CN103675808B - A kind of monopulse radar seeker can not differentiate multi-target detection method - Google Patents

Abstract

The invention discloses a kind of monopulse radar seeker and can not differentiate multi-target detection method, comprise the steps:, to multiple goal modeling can not be differentiated, to set up the relation of signal vector and parameter vector; According to the parameter in institute's established model, particle assembly is adopted to describe trace information; Using the priori set of this particle assembly as particle, carry out resampling to this particle assembly, the particle obtained copies in posteriority particle assembly, and repeats this operation N _psecondary, obtain the posteriority particle assembly in k-1 moment; Calculate the weights of priori particle and normalization, and by calculating the edge posterior density under target observation amount, obtain k moment radar antenna and point to vector, the present invention is by effectively combining tracking mode information and particle filter, achieve same Distance geometry speed unit in radar beam interior to multiobject resolution characteristic, obtain and multiplely can not differentiate multiobject angle information, improve radar seeker angular tracking accuracy and degree of stability, improve the ability of anti-angle scintillations simultaneously.

Description

A kind of monopulse radar seeker can not differentiate multi-target detection method

Technical field

The present invention relates to target following technology, what particularly relate to a kind of monopulse radar seeker can not differentiate multi-target detection method.

Background technology

No matter target following technology is all be widely used in military field or civil area such as air defense, air traffic control, Air Missile defence, satellite monitoring, aerial target attack, airborne early warning, ground early warning system etc.Improve the hardware device of existing weaponry and equipment, array antenna, high-resolution radar etc. is such as adopted to significantly improve target traceability, but monopulse radar is extensively equipped in guided weapon at present, if whole updating is regenerated, huge expense will be brought, therefore do not change existing weaponry and equipment, the multi-target detection realizing target seeker is comparatively economic means.

The method of traditional single pulse radar seeker target detection mainly contains than width method (amplitude Directional Method), phase comparing method, phase-magnitude relative method three kinds.

Than in width method (amplitude Directional Method) monopulse radar, in order to determine the angular coordinate in a plane, just need formation two antenna radiation patterns overlapped mutually, and the angle that their the strong sense of center line equity departs from is respectively ± θ °.When target is when departing from θ place, equisignal direction, namely the difference of vibration receiving signal by two wave beams represents the side-play amount of the strong sense of target equity, and the symbol of amplitude difference represents the offset direction of equisignal direction relative to target.When equisignal direction overlaps with target, the amplitude receiving echoed signal by two wave beams is equal, and its difference just equals zero.

Phase comparing method the phase place of two antenna received signals is relatively determined the direction of target in a coordinate plane.In region far away, two antennas all irradiate the same space scope.Therefore, the signal reflected by point target, is actually amplitude identical, and phase place is different.According to two antennas separated receive echoed signal phase differential determine the angle of arrival.

In phase-magnitude relative method, adopt two to follow the tracks of coordinate, with than width method in a tracking coordinate, in another tracking coordinate, use phase comparing method.Except there is crosstalk item and may occur except fuzzy tracking point in the method, other are identical with than width, phase comparing method because of target noise.

Above-mentioned three kinds of methods are the target detection tracking method that traditional monopulse radar is commonly used, but these methods are restricted in detection destination number, namely can detect at most two targets, can not meet the demand of modern battlefield to weaponry far away.

The deviation angle of traditional single pulse radar is the real part that multiple angle represents, and can not the existence of resolution target or multipath its real part be out of shape, even if angle represents produce error or mistake, thus making it there is imaginary part, this imaginary part obtains easily by processing the quadrature phase portion of difference signal.Therefore, two can not the measurement that represents by the multiple angle in two recurrent intervals theoretically of the angle of resolution target, Amplitude Ratio and relative phase and obtaining, and this multiple angle method for expressing is without the need to changing antenna radiation pattern thus obtaining angle error, but the method can extract at most two by multiple matched filter can not resolution target.

Be the thorny problem solved needed for monopulse radar for multiobject test problems always, the monopulse radar being applied to military service adopts traditional ratio width mostly, than phase, or further adopt maximum likelihood method, but detect 2 targets only at most.

In addition, angle scintillations problem is one of the key factor affecting monopulse radar seeker target detection, angleonly tracking precision, when target seeker is close to target, the scattering strength of complex target different parts and the random variation of relative phase, must cause the distortion before target echo phase place random wave, the inclination of wavefront on receiving antenna bore face and random swing must cause angle error.Target angle flicker belongs to clarification of objective signal in itself, the problem that tracking radar itself cannot overcome, the angle of target property research, all sizes and wavelength comparable, there is any body target of two or more equivalent scattering center, all can produce linear glint error.

Summary of the invention

For overcoming the deficiency that above-mentioned prior art exists, what one of the present invention object was to provide a kind of monopulse radar seeker can not differentiate multi-target detection method, by tracking mode information and particle filter are effectively combined, achieve same Distance geometry speed unit in radar beam interior to multiobject resolution characteristic, obtain and multiplely can not differentiate multiobject angle information, improve radar seeker angular tracking accuracy and degree of stability, improve the ability of anti-angle scintillations simultaneously.

What another object of the present invention was to provide a kind of monopulse radar seeker can not differentiate multi-target detection method, and it can reduce the calculated amount of signal transacting, meets the requirement of monopulse radar seeker real-time performance of tracking.

For reaching above-mentioned and other object, the present invention proposes a kind of monopulse radar seeker can not differentiate multi-target detection method, comprises the steps:

Step one, to differentiating multiple goal modeling, sets up the relation of signal vector and parameter vector;

Step 2, according to the parameter in institute's established model, adopts particle assembly ${\{x_{k-1}^{j,i},w_{k-1}^{j,i}\}}_{\begin{array}{cc}j=1& i=1\end{array}}^{\begin{array}{cc}{N}_p& N_{k-1}\end{array}}$ Trace information is described, wherein, N _k-1for following the tracks of number, by k-1 recurrence decision above, N _pfor the population of every secondary tracking, state vector x comprises the motion state of target and average radar cross section, for weighting coefficient;

Step 3, using the priori set of this particle assembly as particle, carry out resampling to this particle assembly, the particle obtained copies in posteriority particle assembly, and repeats this operation N _psecondary, obtain the posteriority particle assembly in k-1 moment ${\{x_{k-1}^{j,i},w_{k-1}^{j,i}\}}_{\begin{array}{cc}j=1& i=1\end{array}}^{\begin{array}{cc}{N}_p& N_{k-1}\end{array}};$

Step 4, calculates the weights of priori particle and normalization, and by calculating the edge posterior density under target observation amount, obtaining k moment radar antenna and pointing to vector ${\hat{p}}_k={\left[\begin{array}{ccc}{\hat{r}}_k& {\hat{a}}_k& {\hat{e}}_k\end{array}\right]}^T,$ Wherein be respectively and point to distance, orientation, pitching.

Further, signal vector z=[s _id _aId _eIs _qd _aQd _eQ] ^t; Parameter vector φ ⁿ=[α ₀₁..., α _0N, η _a1..., η _aN, η _e1..., η _eN] ^t, wherein, s _i, s _qbe respectively the I-phase and Q-phase with signal; d _aI, d _aQbe respectively the I-phase and Q-phase of gun parallax signal; d _eI, d _eQbe respectively the I-phase and Q-phase of trim signal; N is for can not differentiate number of targets; α _i, η _ai, η _eibe respectively the amplitude of signal, orientation to DOA, pitching to DOA.

Further, in step one, hypothetical target is Si Weilin type, sets up the relation of signal vector and parameter vector.

Further, before step 4, range gate is adopted to divide into groups to tracing detection, often the corresponding validation matrix of group.

Further, in step 3, Bayesian model in each recurrence, is adopted to select to determine detection event.

Compared with prior art, a kind of monopulse radar seeker of the present invention can not be differentiated multi-target detection method and can not differentiate on the basis of multi-objective Model in foundation, realize differentiating multiobject detection by trace information, achieve the multi-target detection in same processing unit in radar beam, obtain multiple can not the angle information of resolution target, improve radar seeker angular tracking accuracy and degree of stability, improve the ability of anti-angle scintillations simultaneously.

Accompanying drawing explanation

Fig. 1 is the flow chart of steps that a kind of monopulse radar seeker of the present invention can not differentiate multi-target detection method.

Embodiment

Below by way of specific instantiation and accompanying drawings embodiments of the present invention, those skilled in the art can understand other advantage of the present invention and effect easily by content disclosed in the present specification.The present invention is also implemented by other different instantiation or is applied, and the every details in this instructions also can based on different viewpoints and application, carries out various modification and change not deviating under spirit of the present invention.

Fig. 1 is the flow chart of steps that a kind of monopulse radar seeker of the present invention can not differentiate multi-target detection method.As shown in Figure 1, a kind of monopulse radar seeker of the present invention can not differentiate multi-target detection method, comprises the steps:

Step 101, to differentiating multiple goal modeling.

Typical monopulse radar will adopt two independently receiving branchs to each directed coordinate plane, i.e. two branch roads in aximuthpiston, two branch roads in pitch plane, therefore the present invention is measurement for angle in 2 D, four are adopted to look side ways subpulse, then receiving end can obtain three signals, namely with signal s, gun parallax signal d _a, trim signal d _e, be expressed as:

$s=\frac{1}{2}(A+B+C+D)---\left(1\right)$

$d_a=\frac{1}{2}[(C+D)-(A+B)]---\left(2\right)$

$d_e=\frac{1}{2}[(A+C)-(B+D)]---\left(3\right)$

The output of signal after separating mediation matched filtering of three passages is above:

$s_I=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_i\cos {\mathrm{\φ}}_i+n_{\mathrm{sI}}---\left(4\right)$

$s_Q=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_i\sin {\mathrm{\φ}}_i+n_{\mathrm{sQ}}---\left(5\right)$

$d_{\mathrm{aI}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\η}}_{\mathrm{ai}}{\mathrm{\α}}_i\cos {\mathrm{\φ}}_i+n_{\mathrm{daI}}---\left(6\right)$

$d_{\mathrm{aQ}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\η}}_{\mathrm{ai}}{\mathrm{\α}}_i\sin {\mathrm{\φ}}_i+n_{\mathrm{daQ}}---\left(7\right)$

$d_{\mathrm{eI}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\η}}_{\mathrm{ei}}{\mathrm{\α}}_i\cos {\mathrm{\φ}}_i+n_{\mathrm{deI}}---\left(8\right)$

$d_{\mathrm{eQ}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\η}}_{\mathrm{ei}}{\mathrm{\α}}_i\sin {\mathrm{\φ}}_i+n_{\mathrm{deQ}}---\left(9\right)$

Wherein, s _i, s _qbe respectively the I-phase and Q-phase with signal; d _aI, d _aQbe respectively the I-phase and Q-phase of gun parallax signal; d _eI, d _eQbe respectively the I-phase and Q-phase of trim signal; N is for can not differentiate number of targets; α _i, η _ai, η _eibe respectively the amplitude of signal, orientation to DOA(DirectionofArrival, Bo Dajiao), pitching is to DOA; φ _iit is the phasing degree of i-th target; Channel noise n _sI, n _sQfor zero-mean, variance is gaussian distribution; Channel noise n _daI, n _daQ, n _deI, n _deQfor zero-mean, variance is gaussian distribution.

According to formula (4)-(9), signal vector z=[s can be obtained _id _aId _eIs _qd _aQd _eQ] ^twith parameter vector φ ⁿ=[α ₀₁..., α _0N, η _a1..., η _aN, η _e1..., η _eN] ^t.Then hypothetical target is Si Weilin (Swerling) type, thus sets up the relation of signal vector and parameter vector.

By the signal model that above-mentioned approach obtains, there is actual operability, be convenient to analyze and subsequent treatment.

Step 102, adopts particle assembly ${\{x_{k-1}^{j,i},w_{k-1}^{j,i}\}}_{\begin{array}{cc}j=1& i=1\end{array}}^{\begin{array}{cc}{N}_p& N_{k-1}\end{array}}$ (wherein, N _k-1for following the tracks of number, by k-1 recurrence decision above; N _pfor the population of every secondary tracking; State vector x comprises the motion state of target and average radar cross section; for weighting coefficient) trace information is described, this descriptor determines next residence time internal antenna and points to.

Step 103, using the priori set of this particle assembly as particle, carry out resampling to this set, the particle obtained copies in posteriority particle assembly, repeats this operation N _psecondary, obtain the posteriority particle assembly in k-1 moment ${\{x_{k-1}^{j,i},w_{k-1}^{j,i}\}}_{\begin{array}{cc}j=1& i=1\end{array}}^{\begin{array}{cc}{N}_p& N_{k-1}\end{array}}.$

Step 104, calculates the weights of priori particle and normalization.Now, by calculating the edge posterior density under target observation amount k moment radar antenna can be obtained and point to vector ${\hat{p}}_k={\left[\begin{array}{ccc}{\hat{r}}_k& {\hat{a}}_k& {\hat{e}}_k\end{array}\right]}^T$ (wherein be respectively and point to distance, orientation, pitching).

Although particle filter technology has good effect to process non-gaussian nonlinear problem, the shortcomings such as sample degeneracy, calculated amount are comparatively large, calculation of complex that it exists.In order to realize validity and the real-time of particle filter multi-target detection, the present invention adopts method for resampling in step 103, and the particle of low weighting is rejected, and the particle that those high multiplied by weight obtain has identical weight, thus weakens particle decline.Various target detection event can be obtained according to radar return, this adds increased the burden of signal transacting.Meanwhile, in order to reduce calculated amount, before step 104, service range door of the present invention divides into groups to tracing detection, often the corresponding validation matrix of group, and by validation matrix can build the difference hypothesis of likely target inspection event.In each recurrence of particle filter, adopt Bayesian model to select to determine detection event, be conducive to like this calculating multiple integral by Monte Carlo method.

For the quality can not differentiating multi-target detection method of Efficient Evaluation the present invention, the present invention utilizes Cramer-Rao lower limit (CRLB) to evaluate unbiased estimator, and the variance being unbiased estimator determines a lower limit.According to CRLB theorem, the minimum value met needed for the variance of estimated parameter of deriving, for analyzing tracking error performance.Meanwhile, the present invention utilizes Matlab to emulate the present invention, and carries out principle checking in outfield to the present invention.

Utilize can not the differentiate multi-target detection method of Matlab to the present invention to emulate, adopt and carry out with the following method testing and verify:

The first, assuming that target, two can not resolution target, three can not the performance of analytical algorithm in resolution target three kinds of situations, and utilize the CRLB derived to assess detection algorithm, draw tracking error curve;

The second, in theory maximum likelihood estimator module can only estimate two can not resolution target, and for multiple can not the estimation of resolution target helpless.In order to the performance of the algorithm that project proposes is described better, this algorithm and maximum likelihood estimator module analyze by we.This analysis existence two, three can not differentiate target conditions under carry out, draw the graph of errors of two kinds of algorithms, compare the real-time of two kinds of algorithms simultaneously;

3rd, suppose that it is distinguishable for starting three targets most, and continue with linear movement close to each other, then wherein two target Continuous coordinate turns.Within the duration, three targets start to become can not resolution target, and becoming completely until three targets can not after resolution target, and target starts lasting coordinate turn, then makes continuous linear motion.Under this scene, the tracking performance of simulation analysis algorithm;

4th, suppose currently only there is a target, then occur another one target, two target trajectories are parallel, and can not differentiate, and analyze algorithm detection perform under this scene.

On the basis of Matlab theoretical simulation, make full use of lab resources, field trial checking is carried out to algorithm.Adopt four circuit receiver to be the single-conversion double sideband receiver that four magnitude-phase characteristics are identical, the phase-locked local oscillator that four circuit receiver shares same 3GHz carries out mixing, and receiver output frequency is 20MHz, bandwidth is ± radiofrequency signal of 3MHz.First produce the high-frequency signal of 2.98GHz with E4422B type signal generator, then with horn launch antenna, this signal amplitude is shot out.Arrange three and can not differentiate multiple goal, its RCS is different, i.e. a corner reflector, spherical metal, a rectangular metal body, and target is placed in different distance according to the rule preset.Multiobject radiation signal can not be differentiated, enter receiver through antenna, utilize data collecting card to obtain raw data, finally utilize the present invention to carry out estimation that object wave reaches angle DOA.

The present invention passes through Monte Carlo simulation 25000 times, has following result:

(1) when only there is a target, and signal to noise ratio snr=20dB, detection probability is 90%, and false-alarm probability is 1%;

(2) when existence two targets, and the signal to noise ratio snr=13dB of two targets, detection probability is %92, and false-alarm probability is 1%, and the size of detection probability depends on the angle that two targets are separated;

(3) when existence three targets, and the signal to noise ratio snr=20dB of target 1, the signal to noise ratio snr=13dB of target 2 and target 3, then detection probability is 94%, and false-alarm probability is 5%.

Based on the result of Monte Carlo simulation, in field trial, three targets are respectively corner reflector, spherical metal, rectangular metal body.Test findings is basic to come to the same thing with Monte Carlo simulation, but needs particularly point out, and when signal to noise ratio (S/N ratio) is less than 13dB, and the ripple of target reaches the half beam width that angle DOA departs from antenna, and false-alarm probability can increase to some extent.

In sum, a kind of monopulse radar seeker of the present invention can not be differentiated multi-target detection method and achieve and a kind ofly can effectively carry out multiple method can not differentiating target detection, the method can make do not changing under existing weaponry and equipment configuration prerequisite, realize monopulse radar seeker to 3 and above multiobject detection, and effectively can improve anti-angle scintillations and the detectability to integrated target.

Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any those skilled in the art all without prejudice under spirit of the present invention and category, can carry out modifying to above-described embodiment and change.Therefore, the scope of the present invention, should listed by claims.

Claims (5)

1. monopulse radar seeker can not differentiate a multi-target detection method, comprises the steps:

Step one, to differentiating multiple goal modeling, sets up the relation of signal vector and parameter vector;

Step 2, according to the parameter in institute's established model, adopts particle assembly trace information is described, wherein, N _k-1for following the tracks of number, by k-1 recurrence decision above, N _pfor the population of every secondary tracking, state vector x comprises the motion state of target and average radar cross section, for weighting coefficient;

Step 3, using the priori set of this particle assembly as particle, carry out resampling to this particle assembly, the particle obtained copies in posteriority particle assembly, and repeats this operation N _psecondary, obtain the posteriority particle assembly in k-1 moment

Step 4, calculates the weights of priori particle and normalization, and by calculating the edge posterior density under target observation amount, obtaining k moment radar antenna and pointing to vector ${\hat{p}}_k={\left[\begin{array}{ccc}{\hat{r}}_k& {\hat{a}}_k& {\hat{e}}_k\end{array}\right]}^T,$ Wherein be respectively and point to distance, orientation, pitching.

2. a kind of monopulse radar seeker as claimed in claim 1 can not differentiate multi-target detection method, it is characterized in that: signal vector z=[s _id _aId _eIs _qd _aQd _eQ] ^t; Parameter vector φ ⁿ=[α ₀₁..., α _0N, η _a1..., η _aN, η _e1..., η _eN] ^t, wherein, s _i, s _qbe respectively the I-phase and Q-phase with signal; d _aI, d _aQbe respectively the I-phase and Q-phase of gun parallax signal; d _eI, d _eQbe respectively the I-phase and Q-phase of trim signal; N is for can not differentiate number of targets; α ₀₁..., α _0Nfor the amplitude of signal, η _a1..., η _aNfor the orientation of signal is to DOA, η _e1..., η _eNfor the pitching of signal is to DOA.

3. a kind of monopulse radar seeker as claimed in claim 2 can not differentiate multi-target detection method, it is characterized in that: in step one, and hypothetical target is Si Weilin type, sets up the relation of signal vector and parameter vector.

4. a kind of monopulse radar seeker as claimed in claim 3 can not differentiate multi-target detection method, it is characterized in that: before step 4, adopts range gate to divide into groups to tracing detection, often the corresponding validation matrix of group.

5. a kind of monopulse radar seeker as claimed in claim 4 can not differentiate multi-target detection method, it is characterized in that: in step 3, adopts Bayesian model to select to determine detection event in each recurrence.