CN111443335A - Method, system and device for estimating target micro-motion parameters of broadband radar and storage medium - Google Patents

Method, system and device for estimating target micro-motion parameters of broadband radar and storage medium Download PDF

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CN111443335A
CN111443335A CN202010203598.XA CN202010203598A CN111443335A CN 111443335 A CN111443335 A CN 111443335A CN 202010203598 A CN202010203598 A CN 202010203598A CN 111443335 A CN111443335 A CN 111443335A
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obtaining
target
information
phase information
curve
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CN111443335B (en
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朱楠楠
徐世友
张磊
陈曾平
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Sun Yat Sen University
National Sun Yat Sen University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—Receivers
    • G01S7/292—Extracting wanted echo-signals
    • G01S7/2923—Extracting wanted echo-signals based on data belonging to a number of consecutive radar periods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/415—Identification of targets based on measurements of movement associated with the target

Abstract

The invention discloses a method, a system, a device and a storage medium for estimating a target micro-motion parameter of a broadband radar, wherein the method comprises the following steps: acquiring an echo signal, and obtaining a high-resolution range profile of a target according to the echo signal; obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses; obtaining track information of each scattering center according to the pulse, and obtaining corresponding phase information according to the track information; acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a microspur curve of a target according to the unwrapped phase information; and obtaining a target micro-motion parameter estimation value according to the micro-distance curve. According to the invention, by acquiring the time delay information of the pulse interval of two adjacent frames, the Doppler ambiguity can be effectively solved, and the estimation precision of the target micro-motion parameter is improved. The invention can be widely applied to the technical field of radars.

Description

Method, system and device for estimating target micro-motion parameters of broadband radar and storage medium
Technical Field
The invention relates to the technical field of radars, in particular to a method, a system and a device for estimating a target micro-motion parameter of a broadband radar and a storage medium.
Background
With the increase of the bandwidth of the signal transmitted by the broadband radar, the target is expanded on the radial distance of the radar, the target spans a plurality of distance units, and the detection and identification of the distance expanded target under the broadband condition can obtain better detection and identification performance than that of the narrow-band radar. However, the broadband radar still has some problems in different applications, such as the target radial distance dimension extension and the target energy diffusion, so how to effectively accumulate the distance extension target under the noise background is the central importance of the broadband radar distance extension target detection technology. Moreover, due to the increase of the bandwidth of the radar, the radar works under the condition of relatively high carrier frequency, and in some applications, the pulse repetition frequency of a broadband radar system is low, so that the obvious micro-doppler ambiguity phenomenon is caused, and how to effectively solve the doppler ambiguity is also a big difficulty of the broadband radar technology.
The traditional method based on the envelope distance measurement has low precision which is only C/2B, if the phase distance measurement method is adopted, the distance measurement precision can reach the magnitude of half wavelength, namely lambda/2, and the distance measurement precision can be effectively improved. However, the existing phase ranging methods are basically performed under the condition that the signal-to-noise ratio is high enough, and the doppler ambiguity cannot be effectively resolved under the condition that the signal-to-noise ratio is low, so that the high-precision target micro-motion parameter estimation value cannot be obtained.
Disclosure of Invention
To solve the above technical problems, the present invention aims to: a method, a system, a device and a storage medium for estimating target micro-motion parameters of a broadband radar are provided, so that the estimation value of the target micro-motion parameters can be efficiently and accurately obtained under the condition of low signal-to-noise ratio.
The technical scheme adopted by the invention on one hand is as follows:
a method for estimating a target micro-motion parameter of a broadband radar comprises the following steps:
acquiring an echo signal, and obtaining a high-resolution range profile of a target according to the echo signal;
obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses;
obtaining track information of each scattering center according to the pulse, and obtaining corresponding phase information according to the track information;
acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a microspur curve of a target according to the unwrapped phase information;
and obtaining a target micro-motion parameter estimation value according to the micro-distance curve.
Further, the step of obtaining the echo signal and obtaining the high-resolution range profile of the target according to the echo signal specifically includes:
and acquiring an echo signal, performing pulse compression processing on the echo signal, and obtaining a high-resolution range profile of the target according to the echo signal after the pulse compression processing.
Further, the step of obtaining the track information of each scattering center according to the pulse and obtaining the corresponding phase information according to the track information includes:
estimating to obtain a target state sequence according to the pulse and the probability density function of the target state sequence;
obtaining the flight path information of each scattering center according to the target state sequence and a preset constant false alarm probability detection threshold;
and obtaining corresponding phase information according to the track information and the echo signal.
Further, the step of obtaining time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a microspur curve of a target according to the unwrapped phase information includes:
performing autocorrelation operation on the pulse to obtain time delay information of the interval of two adjacent frames of pulses;
acquiring unwrapped phase information according to the time delay information and the phase information;
and obtaining a microspur curve of the target by utilizing a phase ranging principle according to the phase information after the unwrapping.
Further, the target inching parameter estimation value comprises a precession frequency estimation value, a precession angle estimation value, a half cone angle estimation value, a bus length estimation value, a cone height estimation value and a bottom surface radius estimation value.
Further, the obtaining process of the precession frequency estimated value and the precession angle estimated value is as follows:
carrying out Fourier transform on the microspur curve to obtain frequency domain information of the microspur curve;
obtaining a precession frequency estimation value according to the frequency domain information;
and obtaining a precession angle estimated value according to the precession frequency estimated value.
Further, the process for obtaining the half cone angle estimated value, the bus length estimated value, the cone height estimated value and the bottom surface radius estimated value is as follows:
obtaining the distance difference of two scattering centers observed at each time in the microspur curve;
calculating the projection vector of the distance between the two scattering centers on the sight line of the broadband radar;
obtaining a half cone angle estimated value according to the distance difference and the projection vector;
and obtaining a bus length estimated value, a cone height estimated value and a bottom surface radius estimated value according to the half cone angle estimated value.
The technical scheme adopted by the invention on one hand is as follows:
a wideband radar target micro-motion parameter estimation system, comprising:
the high-resolution range profile module is used for acquiring echo signals and obtaining a high-resolution range profile of the target according to the echo signals;
the up-sampling module is used for obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses;
the phase information module is used for obtaining track information of each scattering center according to the pulse and obtaining corresponding phase information according to the track information;
the microspur curve generating module is used for acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a target microspur curve according to the unwrapped phase information;
and the parameter estimation module is used for obtaining a target micro-motion parameter estimation value according to the macro curve.
The technical scheme adopted by the other aspect of the invention is as follows:
a broadband radar target micro-motion parameter estimation device is characterized by comprising:
at least one processor;
at least one memory for storing at least one program;
when executed by the at least one processor, cause the at least one processor to implement the wideband radar target micro-motion parameter estimation method.
The technical scheme adopted by the other aspect of the invention is as follows: a storage medium having stored therein processor-executable instructions, wherein the processor-executable instructions, when executed by a processor, are configured to perform the wideband radar target micro-motion parameter estimation method.
The invention has the beneficial effects that: according to the method, the system, the device and the storage medium for estimating the target micro-motion parameters of the broadband radar, each scattering center is subjected to up-sampling processing to obtain a plurality of frames of pulses, track information of each scattering center is obtained according to the pulses, corresponding phase information is obtained according to the track information, extraction of a macro curve under the condition of low data rate is adapted, and accumulation detection of high-speed weak targets is realized; by acquiring the time delay information of the interval of two adjacent frames of pulses, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a microspur curve of a target according to the unwrapped phase information, the Doppler ambiguity can be effectively solved, and the estimation precision of the target micro-motion parameters is improved.
Drawings
FIG. 1 is a schematic flow chart of a method for estimating a target micro-motion parameter of a broadband radar according to an embodiment of the present invention;
FIG. 2 is a block diagram of a wideband radar target micro-motion parameter estimation system according to an embodiment of the present invention;
FIG. 3 is a block diagram of a wideband radar target micro-motion parameter estimation apparatus according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an overall concept provided by an embodiment of the present invention;
FIG. 5 is a schematic diagram of a high-resolution range profile of a target echo according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of track information provided by an embodiment of the present invention;
FIG. 7 is a schematic diagram of phase information after unwrapping according to an embodiment of the present invention;
fig. 8 is a comparison graph of the estimated value and the true value of the macro curve of the simulation experiment provided by the embodiment of the present invention:
FIG. 9 is a schematic diagram of cone height estimation error as a function of signal-to-noise ratio for a simulation experiment according to an embodiment of the present invention;
fig. 10 is a schematic diagram of variation of a bottom radius estimation error with a signal-to-noise ratio in a simulation experiment according to an embodiment of the present invention.
Reference numerals:
201. a high resolution range profile module; 202. an up-sampling module; 203. a phase information module; 204. a microspur curve generating module; 205. a parameter estimation module; 301. a processor; 302. a memory; 401. a microspur curve estimation value; 402. true value of the microspur curve.
Detailed Description
The invention is described in further detail below with reference to the figures and the specific embodiments. The step numbers in the following embodiments are provided only for convenience of illustration, the order between the steps is not limited at all, and the execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.
Referring to fig. 1, the invention provides a method for estimating a target micro-motion parameter of a broadband radar, which comprises the following steps:
s101, acquiring an echo signal, and obtaining a high-resolution range profile of a target according to the echo signal;
specifically, an echo signal is acquired, pulse compression processing is performed on the echo signal, and a high-resolution range profile of the target is obtained according to the echo signal after the pulse compression processing.
In the embodiment of the invention, the transmitted signal of the broadband radar ballistic target observation task
Figure BDA0002420195350000041
Can be expressed as:
Figure BDA0002420195350000042
wherein the content of the first and second substances,
Figure BDA0002420195350000043
Figure BDA0002420195350000044
indicating fast time, TrDenotes the pulse repetition interval, tm＝mTrIndicating slow time, TpRepresenting the pulse duration, fcRepresenting the carrier frequency of the signal and k the chirp rate.
Echo signal received by broadband radar
Figure BDA0002420195350000045
Can be expressed as:
Figure BDA0002420195350000051
wherein A isr,iRepresents the scattering coefficient of the ith scattering center, ri(tm) Denotes the micro distance of the ith scattering center, λ ═ c/fcRepresenting the carrier wavelength of the signal, c the speed of light, N the number of target equivalent scattering centers, p1,p2,p3Representing the equivalent scattering point of a moving object, nr(tm) Representing echo signal noise.
If the signal is transmitted as a single frequency pulse, the narrower the pulse, the wider the signal band. However, it is difficult to transmit a narrow pulse with a high peak power, so the embodiment of the present invention uses a wide bandwidth signal, and after receiving the wide bandwidth signal, the narrow pulse is obtained by pulse compression processing.
Performing pulse compression processing on the echo signal, and obtaining a high-resolution range profile of the target according to the echo signal after the pulse compression processing
Figure BDA0002420195350000052
Figure BDA0002420195350000053
Wherein B denotes the signal bandwidth, As,iRepresenting the amplitude of the signal after pulse compression, Av,iRepresenting the amplitude of the signal after the inclusion of a sinc function, no(tm) Representing noise after pulse compression.
S102, obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses;
FIG. 5 is a schematic diagram of a high-resolution range profile of a target echo according to an embodiment of the present invention, in which a broadband radar has a higher range resolution, so that the high-resolution range profile is obtained
Figure BDA0002420195350000054
The scattering centers can be resolved and then each scattering center is up-sampled to obtain a plurality of frames of pulses. The signal-to-noise ratio of the pulse signal can be improved through the up-sampling processing, so that the estimation of the subsequent target micro-motion parameters is more accurate.
S103, obtaining track information of each scattering center according to the pulse, and obtaining corresponding phase information according to the track information;
specifically, a target state sequence is estimated according to the pulse and the probability density function of the target state sequence; obtaining the flight path information of each scattering center according to the target state sequence and a preset constant false alarm probability detection threshold; and obtaining corresponding phase information according to the track information and the echo signal.
In the embodiment of the invention, the improved tracking algorithm before detection is adopted to obtain the track information of each scattering center, which specifically comprises the following steps:
the mth pulse echo signal x (m) in the slow time dimension can be expressed as:
Figure BDA0002420195350000061
pulse state x of the m-th pulsemIs recorded as:
Figure BDA0002420195350000062
wherein x isrm,
Figure BDA0002420195350000063
Respectively representing the position and velocity, x, of the target in the x-directionθm,
Figure BDA0002420195350000064
Representing the position and velocity of the target in the y-direction [. ]]TThe transpose of the matrix is represented,
Figure BDA0002420195350000065
a state space representing the target;
modeling target echoes as targets moving in a two-dimensional x-y plane: x is the number ofm+1＝fm(xm,nm) Wherein n ismRepresenting process noise;
combined processing of tracks X of M pulses1:MIs recorded as: x1:M＝[x1,x2,…,xM]；
Resolution Δ from the x-directionmAnd resolution Δ in the y directionθDividing the entire measuring plane into Mr×MθA resolution cell in which MrNumber of resolution elements in x-direction, MθThe number of resolution units in the y direction is represented;
m-th pulse, resolving the measured value in cell (m, theta)
Figure BDA0002420195350000066
Can be marked as:
Figure BDA0002420195350000067
wherein the content of the first and second substances,
Figure BDA0002420195350000068
representing background clutter, AmIndicating the amplitude of the target at the m-th pulse,
Figure BDA0002420195350000069
indicating the phase of the target at the m-th pulse;
the combined treatment of the M pulse records is: z1：M＝[z1,z2,…,zM]，
Wherein the content of the first and second substances,
Figure BDA00024201953500000610
measurement data representing the m-th pulse;
from the probability density function p (X) of the target state sequence1:M|Z1:M) Estimating to obtain a target state sequence
Figure BDA00024201953500000611
Namely:
Figure BDA00024201953500000612
wherein the content of the first and second substances,Trepresents a constant false alarm probability (CFAR) detection threshold,
Figure BDA00024201953500000613
a discrete space of states is represented that,
Figure BDA00024201953500000618
representing solution-maximum time correspondences
Figure BDA00024201953500000615
Calculating the value of (1);
the track information thus obtained
Figure BDA00024201953500000616
Can be expressed as:
Figure BDA00024201953500000617
the obtained phase information theta1:MCan be expressed as:
Figure BDA0002420195350000071
FIG. 6 is a schematic diagram of track information according to an embodiment of the present invention. In the improved tracking algorithm before detection, the calculation amount of the tracking algorithm before detection can be greatly reduced through the CFAR, the extraction of a microspur curve under the condition of low data rate is also adapted, and the accumulation detection of a high-speed weak target is realized.
S104, acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a target microspur curve according to the unwrapped phase information;
specifically, performing autocorrelation operation on the pulse obtained after the up-sampling processing to obtain time delay information of the interval between two adjacent frames of pulses; acquiring unwrapped phase information according to the time delay information and the phase information; and obtaining a microspur curve of the target by utilizing a phase ranging principle according to the phase information after the unwrapping.
It is known that if the exact doppler phase Ω can be extracted from the radar, we can obtain a measurement error in the order of half a wavelength. However, in practice, the radar can only provide a blurred doppler phase θ, and the relationship between the true phase and the blurred doppler phase is shown as follows:
θm＝Ωm-2kmπ+m，
wherein, thetamTo representmth echo phase, omegamIndicating the corresponding mth unambiguous phase, kmIs an integer such that 0 is not more than Ωm-2kmπ+m≤2π,mIndicating an unambiguous doppler measurement error.
The change in unambiguous phase between (m +1) th and mth is defined as Dm＝Ωm+1-ΩmThen the corresponding change in the blurred doppler phase can be expressed as:
dm＝θm+1-θm
＝Ωm+1-2km+1π+m+1-Ωm+2kmπ-m
＝Dm-2(km+1-km)π+m+1-m
＝Dm-2Nmπ+m+1-m
＝Dm-2Nmπ
wherein N ism＝km+1-km,θmAnd thetam+1Can be obtained from the above step S103.
The unambiguous phase difference D between mth and (m +1) th can be further obtained from the above formulam＝dm+2πNmThereby obtaining the winding number Nm。
The similarity between two signals is measured by a correlation coefficient, and applying a cross-correlation between the mth and (m +1) th echo signal pulses yields how many units the signal spans:
xcorr[x(m),x(m+1)]＝fix(ΔNstep) Wherein, fix (Δ N)step) Representing the spanning distance unit.
Then it is possible to obtain:
Figure BDA0002420195350000081
where λ represents the radar carrier wavelength and Δ x represents the resolution in the fast time direction. The up-sampling process in step S102 can ensure a large resolution in the fast time direction, thereby ensuring the accuracy of the measurement.
Obtaining unwrapped phase information
Figure BDA0002420195350000082
Figure BDA0002420195350000083
Wherein m is more than or equal to 1 and less than or equal to n-1.
Fig. 7 is a schematic diagram of phase information after unwrapping according to an embodiment of the present invention.
The microspur curve R thus obtainednCan be expressed as:
Figure BDA0002420195350000084
s105, obtaining a target micro-motion parameter estimation value according to the macro curve;
specifically, the target inching parameter estimation value comprises a precession frequency estimation value, a precession angle estimation value, a half cone angle estimation value, a bus length estimation value, a cone height estimation value and a bottom surface radius estimation value.
The precession frequency estimate
Figure BDA0002420195350000085
And precession angle estimate
Figure BDA0002420195350000086
The obtaining process is as follows: carrying out Fourier transform on the microspur curve to obtain frequency domain information of the microspur curve; obtaining a precession frequency estimation value according to the frequency domain information; and obtaining a precession angle estimated value according to the precession frequency estimated value.
In the embodiment of the invention, according to the microspur curve R, Fourier transform is carried out on the microspur curve R to obtain frequency domain information of the microspur curve R: fz 10lgFFT-1L FFT (R (t)) |. Because the high-frequency components in the frequency spectrum are only generated by the superposition of sine functions and are not influenced by other components, the precession frequency can be obtained by selecting the position information of the frequency points of the high-frequency components;
the frequency of the main peak frequency point can be expressed as: f < { F | F >3dB } >, wherein F is an estimated instantaneous microspur curve spectrum, and < · > represents the frequency of the corresponding position of a peak point with the peak height meeting the condition in an operator, and the frequency of a frequency point with the peak value larger than 3dB in the microspur curve spectrum is taken as the value of F in the embodiment of the invention;
obtaining an estimate of precession frequency
Figure BDA0002420195350000087
Comprises the following steps:
Figure BDA0002420195350000088
because the target physical parameter information is coupled in the amplitude term of the instantaneous microspur curve, the estimation difficulty is increased when estimating the micromotion parameter. Before estimation, the embodiment of the invention carries out normalization processing on the obtained instantaneous microspur curve, eliminates the influence of an amplitude factor, only influences the frequency spectrum amplitude of the instantaneous microspur curve by the precession angle, and estimates the precession angle by taking the precession frequency value obtained by estimation as known information. From the above, the error interference on the high-frequency components in the frequency spectrum is the least, so the high-frequency points are selected, the precession angle and the maximum swing angle are taken as parameters, the parameter estimation problem is converted into the optimization problem, and the following two-dimensional search is performed to obtain the precession angle estimation value
Figure BDA0002420195350000091
Figure BDA0002420195350000092
Wherein R isi(t) represents the scattering center instantaneous microspur curve, FiWhich represents the frequency spectrum of a theoretical curve,
Figure BDA0002420195350000093
indicating β value operations for solving min.
The half cone angle estimate
Figure BDA0002420195350000094
Busbar length estimate
Figure BDA0002420195350000095
Cone height estimation
Figure BDA0002420195350000096
And bottom surface radius estimate
Figure BDA0002420195350000097
The obtaining process is as follows: obtaining the distance difference of two scattering centers observed at each time in the microspur curve; calculating the projection vector of the distance between the two scattering centers on the sight line of the broadband radar; obtaining a half cone angle estimated value according to the distance difference and the projection vector; and obtaining a bus length estimated value, a cone height estimated value and a bottom surface radius estimated value according to the half cone angle estimated value.
In the embodiment of the invention, the distance ξ between the top and the bottom of the cone is recorded as ξ ═ R1-R3Hcos γ (t) -rsin γ (t), where H denotes cone height and r denotes base radius;
known bus bar length
Figure BDA0002420195350000098
Half cone angle
Figure BDA0002420195350000099
Then the maximum value ξ of ξ may be setmaxAnd minimum value ξminRespectively expressed as:
Figure BDA00024201953500000910
wherein α represents the cone target pitch angle and β represents the cone target precession angle;
derived is:
Figure BDA00024201953500000911
meanwhile, the estimated value of the half cone angle can be obtained
Figure BDA00024201953500000912
Comprises the following steps:
Figure BDA00024201953500000913
wherein the content of the first and second substances,
Figure BDA00024201953500000914
Figure BDA00024201953500000915
representing the distance difference of two scattering centers observed at each moment in the estimated curve sequence, | · |. the luminance1The expression is given in the 1-norm,
Figure BDA00024201953500000916
indicating solution-min correspondence
Figure BDA00024201953500000917
The value of (c) is calculated.
Based on the precession angle estimate
Figure BDA00024201953500000918
And half cone angle estimate
Figure BDA00024201953500000919
Obtaining a bus length estimate
Figure BDA00024201953500000920
Comprises the following steps:
Figure BDA00024201953500000921
according to the parameter estimation value, the cone height estimation value can be obtained
Figure BDA00024201953500000922
And bottom surface radius estimate
Figure BDA00024201953500000923
Figure BDA00024201953500000924
Fig. 4 is a schematic diagram of the overall concept of the embodiment of the present invention. According to the embodiment of the invention, a target high-resolution range profile is obtained according to an echo signal, so that scattering centers are distinguished, and each scattering center is subjected to up-sampling treatment to obtain pulses; accumulating the scattering center of the broadband distance target by an improved pre-detection tracking algorithm to obtain track position information and returning the track position information to echo data to obtain track Doppler phase information; meanwhile, Doppler ambiguity is resolved through autocorrelation operation to obtain real phase information, and then a microspur curve is obtained according to a phase ranging principle, so that parameter estimation is carried out. The embodiment of the invention does not need sub-aperture envelope error correction processing, can perform high-order expansion on the local microspur curve to adapt to the extraction of the microspur curve under the condition of low data rate, and has the advantages of high precision and high calculation efficiency.
The method steps of the present invention are explained above, and the effect of the present invention is further explained by combining with simulation experiments.
The cone target simulation parameters of the experiment are as follows:
TABLE 1 Cone target parameters
Height H of cone 0.96m
Distance h from center of mass to top surface 0.64m
Radius of the bottom surface r 0.25m
Spin frequency fs 4Hz
Cone-shaped screwFrequency fz 2Hz
Precession angle β 10°
The experimental broadband radar transmitting signal is a linear frequency modulation signal, and the parameters are as follows:
TABLE 2 Primary parameters of the Radar System
Carrier frequency fc 10GHz
Bandwidth B 2GHZ
Pulse width tp 100μs
Pulse repetition period prf 1000Hz
Residence time T 1s
Firstly, setting parameters according to the parameters, obtaining a high-resolution one-dimensional range profile of a target through the steps, determining the number of scattering centers according to the number of complete curves in the range profile, and performing up-sampling processing on each scattering center; then, adopting a track-before-detection algorithm to obtain track information of each scattering center, and obtaining phase information corresponding to the track information; then phase unwrapping is carried out to obtain unwrapped phase information, and a microspur curve is obtained according to the phase ranging principle; and finally, obtaining a target micro-motion parameter estimation value according to the macro curve.
Table 3 shows the comparison between the estimated value of the target inching parameter of the present invention and the estimated value of the target inching parameter obtained by the traditional distance image envelope only under the condition of 30dB signal-to-noise ratio:
TABLE 3 comparison of target micromotion parameter estimates for 30db SNR
Figure BDA0002420195350000111
If the following equation defines the estimation error:
Figure BDA0002420195350000112
wherein a, a,
Figure BDA0002420195350000113
Representing the true value and the estimated value of the target parameter, respectively, the estimation error of each parameter can be obtained as shown in table 4:
TABLE 4 comparison of target micromotion parameter estimation errors for 30db SNR
Figure BDA0002420195350000114
Referring to fig. 8, it can be known from tables 3 and 4 that, compared to the conventional method of estimating only the distance image envelope parameter, the estimated value of the target micro-motion parameter obtained by the present invention is closer to the true value, and thus, each parameter of the pyramidal target can be estimated more accurately.
In order to fully verify the anti-noise performance of the method, under the condition that other conditions are not changed, the signal-to-noise ratio is changed, the estimation errors of the target cone height and the bottom surface radius are shown in figures 9 and 10, and under the condition that the signal-to-noise ratio is higher than 7db, the parameter estimation errors do not fluctuate too much, so that the method has certain anti-noise performance.
Referring to fig. 2, the present invention further provides a system for estimating a target micro-motion parameter of a broadband radar, comprising:
the high-resolution range profile module 201 is configured to acquire an echo signal and obtain a high-resolution range profile of a target according to the echo signal;
the up-sampling module 202 is configured to obtain a plurality of scattering centers according to the high-resolution range profile, and perform up-sampling processing on each scattering center to obtain a plurality of frame pulses;
the phase information module 203 is configured to obtain track information of each scattering center according to the pulse, and obtain corresponding phase information according to the track information;
the microspur curve generating module 204 is configured to obtain time delay information of an interval between two adjacent frames of pulses, perform phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtain a target microspur curve according to the unwrapped phase information;
and the parameter estimation module 205 is configured to obtain an estimated value of the target micro-motion parameter according to the macro curve.
The contents in the above method embodiments are all applicable to the present system embodiment, the functions specifically implemented by the present system embodiment are the same as those in the above method embodiment, and the beneficial effects achieved by the present system embodiment are also the same as those achieved by the above method embodiment.
Referring to fig. 3, the present invention further provides a broadband radar target micro-motion parameter estimation apparatus, including:
at least one processor 301;
at least one memory 302 for storing at least one program;
when executed by the at least one processor 301, causes the at least one processor 301 to implement the wideband radar target jiggle parameter estimation method.
The contents in the above method embodiments are all applicable to the present apparatus embodiment, the functions specifically implemented by the present apparatus embodiment are the same as those in the above method embodiments, and the advantageous effects achieved by the present apparatus embodiment are also the same as those achieved by the above method embodiments.
Furthermore, a storage medium is provided in which processor-executable instructions are stored, which when executed by a processor, are configured to perform the wideband radar target micro-motion parameter estimation method.
According to the method, the system, the device and the storage medium for estimating the target micro-motion parameters of the broadband radar, each scattering center is subjected to up-sampling processing to obtain a plurality of frames of pulses, track information of each scattering center is obtained according to the pulses, corresponding phase information is obtained according to the track information, extraction of a macro curve under the condition of low data rate is adapted, and accumulation detection of high-speed weak targets is realized; the time delay information of two adjacent pulse intervals is obtained, the phase information is subjected to phase unwrapping according to the time delay information to obtain unwrapped phase information, and a microspur curve of the target is obtained according to the unwrapped phase information, so that Doppler ambiguity can be effectively solved, and the estimation precision of the target micro-motion parameters is improved; according to simulation experiments, the method can achieve high ranging precision under the condition of low signal-to-noise ratio, and has high noise resistance.
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A method for estimating the target micro-motion parameters of a broadband radar is characterized by comprising the following steps:
acquiring an echo signal, and obtaining a high-resolution range profile of a target according to the echo signal;
obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses;
obtaining track information of each scattering center according to the pulse, and obtaining corresponding phase information according to the track information;
acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a microspur curve of a target according to the unwrapped phase information;
and obtaining a target micro-motion parameter estimation value according to the micro-distance curve.
2. The method for estimating the target micro-motion parameters of the broadband radar according to claim 1, wherein the step of obtaining the echo signal and obtaining the high-resolution range profile of the target according to the echo signal comprises:
and acquiring an echo signal, performing pulse compression processing on the echo signal, and obtaining a high-resolution range profile of the target according to the echo signal after the pulse compression processing.
3. The method of claim 1, wherein the step of obtaining the track information of each scattering center according to the pulse and obtaining the corresponding phase information according to the track information comprises:
estimating to obtain a target state sequence according to the pulse and the probability density function of the target state sequence;
obtaining the flight path information of each scattering center according to the target state sequence and a preset constant false alarm probability detection threshold;
and obtaining corresponding phase information according to the track information and the echo signal.
4. The method according to claim 1, wherein the step of obtaining the time delay information of the pulse interval between two adjacent frames, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining the microspur curve of the target according to the unwrapped phase information includes:
performing autocorrelation operation on the pulse to obtain time delay information of the interval of two adjacent frames of pulses;
acquiring unwrapped phase information according to the time delay information and the phase information;
and obtaining a microspur curve of the target by utilizing a phase ranging principle according to the phase information after the unwrapping.
5. The method according to claim 1, wherein the target micro-motion parameter estimation value comprises a precession frequency estimation value, a precession angle estimation value, a half cone angle estimation value, a generatrix length estimation value, a cone height estimation value and a bottom radius estimation value.
6. The method for estimating the target micro-motion parameters of the broadband radar as claimed in claim 5, wherein the precession frequency estimation value and the precession angle estimation value are obtained by:
carrying out Fourier transform on the microspur curve to obtain frequency domain information of the microspur curve;
obtaining a precession frequency estimation value according to the frequency domain information;
and obtaining a precession angle estimated value according to the precession frequency estimated value.
7. The method for estimating the micro-motion parameters of the broadband radar target according to claim 5, wherein the estimated values of the half cone angle, the bus length, the cone height and the bottom radius are obtained by:
obtaining the distance difference of two scattering centers observed at each time in the microspur curve;
calculating the projection vector of the distance between the two scattering centers on the sight line of the broadband radar;
obtaining a half cone angle estimated value according to the distance difference and the projection vector;
and obtaining a bus length estimated value, a cone height estimated value and a bottom surface radius estimated value according to the half cone angle estimated value.
8. A wideband radar target micro-motion parameter estimation system, comprising:
the high-resolution range profile module is used for acquiring echo signals and obtaining a high-resolution range profile of the target according to the echo signals;
the up-sampling module is used for obtaining a plurality of scattering centers according to the high-resolution range profile, and performing up-sampling processing on each scattering center to obtain a plurality of frames of pulses;
the phase information module is used for obtaining track information of each scattering center according to the pulse and obtaining corresponding phase information according to the track information;
the microspur curve generating module is used for acquiring time delay information of two adjacent pulse intervals, performing phase unwrapping on the phase information according to the time delay information to obtain unwrapped phase information, and obtaining a target microspur curve according to the unwrapped phase information;
and the parameter estimation module is used for obtaining a target micro-motion parameter estimation value according to the macro curve.
9. A broadband radar target micro-motion parameter estimation device is characterized by comprising:
at least one processor;
at least one memory for storing at least one program;
when executed by the at least one processor, cause the at least one processor to implement a wideband radar target micro-motion parameter estimation method as recited in any one of claims 1-7.
10. A storage medium having stored therein processor-executable instructions, which when executed by a processor, are configured to perform a wideband radar target micro-motion parameter estimation method as claimed in any one of claims 1 to 7.
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