for detecting the accumulation of the ultra-high-speed target by the uniform acceleration motion of the large-time wide-area radar according to claim 3, wherein the step S4 comprises the following steps:
s41, performing fast Fourier transform on the echo signal obtained in the S2 along the distance direction to obtain a frequency domain echo signal, and marking the frequency domain echo signal as S r (f ρ M); echo signal S in frequency domain r (f ρ M) multiplying the two-order variable-scale pulse compressor and the two-order frequency domain generalized frequency-removing equation in turn, and then along f ρ Performing inverse fast Fourier transform on the direction to obtain a time domain echo signal, which is denoted as s r,1 (ρ,m；ρ′ 0 ,φ′,a′ 2 )；
S42, to echo signal S r,1 (ρ,m；ρ′ 0 ,φ′,a′ 2 ) The position coordinates of each data are rotated, namely each coordinate is substituted into a coordinate rotation formula corresponding to the search rotation angle, a new echo data matrix after coordinate rotation is obtained, and the new echo data matrix is recorded as s r,2 (ρ,m；ρ′ 0 ,φ′,a′ 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Let s be r,2 (ρ,m；ρ′ 0 ,φ′,a′ 2 ) The position coordinates of any data in (p, m) are (p ', m') and the new position coordinates after rotation are (p ', m'), and the coordinate rotation formula is:
wherein fix (·) represents a rounding down operation; performing two-dimensional cubic convolution interpolation on the rotated coordinates to compensate approximation errors;
when ρ 'is satisfied' 0 ＝ρ 0 、φ′＝φ、a′ 2 ＝a 2 When the time domain echo signal after the second order scale effect removal and the distance walk/Doppler walk correction compensation is obtained, the time domain echo signal is recorded as s r,1 (ρ′,m′)。
5. The method for detecting the accumulation of the ultra-high-speed target by the uniform acceleration motion of the large-time wide-area radar according to claim 4, wherein the specific implementation method of the step S5 is as follows: will s r,1 (ρ ', m') performing fast Fourier transform along the slow time direction to obtain a coherent accumulation result denoted as s CI (ρ′,f m′T)； wherein ,fm′T Is a slow time frequency domain variable corresponding to m'; and finally, carrying out constant false alarm detection on the target, detecting the target when the accumulated peak value is higher than the threshold value, otherwise, considering that the target is not detected.
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