CN106054165A - Distributed passive radar target detection realization method - Google Patents

Abstract

The invention discloses a distributed passive radar target detection realization method, and the method belongs to the technical field of passive radar target detection. An existing target detection method is characterized by carrying out correlation and over-threshold processing independently on each bistatic pair to finish target detection, and then, obtaining bistatic distance and Doppler information of a target through estimation and carrying out target location, which results in the problem of complex ambiguous location needing to be solved in the follow-up target exact positioning process. In order to solve the problem above, the invention introduces target location and velocity vector and constructs centralized target detection statistics, so that target positioning is realized while realizing target detection, and the problem of ambiguous target location no longer needs to be treated. Besides, the method carries out non-phase-coherent accumulation on a plurality of transmitter-receiver pairs before detection to obtain space diversity gains, thereby improving target detection probability, obtaining more-stable target detection performance and providing basis for continuous and stable tracking of the target.

Description

A kind of method realizing distributed passive radar target detection

Technical field

The invention belongs to passive radar target detection technique field, realize distributed passive radar target particularly to one The method of detection.

Background technology

Passive Radar System uses the signal of third party's radiation emission, such as FM broadcast, DAB, DVB-T, gps signal, respectively The signal that kind of mobile communication base station is launched, be irradiated target realizing the detection to aerial Small object and low flyer and Location, the most also referred to as external illuminators-based radar.In the more than ten years in past, the target detection of Passive Radar System and positioning performance one Directly steadily improving.But, from system system, disclosed Passive Radar System was mainly based upon what single-shot list was received in recent years Bistatic geometry framework, target detection performance is affected very big by geometric position and the attitudes vibration of target, and then makes it at mesh Shortcomings in mark detection stability and tracking seriality.In order to make up the gap that passive radar exists in actual applications, enter One step promotes the battle application of passive radar, Europe and many research institutions of the U.S. the most to carry out based on FM, DAB, DVB-T letter Number the research of distributed passive radar technology of MIMO system of radiation source.

The target detection process of distributed passive radar classics is to utilize each transmitter-target-receiver bistatic right, Obtain target echo signal by the region making antenna direction point to transmitter and scheduled target appearance, then calculate with reference to logical Road and the cross ambiguity function or the broad sense cross-correlation that monitor between channel receiving signal realize target detection.Due to its target detection mistake Journey receives in each bistatic transmitting and internally carries out respectively, is therefore distributed object detection.Additionally, employing MIMO Target detection and the localization process of the distributed Passive Radar System of geometry framework are undertaken in two steps, first to each bistatic Transmitter and receiver completes target detection to individually carrying out being correlated with and cross threshold processing, then utilizes the bistatic distance obtained Image of colorful Doppler estimates to obtain bistatic distance and the doppler information of target, then uses the thought of cross bearing and multi-Step Iterations to enter One step realizes being accurately positioned target.The greatest drawback of this traditional treatment method is exactly that multi-Step Iterations processes the longest, And location ambiguity problem i.e. target present in position fixing process " ghost point ", need complicated to go " ghost point " logic, by follow-up enter The process of one step is removed.In practice, owing to multiple receiver cloth stations are affected by complicated terrain environment, exist not With location ambiguity problem the most scabrous between array acceptor.

Summary of the invention

It is an object of the invention to provide a kind of method realizing distributed passive radar target detection, it is possible to be used for solving many Send out the target detection problems of distributed Passive Radar System under many receipts geometry frameworks, wherein to solve the technical problem that and include:

(1) be given under MIMO geometry framework, set up distributed passive radar direct-path signal component and target echo The implementation process of component of signal；

(2) under MIMO geometry framework, build distributed passive radar realize centralized target detection statistic and The implementation process of target detection.

A kind of method realizing distributed passive radar target detection of the present invention, comprises the following steps:

(1) set up distributed passive radar direct-path signal component and target echo signal under MIMO geometry framework to divide Amount, specific implementation process comprises the steps:

A1. build under MIMO geometry framework, the signal quilt of i-th radiation emission in distributed Passive Radar System N-th array element of jth array acceptor receives and direct-path signal component after Base-Band Processing

When A2. building target travel, in distributed Passive Radar System, the signal of i-th radiation emission is through target reflection Received by the n-th array element of jth array acceptor afterwards and target echo signal component after Base-Band Processing

A3. to the i-th j bistatic centering, what the n-th array element of jth receiver received is returned by direct wave and target Signal that is that involve receiver noise and that formCarry out quantifying sampling, use its discrete shape of delay-Doppler operator representation Formula, and provide the target echo signal after Wave beam formingWith direct wave reference signal

A4. N in distributed Passive Radar System is utilized_rThat individual array acceptor receives and N_tIndividual non-cooperation radar emission All direct waves and target echo signal that source is corresponding are sampled, the matrix s that structure is made up of direct wave and target echo signal；

(2), under MIMO geometry framework, the enforcement step of centralized target detection carried out by distributed passive radar, specifically Including following sub-step:

B1. introduce position and the velocity information of target to be detected, as object detection unit, utilize echo-signal matrix s Build the inspection of binary alternative hypothesis；

B2. the hypothesis testing built is utilized, its Generalized Logarithmic likelihood ratio of deriving, obtain the inspection of distributed passive radar target Centralized detection statistic ξ surveyed_rs；

B3. according to the actual samples of signals all in distributed Passive Radar System, target detection statistic ξ is calculated_rs, By comparing detection statistic ξ_rsWith thresholding κ_rsSize, then determine that whether target exists, complete target detection.

Preferably, each array acceptor in step (1) receives direct-path signal and target echo signal simultaneously, then Direct-path signal component and target echo signal component is respectively obtained by beamforming algorithm；

Preferably, step (1) is non-coherent between different receivers array, and different receptions during target detection Need not carry out Phase synchronization between machine array process.

Compared with the classical way of distributed passive radar target detection, the present invention is at the centralized object detector of structure Time, introduce target location and velocity so that while realizing target detection, indirectly achieve the location to target, Need not carry out extra location again and conciliate Fuzzy Processing, save positioning time；Target detection process obtains space diversity Gain, improves target detection probability, it is thus achieved that more stable target detection performance, follows the tracks of for realizing the continuous-stable to target Provide the foundation.Additionally, the present invention uses array acceptor antenna to receive direct-path signal and target echo signal simultaneously, then lead to Cross Wave beam forming and respectively obtain direct-path signal component and target echo signal component, it is not necessary to two single antennas connect respectively Receive direct-path signal and target echo signal, be non-coherent between different receivers array carrying out during target detection, no Process with need not to carry out Phase synchronization between array acceptor.

Accompanying drawing explanation

Fig. 1 is the topological structure schematic diagram of the distributed passive radar of the present invention.

Fig. 2 is distributed passive radar i-th j of the present invention geometrical relationship figure to transmitter-target-receiver.

Fig. 3 is that i-th j of the present invention is individual bistatic to corresponding direct wave and the Wave beam forming schematic diagram of target echo signal.

Fig. 4 is the distributed passive radar object detection method implementing procedure figure of the present invention.

Fig. 5 is the computer artificial result schematic diagram of the embodiment of the present invention.

Detailed description of the invention

Below in conjunction with Figure of description, the present invention is described in further detail.

As it is shown in figure 1, distributed Passive Radar System includes N_tIndividual transmitter, transmitter is also referred to as in passive radar field For non-cooperation radiation source, N_rIndividual array acceptor, 1 target, wherein N_t>=2, N_r≥2。

As in figure 2 it is shown, the i-th j in distributed Passive Radar System is also referred to as the i-th j to transmitter-target-receiver Bistatic right, the position of i-th transmitter and speed are designated as d respectivelyⁱWithI=1 ..., N_t, the position of jth array acceptor Put and be designated as r with speed respectively^jWithJ=1 ..., N_r, and the position of target and speed be designated as respectively t andWherein dⁱ、r^j、t、It it is all the function of time.Generally, transmitter and receiver, target are all motions.I-th transmitter is to The distance of j receiver isSimilarly,WithRepresent i-th respectively Individual transmitter range-to-go and target are to the distance of jth receiver.Jth reception antenna is to haveThe battle array of individual array element Row,1≤j≤N_r, the position of the n-th array element isWhereinIt it is reference array element Position,It is n-th array element sensing offset vector relative to reference array element, andThe array number of receiving antenna array is all Identical, i.e.J=1 ..., N_r.N-th array element of jth receiver to the unit pointing vector of position x is I.e.In far field, for given x,I.e. a certain from array elements to far field The unit pointing vector approximately equal of position.

As it is shown on figure 3, under MIMO geometry framework in distributed Passive Radar System, all passive receivers all use Array antenna, forms reference channel and targeted surveillance passage respectively by the method for Wave beam forming, thus realizes direct-path signal Reception respectively with target echo signal.

The signal of i-th radiation emission is

${\tilde{u}}^i\left(t\right)=u^i\left(t\right)e^{{\mathrm{j\ω}}_c^{i}t},t\∈\[0,T\]---\left(1\right)$

Wherein,For carrier frequency, T is signal duration,For the signal that i-th transmitter is corresponding, uⁱT () is corresponding Complex envelope, frequency domain is Uⁱ(ω), a width of B is carriedⁱ, and work as | ω | ＞ π BⁱTime, Uⁱ(ω) ≈ 0,At frequency Territory does not has overlap.

Signal travels to jth receiver, the n-th of jth array acceptor along direct path and destination path passage The signal that individual array element receivesIt is to make an uproar from all direct-path signals in receiver band and target echo and receiver Sound sum, i.e.

${\tilde{s}}_n^j\left(t\right)=\underset{i=1}{\overset{N_t}{\Σ}}{a}_{d,n}^{ij}\left(t\right){\tilde{u}}^i(t-{\mathrm{\τ}}_{d,n}^{ij}(t\left)\right)+\underset{i=1}{\overset{N_t}{\Σ}}{\mathrm{\α}}^{ij}{a}_{t,n}^{ij}\left(t\right){\tilde{u}}^i(t-{\mathrm{\τ}}_{t,n}^{ij}(t\left)\right)+{\tilde{n}}_n^{ij}\left(t\right)---\left(2\right)$

Wherein,WithIt is respectively direct path and the range coefficient of destination path passage, α^ijFor individual with the i-th j Bistatic corresponding target is answered bistatic reflection coefficient,WithThe most corresponding direct path and destination path lead to The propagation delay in road,It is that power spectral density isExtended stationary white Gaussian noise, Carry a width of B^j, carrier frequency isChannel factorWithConsider transmitting, propagation and direct path and destination path The impact of passage, is respectivelyWherein, The Effective Radiated Power of x is pointed to for i-th transmitter,Launch the wavelength of signal for i-th transmitter, c is the light velocity,In [0, T],WithAll without having significant change, therefore,WithSignalAfter downconverted and frequency domain channelization processes, extract the complex baseband signal of each transmitting signal, The complex baseband signal of note i-th passage isUtilize formula (1) and (2), the signal that the n-th array element of jth receiver receives For

$s_n^{ij}\left(t\right)=a_d^{ij}{e}^{j({\mathrm{\θ}}^j-{\mathrm{\ω}}_c^i{\mathrm{\τ}}_{d,n}^{ij}(t))}{u}^i(t-{\mathrm{\τ}}_{d,n}^{ij}(t\left)\right)+{\mathrm{\α}}^{ij}{a}_t^{ij}{e}^{j({\mathrm{\θ}}^j-{\mathrm{\ω}}_c^i{\mathrm{\τ}}_{t,n}^{ij}(t))}{u}^i(t-{\mathrm{\τ}}_{t,n}^{ij}(t\left)\right)+{\tilde{n}}_n^{ij}\left(t\right)---\left(3\right)$

Wherein, θ^jFor the unknown phase of local oscillator during jth receiver down-converted, show it is non-phase between different receivers Ginseng, need not carry out Phase synchronization between different receivers array and process.

As shown in Figure 4, the present invention provides a kind of method realizing distributed passive radar target detection and localization, is embodied as Mode comprises the following steps:

A1. build under MIMO geometry framework, the transmitting signal quilt of i-th radiation source in distributed Passive Radar System N-th array element of jth array acceptor receives and direct-path signal component after Base-Band ProcessingDetailed process is as follows:

$s_{d,n}^{ij}\left(t\right)=a_d^{ij}{e}^{j({\mathrm{\θ}}^j-{\mathrm{\ω}}_c^i{\mathrm{\τ}}_{d,n}^{ij}(t))}{u}^i(t-{\mathrm{\τ}}_{d,n}^{ij}(t\left)\right)---\left(4\right)$

Wherein, For between i-th transmitter to the n-th array element of jth array acceptor Distance, it is considered to after array element distance, is further represented as

$s_{d,n}^{ij}\left(t\right)=a_d^{ij}{e}^{j({\mathrm{\θ}}^j-{\mathrm{\ω}}_c^i{\mathrm{\Δ\τ}}_n^{ij}(d^i))}{u}^i(t-{\mathrm{\τ}}_d^{ij}(t)-{\mathrm{\Δ\τ}}_n^{ij}(d^i\left)\right)e^{-{\mathrm{j\ω}}_c^i{\mathrm{\τ}}_d^{ij}\left(t\right)}---\left(5\right)$

Complex exponential itemThe most relevant with array number n.OrderFor the phase place of complex exponential item,

${\mathrm{\θ}}_n^{ij}\left(d^i\right)\stackrel{\mathrm{\Δ}}{=}-{\mathrm{\ω}}_c^i{\mathrm{\Δ\τ}}_n^{ij}\left(d^i\right)=-\left(\frac{{\mathrm{\ω}}_c^i}{c}\right){\mathrm{\ΔR}}_n^{ij}\left(d^i\right)\≈\left(\frac{2\mathrm{\π}}{{\mathrm{\λ}}^i}\right){\hat{k}}^j\left(d^i\right)\·{\mathrm{\δ}}_n^j---\left(6\right)$

Wherein,Formula (5) is carried out arrowband approximation, i.e. complex envelope at whole array The most all it is approximately constant, then

$s_{d,n}^{ij}\left(t\right)\≈a_d^{ij}{e}^{j({\mathrm{\θ}}^j+{\mathrm{\θ}}_n^{ij}(d^i))}{u}^i(t-{\mathrm{\τ}}_d^{ij}(t\left)\right)e^{-{\mathrm{j\ω}}_c^i{\mathrm{\τ}}_d^{ij}\left(t\right)}---\left(7\right)$

Then utilizeSubstitute into (7)

$s_{d,n}^{ij}\left(t\right)=a_d^{ij}{e}^{j({\mathrm{\θ}}^j+{\mathrm{\θ}}_n^{ij}(d^i))}{u}^i(\mathrm{\α}t-{\mathrm{\τ}}_d^{ij})e^{-{\mathrm{j\ω}}_c^i{\mathrm{\τ}}_d^{ij}}{e}^{{\mathrm{j\ω}}_d^{ij}t}---\left(8\right)$

Wherein,For time scale factor,For non-cooperation radiation source and array acceptor Between the Doppler frequency that causes of relative motion, be defined as

${\mathrm{\ω}}_d^{ij}\stackrel{\mathrm{\Δ}}{=}-\left(\frac{{\mathrm{\ω}}_c^i}{c}\right){\stackrel{\·}{R}}_0^{ij}=-\left(\frac{2\mathrm{\π}}{{\mathrm{\λ}}^i}\right)\frac{(r^j-d^i)\·({\stackrel{\·}{r}}^j-{\stackrel{\·}{d}}^i)}{\mathrm{||}{r}^j-d^i\mathrm{||}}{|}_{t=0}---\left(9\right)$

What then the n-th array element of jth receiver received is believed by the direct wave after Base-Band Processing of i-th radiation emission Number component is

In formula, (a) is amplitude scale factor, and (b) is unknown local oscillator phase place, and (c) is that the n-th array element receives direct-path signal The phase contrast of reference array element relatively, (d) is the phase contrast introduced with reference to carrier frequency time delay, the complex baseband signal that (e) delays when being, F () is the Doppler modulation factor.

Therefore, direct-path signal component is configured to

$s_{d,n}^{ij}\left(t\right)={\mathrm{\γ}}_d^{ij}{e}^{{\mathrm{j\θ}}_n^{ij}\left(d^i\right)}{u}^i(t-{\mathrm{\τ}}_d^{ij})e^{{\mathrm{j\ω}}_d^{ij}t}---\left(11\right)$

Wherein,It is i-th j direct path passage propagation coefficient,

A2. structure target travel and target are respectively when scattering is different, and the signal of i-th radiation emission is after target reflection Received by the n-th array element of jth array acceptor and target echo signal component after Base-Band ProcessingConcrete mistake Journey is as follows:

$s_{t,n}^{ij}\left(t\right)={\mathrm{\α}}^{ij}{a}_t^{ij}{e}^{j({\mathrm{\θ}}^j-{\mathrm{\ω}}_c^i{\mathrm{\τ}}_{t,n}^{ij}(t))}{u}^i(t-{\mathrm{\τ}}_{t,n}^{ij}(t\left)\right)---\left(12\right)$

It is further represented as

In formula, (a) is amplitude scale factor, and (b) is unknown local oscillator phase place, and (c) is that the n-th array element receives target echo letter The phase contrast of number relative reference array element, (d), with reference to the carrier phase factor, delays complex baseband signal, (f) Doppler frequency time (e) The factor, andFor bistatic time delay to jth receiver from i-th transmitter to target, i.e.

${\mathrm{\τ}}_t^{ij}\stackrel{\mathrm{\Δ}}{=}\left(\frac{1}{c}\right)(R_1^i+R_2^j)=\left(\frac{1}{c}\right)\left(\right||t-d^i||+||r^j-t|\left|\right){|}_{t=0}---\left(14\right)$

It is that the n-th array element receives the target echo signal phase contrast relative to reference array element, i.e.

${\mathrm{\θ}}_n^{ij}\left(t\right)\stackrel{\mathrm{\Δ}}{=}-{\mathrm{\ω}}_c^i{\mathrm{\Δ\τ}}_n^{ij}\left(t\right)=k^{ij}\left(t\right)\·{\mathrm{\δ}}_n^j---\left(15\right)$

Bistatic Doppler frequency shift for target

${\mathrm{\ω}}_t^{ij}\stackrel{\mathrm{\Δ}}{=}-\left(\frac{{\mathrm{\ω}}_c^i}{c}\right)({\stackrel{\·}{R}}_1^{ij}+{\stackrel{\·}{R}}_2^{ij})=-\left(\frac{2\mathrm{\π}}{{\mathrm{\λ}}^i}\right)\[\frac{(t-d^i)\·(\stackrel{\·}{t}-{\stackrel{\·}{d}}^i)}{\left|\right|t-d^i\left|\right|}+\frac{(r^j-t)\·({\stackrel{\·}{r}}^j-\stackrel{\·}{t})}{\left|\right|r^j-t\left|\right|}\]{|}_{t=0}---\left(16\right)$

Therefore, the signal of i-th radiation emission is received by the n-th array element of jth array acceptor after target reflection Arrive, and the target echo signal component after Base-Band Processing is configured to

$s_{t,n}^{ij}\left(t\right)={\mathrm{\γ}}_t^{ij}{e}^{{\mathrm{j\θ}}_n^{ij}\left(t\right)}{u}^i(t-{\mathrm{\τ}}_t^{ij})e^{{\mathrm{j\ω}}_t^{ij}t}---\left(17\right)$

Wherein,It is i-th j destination path channel factor,

A3. to the i-th j bistatic centering, what the n-th array element of jth receiver received is returned by direct wave and target Signal that is that involve receiver noise and that formCarry out quantifying sampling, use its discrete shape of delay-Doppler operator representation Formula, and provide the target echo signal after Wave beam formingWith direct wave reference signalDetailed process is as follows:

WithSample frequency carry out quantify sampling, thenObtaining discrete signal form is

$s_n^{ij}\[l\]=s_{d,n}^{ij}\[l\]+s_{t,n}^{ij}\[l\]+n_n^{ij}\[l\],l=0,...,L^i-1---\left(18\right)$

Wherein,For total sampling number, direct waveAnd target echoQuantized versions be respectively

Wherein,Being respectively the normalization Doppler frequency of each sample, unit is radian,It is respectively the normalization time delay of each sample.Note Noise samples sequenceσ²=N₀BⁱFor average noise power,δ_nFor Kronecker symbol.For transmitted waveform, the l element is

Definition

D_L(x)=diag ([e^j(0)x,e^j(1)x,…,e^j(L-1)x]) (21)

Wherein, diagonal entry in diag (x)It is the square formation of L × L, therefore [diag (x)]_n,n=[x]_n.? After, orderFor Discrete Fourier transform at the tenth of the twelve Earthly Branches, (m, n) individual element is for it

${\[W\]}_{m,n}=\frac{1}{\sqrt{L}}{e}^{-j\left(\frac{2\mathrm{\π}}{L}\right)mn}---\left(22\right)$

Wherein, m=0 ..., L-1, n=0 ..., L-1., then

Definition delay-Doppler operatorFor

Due toTherefore time delay is many General Le operatorFor unitary operator, i.e.WhereinIt is Lⁱ×Lⁱ's Unit matrix.

Therefore, the discrete form of the component of direct wave and target echo signal is respectively

Because direct-path signal is to be received, so jth connects by identical array acceptor with target echo signal Receipts machine array the n-th array element receives the discrete form of signal

Wherein, It is a length of LⁱZero vector.

Therefore, the target echo signal obtained by Wave beam forming respectivelyWith direct wave reference signalFor

$s_s^{ij}=\underset{n=1}{\overset{N_e}{\Σ}}{\[b_s^{ij}\]}_n^{*}{s}_n^{ij}---\left(28\right)$

$s_r^{ij}=\underset{n=1}{\overset{N_e}{\Σ}}{\[b_r^{ij}\]}_n^{*}{s}_n^{ij}---\left(29\right)$

It is respectively targeted surveillance passage and the Beam-former of direct wave reference channel.

A4. N in distributed Passive Radar System is utilized_rThat individual array acceptor receives and N_tIndividual non-cooperation radar emission All direct waves and target echo signal that source is corresponding are sampled, the matrix s that structure is made up of direct wave and target echo signal, tool Body process is as follows:

OrderFor the space pointing vector in x directionNoteThe then all N of jth array acceptor_eIt is corresponding with i-th radiation source that individual array element receives Signal phasorFor

$s^{ij}=(M_d^{ij}+M_t^{ij})u^i+n^{ij},i=1,...,N_t,j=1,...,N_r---\left(30\right)$

Wherein,Variance is σ², matrixWith It is respectively Representing that Kronecker amasss, time delay is many General Le operatorWithIt is respectively

Therefore, all N_rThe sampling s corresponding with i-th radiation source that individual array acceptor receivesⁱFor:

And with all N_tIndividual non-cooperation radiation source and N_rThe matrix of all sampling compositions that individual array acceptor is corresponding is

I.e. s is all N_tIndividual non-cooperation radiation source correspondence sⁱThe matrix of composition.

B1. introduce position and the velocity information of target to be detected, as object detection unit, utilize echo-signal matrix s Building the inspection of binary alternative hypothesis, detailed process is as follows:

Make the position of target to be detected corresponding with speedUnit, i.e. detector unit, wherein p,Represent mesh respectively Target position and speed.Build the inspection of binary alternative hypothesis, i.e.

Wherein, i=1 ..., N_t, j=1 ..., N_r,Table Show the space pointing vector in p directionAndCorrespondence mesh when being P for target location The coefficient of mark outlet openings,For dbjective state it isCorresponding delay-Doppler operator.

B2. the hypothesis testing built is utilized, its Generalized Logarithmic likelihood ratio of deriving, obtain the inspection of distributed passive radar target Centralized detection statistic ξ surveyed_rs, detailed process is as follows；

Owing to receiver noise is unrelated with transmitter channels, soConditional probability density p under assuming₁(s|γ_d,γ_p, U) be

$p_1\left(s\right|{\mathrm{\γ}}_d,{\mathrm{\γ}}_p,u)=\underset{i=1}{\overset{N_t}{\Π}}{p}_1^i\left(s^i\right|{\mathrm{\γ}}_d^i,{\mathrm{\γ}}_p^i,u^i)---\left(34\right)$

Wherein,AndIn like manner be given ?Conditional probability density p under assuming₀(s|γ_d,u).Launch signal u and channel factor γ_dAnd γ_pAll determining that property is not Know parameter.Therefore,It is to launch signal u and channel factor γ_d、γ_pFor the composite hypothesis of parameter,It is to launch signal u With channel factor γ_dFor the composite hypothesis of parameter, and the unknown quantity in likelihood ratio test uses its maximal possibility estimation to replace.

Make l₁(γ_d,γ_p, u | s)=logp₁(s|γ_d,γ_p, u), l₀(γ_d, u | s)=logp₀(s|γ_d, u), then broad sense Log-likelihood function is to be written as

It is derived by l respectively₁(γ_d,γ_p, u | s) and l₀(γ_d, u | after analytical expression s), obtain the inspection of centralized target Survey statistic ξ_rsFor

Wherein, λ₁() is the eigenvalue of maximum of matrix parameter；For Gram matrix, ()^H Represent hermitian transposition, It it is the mesh after delay-Doppler compensates Mark echo-signalI.e. remove time delay and the supervision channel targets echo-signal of Doppler frequency shift, It it is the reference signal after delay-Doppler compensatesWhen i.e. removing Prolong the direct wave channel signal with Doppler frequency shift；κ_rsFor detection threshold, by distributed passive The false-alarm probability of radar system determines.

B3. according to the sampling of all signals in actual distribution formula Passive Radar System, target detection statistic ξ is calculated_rs, By comparing detection statistic ξ_rsWith thresholding κ_rsSize, then determine that whether target exists, complete target detection, concrete mistake Journey is as follows:

Utilize N in distributed Passive Radar System_rIndividual array acceptor correspondence N_tIndividual non-all of cooperation Radar emitter are adopted Sample structure echo-signal matrix, target detection statistic ξ_rs, work as ξ_rs≥κ_rsTime, then judge that target exists, and target location and speed Degree state isAnd work as ξ_rs＜ κ_rsTime, then judge that target does not exists.

As it is shown in figure 5, the computer artificial result schematic diagram of the embodiment of the present invention.In figure, BRng contour represents bistatic Distance contour, target occurs near locations of real targets, and therefore this method also achieves while realizing target detection Location to target.In this simulated environment background, the position of two transmitters is respectively d¹=[0.5,4] km and d²=[- 0.5 ,-4] km, the position of three receivers is respectively r¹=[-4,2], r²=[-4,0.5] and r³=[-4 ,-2.5] km, target At t=[4,0] km, target speed isTransmitter signal carrier frequency is respectively 8.0GHz And 8.1GHz, isotropically radiated power isUniform linear array is made up of 6 array elements, and all receiver antennas are all It is the array element uniform linear array that is spaced apart 1.875cm, sensing+p_xDirection, the lobe pattern of each array element isReceiver Between there is no Phase synchronization.Complex baseband signalSample rate f_s=500kHz, the correlative accumulation time is T=2ms, putting down of target echo All signal to noise ratios are SNR_avg=-15dB, the average signal-to-noise ratio of direct wave is DNR_avg=15dB,uⁱ= exp{jθⁱ,It is separate random phase vectors, between [0,2 π], obeys being uniformly distributed, L=f_sT=1000, Target scatter section area is 10dBsm.

Claims (3)

1. the method realizing distributed passive radar target detection, it is characterised in that comprise the following steps:

(1), under MIMO geometry framework, distributed passive radar direct-path signal component and target echo signal component are set up Enforcement step, specifically include following sub-step:

A1. building under MIMO geometry framework, in distributed Passive Radar System, the signal of i-th radiation emission is by jth N-th array element of individual array acceptor receives and direct-path signal component after Base-Band Processing

When A2. building target travel, the signal of i-th radiation emission quilt after target reflection in distributed Passive Radar System N-th array element of jth array acceptor receives and target echo signal component after Base-Band Processing

A3. to the i-th j bistatic centering, what the n-th array element of jth array acceptor received is returned by direct wave and target Signal that is that involve receiver noise and that formCarry out quantifying sampling, introduce its discrete shape of delay-Doppler operator representation Formula, and provide the target echo signal after Wave beam formingWith direct wave reference signal

A4. N in distributed Passive Radar System is utilized_rThat individual array acceptor receives and N_tIndividual non-cooperation Radar emitter pair The all direct waves answered and target echo signal sampling, the matrix s that structure is made up of direct wave and target echo signal；

(2), under MIMO geometry framework, the enforcement step of centralized target detection carried out by distributed passive radar, specifically includes Following sub-step:

B1. introduce position and the velocity information of target to be detected, as object detection unit, utilize echo-signal matrix s to build Binary alternative hypothesis is checked；

B2. the hypothesis testing built is utilized, its Generalized Logarithmic likelihood ratio of deriving, obtain distributed passive radar target detection Centralized detection statistic ξ_rs；

B3. according to the actual samples of signals all in distributed Passive Radar System, target detection statistic ξ is calculated_rs, pass through Relatively detection statistic ξ_rsWith thresholding κ_rsSize, then determine that whether target exists, complete target detection.

A kind of method realizing distributed passive radar target detection, it is characterised in that described step Suddenly each array acceptor of (1) receives direct-path signal and target echo signal simultaneously, then is divided by beamforming algorithm Do not obtain direct-path signal component and target echo signal component.

A kind of method realizing distributed passive radar target detection, it is characterised in that described step Suddenly (1) is non-coherent between different receivers array, and need not between different receivers array during target detection Carry out Phase synchronization to process.