CN103713289A - Object detection method based on distribution type Phased-MIMO combined processing - Google Patents

Abstract

The invention discloses an object detection method based on distribution type Phased-MIMO combined processing. Multiple sub-arrays are arranged on different positions in a distribution way, and emission coherent signals are formed in the internal parts of the sub-arrays via emission wave beams so that coherent gain is acquired. The signals between the sub-arrays radiate to different positions of objects in a mutually orthogonal way so that object diversity is acquired. A receiving array detects the objects through forming receiving wave beams and matching filtering waves. Coherent and non-coherent gain can be acquired by the method. Besides, the method has characteristics that interference is eliminated, reverberation is inhibited and scintillation of the objects is resisted. For the distribution type objects, when wave beam width of the sub-arrays is greater than an object size, detection performance is better than that of a conventional phased array.

Description

Object detection method based on distributed Phased-MIMO Combined Treatment

Technical field

The present invention relates to a kind of based on distributed Phased-MIMO Combined Treatment for target detection technology under water, belong to Underwater Acoustic Object Detection Techniques field.

Background technology

When carrying out Shallow Water Target detection, the main interference that affects active probe is reverberation.Reverberation and target echo all cause by transmitting, and its spectral property correlativity in the situation that Doppler shift is little is very large.The characteristic of reverberation is also relevant with propagation channel, and due to the impact of Shallow Water Acoustic Channels, reverberation also has Space-Time variation characteristic, and presents strong non-stationary.Therefore, anti-reverberation is a Research Challenges of detecting underwater object.On the other hand, the spatial non-uniformity of target has also caused the flicker instability of active sonar detection performance, and the emission array in single base is difficult to guarantee the stability of the detection of a target for the interference of distributed target and signal.

In 10 years of past, multiple-input and multiple-output (Multiple Input Multiple Output is called for short " MIMO ") technology is rapid in the research and development of field of radar.Traditional phased array drives to signal the diversity gain that transmitting can be obtained emission array, realizes effective focusing of target is irradiated, thereby reach anti-reverberation, reduces the object of disturbing effect.Meanwhile, distributed mimo system, because it can obtain transmitted waveform diversity and target diversity, is also widely used in target detection and location.Yet due to time delay and the two expansions of Doppler of underwater acoustic channel, MIMO technology is slower in the development in sonar field.2006, I.Bekkerman and J.Tabrikian have proposed first radar and the unified MIMO of sonar processes framework.Consider two expansions of underwater acoustic channel, in conjunction with phased array and MIMO technology, propose a kind of distributed Phased-MIMO Combined Treatment technology based on broadband signal model here.

Summary of the invention

The object of the invention is the problem existing for existing single base active sonar Detection Techniques, consider the spatial character of reverberation interference and distributed object, a kind of object detection method based on distributed Phased-MIMO Combined Treatment is provided.

For achieving the above object, the technical solution used in the present invention is: the object detection method that the present invention is based on distributed Phased-MIMO Combined Treatment comprises the steps:

1) at transmitting terminal, arrange M transmitting submatrix, each is launched submatrix and comprises M _kindividual transmitting transducer array element; Each transmitting transducer array element in each transmitting submatrix is connected with the output terminal of power amplifier, and the input end of described power amplifier is connected with the output terminal of corresponding signal generating apparatus; Each is launched transmitting transducer array element in submatrix and is arranged to the minimum value of the half-wavelength transmitting that spacing between even linear array and adjacent transmission transducer array element is less than or equal to the transmitting submatrix at place; Each spacing of launching between submatrix meets the requirement shown in formula (1):

$d_t>\frac{R_t{\mathrm{\λ}}_{\max }}{D}---\left(1\right)$

At receiving end, arrange that N receives submatrix, each receives submatrix and comprises N _lindividual nautical receiving set array element; Each receives nautical receiving set array element in submatrix and is connected with signal collecting device accordingly, and each receives nautical receiving set array element in submatrix and is arranged to the minimum value that spacing between even linear array and adjacent nautical receiving set array element is less than or equal to the half-wavelength transmitting accordingly; Each spacing receiving between submatrix meets the requirement shown in formula (2):

$d_r>\frac{R_r{\mathrm{\λ}}_{\max }}{D}---\left(2\right)$

Wherein, M is more than or equal to 1 positive integer, M _kfor be more than or equal to 1 positive integer and

r _trepresent that the corresponding transmitting submatrix of transmitting terminal is to the distance of target's center, D represents the size of target, d _trepresent the spacing between adjacent transmitting submatrix, d _rrepresent the spacing between adjacent reception submatrix, λ _maxthe maximal value that represents all wavelength that transmit; N represents to be more than or equal to 1 positive integer, N _lrepresent to be more than or equal to 1 positive integer and

r _rrepresent that the corresponding reception submatrix of receiving end is to the distance of target's center;

2) described in each, signal generating apparatus generation transmits

Wherein, E represents the gross energy transmitting,

M represents to launch the number of submatrix,

$a_t^k({\mathrm{\&theta;}}_k,f_m)={[1,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_k}{c}\sin {\mathrm{\&theta;}}_k},\&CenterDot;\&CenterDot;\&CenterDot;,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_k}{c}\sin {\mathrm{\&theta;}}_k(M_k-1)}]}^T,$ Wherein, [... ] ^ttransposition symbol, θ _kthe angle of arrival that target's center arrives transmitting submatrix k, k=1,2 ..., M, f _mm frequency of the signal of transmitting submatrix k transmitting, m=1,2 ... L, L is the frequency number of the signal of each transmitting submatrix transmitting, c is the velocity of propagation transmitting, d _kthe spacing between the adjacent transmission transducer array element in transmitting submatrix k, M _kbe the transmitting transducer array element number that transmitting submatrix k comprises, i represents imaginary number;

{ S _k(f _m) represent transmitting of transmitting submatrix k, ‖ S _k(f _m) ‖ ²=1/L,

Described in each, signal generating apparatus transmits after amplifying by power amplifier, sending each transmitting transducer array element in corresponding transmitting submatrix to converts acoustic signals to and is transmitted into wish and surveys waters;

3) respectively receive submatrix by the S that transmits of the corresponding transmitting submatrix receiving _k(f _m) echo R _lk(f _m) sending corresponding signal collecting device to, described signal collecting device is to received echo R _lk(f _m) carry out received beam as the formula (3) and form:

$Y_{\mathrm{lk}}\left(f_m\right)=(b_r^l({\mathrm{\&theta;}}_l,f_m){)}^H{R}_{\mathrm{lk}}\left(f_m\right)---\left(3\right)$

In formula (3), (...) ^hconjugate transpose symbol,

$b_r^l({\mathrm{\&theta;}}_l,f_m)={[1,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_l}{c}\sin {\mathrm{\&theta;}}_l},\&CenterDot;\&CenterDot;\&CenterDot;,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_l}{c_l}\sin {\mathrm{\&theta;}}_l(N_l-1)}]}^T,$ Wherein, θ _lthat target's center arrives the angle of arrival that receives submatrix l, l=1,2,, N, d _lthe spacing between the adjacent nautical receiving set array element receiving in submatrix l, N _lbe to receive the nautical receiving set array element number that submatrix l comprises, i represents imaginary number;

By Y _lk(f _m) by the method shown in formula (4), mate:

$T=\underset{l=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{L}{\mathrm{\&Sigma;}}}{\left|\right|S_k^{*}\left(f_m\right)Y_{\mathrm{lk}}\left(f_m\right)\left|\right|}^2---\left(4\right)$

In formula (4), ∑ represents the symbol of suing for peace, || ... || ²expression is to vector delivery, S _k(f _m) representing transmitting of transmitting submatrix k, N is the number that receives submatrix, and M is the number of transmitting submatrix, and L is the frequency number of the signal of each transmitting submatrix transmitting;

By target's center to all distance R that respectively receive submatrix _lcorresponding T value is depicted as R _l-T two dimensional image; Then observe R _l-T two dimensional image, if there is peak value in target's center to receiving between submatrix, shows to exist target.

Compared with prior art, the invention has the beneficial effects as follows: traditional phase control type array and MIMO Signal with Distributed Transmit Antennas are combined, thereby when obtaining certain resolving power inhibition reverberation interference, thereby obtain target diversity information, reach anti-target glint characteristic, stablize active sonar detection performance.Numerical simulation and experimental verification, be distributed object in target, and in the situation of high s/n ratio, Phased-MIMO active target Detection Techniques are due to traditional phased array Detection Techniques.

Accompanying drawing explanation

Fig. 1 is that emission array and receiving array are with respect to the schematic diagram of structuring the formation of target;

Fig. 2 (a) is that the velocity of sound is with the curve map of change in depth; Fig. 2 (b) is the environment schematic diagram of one embodiment of the present of invention;

Fig. 3 (a) is the detection Output rusults of the Phased-MIMO active sonar system that transmitting PCW signal is corresponding; Fig. 3 (b) is the detection Output rusults of the Phased-Array active sonar system that transmitting PCW signal is corresponding;

Fig. 4 (a) is the detection Output rusults of the Phased-MIMO active sonar system that transmitting LFM signal is corresponding; Fig. 4 (b) is the detection Output rusults of the Phased-Array active sonar system that transmitting LFM signal is corresponding.

Embodiment

The inventive method comprises the steps:

1) at transmitting terminal, arrange M transmitting submatrix, be numbered 1 .., M, M is more than or equal to 1 positive integer.K(k=1,2 ..., M) individual transmitting submatrix comprises M _kindividual transmitting transducer array element, is numbered 1,2 ..., M _k, M _kfor be more than or equal to 1 positive integer and

r _trepresent that transmitting terminal is to the distance of target's center, D represents the size of target.By one, there is M * M _kthe output of the signal generating apparatus on road connects one and has M * M _kthe input end of the power amplifier on road, the output terminal of power amplifier is connected to M * M _kin individual transmitting transducer array element.At the inside of k transmitting submatrix, the spacing d between adjacent transmission transducer array element _kthe minimum value that is less than or equal to the half-wavelength transmitting of k transmitting submatrix, the spacing between adjacent transmission submatrix is d _tmeet the requirement shown in formula (1):

$d_t>\frac{R_t{\mathrm{\&lambda;}}_{\max }}{D}---\left(1\right)$

At receiving end, arrange that N receives submatrix, be numbered 1 .., N, N represents to be more than or equal to 1 positive integer.L(l=1,2 ..., N) individual reception submatrix comprises N _lindividual nautical receiving set array element, N _lrepresent to be more than or equal to 1 positive integer and

r _rrepresent that receiving end is to the distance of target's center.L spacing d that receives the adjacent nautical receiving set array element of submatrix inside _lbe less than or equal to l minimum value that receives the half-wavelength of the signal that submatrix receives, the spacing between adjacent reception submatrix is d _rmeet the requirement shown in formula (2):

$d_r>\frac{R_r{\mathrm{\&lambda;}}_{\max }}{D}---\left(2\right)$

K(k=1,2 ..., the M) q(q=1 in individual transmitting submatrix, 2 ..., M _k) m frequency signal of individual transmitting transducer array element transmitting be

wherein, [... ] ^ttransposition symbol, θ _kthe angle of arrival that target's center arrives transmitting submatrix k, k=1,2 ..., M, f _mm frequency of the signal of transmitting submatrix k transmitting, m=1,2 ... L, L is the frequency number of the signal of each transmitting submatrix transmitting, c is the velocity of propagation transmitting, d _kthe spacing between the adjacent transmission transducer array element in transmitting submatrix k, ‖ S _k(f _m) ‖ ²=1/L, m=1,2 ... L, ‖ S _i(f) S _j(f) ‖=0, i ≠ j.Being write as vector form is

wherein

be that k transmitting submatrix is at frequency f _mpoint to the driving vector of target's center.

The signal frequency of k the transmitting submatrix transmitting that corresponding l p the nautical receiving set array element receiving in submatrix is received is f _mecho can be expressed as:

$r_{\mathrm{lk},p}\left(f_m\right)={\mathrm{\&alpha;}}_k^m{\mathrm{\&epsiv;}}_k^m{\mathrm{\&zeta;}}_l^m{M}_k\sqrt{E/M}{s}_k\left(f_m\right)e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_l}{c}\sin {\mathrm{\&theta;}}_l(p-1)}+n_{\mathrm{lk},p}^m---\left(5\right)$

Wherein, m the frequency that is the transmitting of k transmitting submatrix is irradiated to the scattering coefficient of equal value after scatterer;

represent that transmitting submatrix is to the transmission loss (TL) of target,

represent that respectively transmitting submatrix is to target, target is to the transmission loss (TL) that receives submatrix; Being write as vector form is:

$r_{\mathrm{lk}}\left(f_m\right)={\mathrm{\&alpha;}}_k^m{\mathrm{\&epsiv;}}_k^m{\mathrm{\&zeta;}}_l^m{M}_k\sqrt{E/M}{s}_k\left(f_m\right)a_r^l({\mathrm{\&theta;}}_l,f_m)+n_{\mathrm{lk}}^m---\left(6\right)$

for target's center receives submatrix at frequency f to l _mresponse vector;

the multiple noise of Gauss for zero-mean.

3) for each, receive submatrix by the S that transmits of the corresponding transmitting submatrix receiving _k(f _m) echo R _lk(f _m) sending corresponding signal collecting device to, described signal collecting device is to received echo R _lk(f _m) carry out received beam as the formula (3) and form:

$Y_{\mathrm{lk}}\left(f_m\right)={\left(b_r^l({\mathrm{\&theta;}}_l,f_m)\right)}^H{R}_{\mathrm{lk}}\left(f_m\right)---\left(3\right)$

In formula (3), (...) ^hconjugate transpose symbol,

$b_r^l({\mathrm{\&theta;}}_l,f_m)={[1,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_l}{c}\sin {\mathrm{\&theta;}}_l},\&CenterDot;\&CenterDot;\&CenterDot;,e^{-\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">i</figure-callout>}2\mathrm{\&pi;}{f}_m\frac{d_l}{c_l}\sin {\mathrm{\&theta;}}_l(N_l-1)}]}^T,$ Wherein, θ _lthat target's center arrives the angle of arrival that receives submatrix l, l=1,2,, N, d _lthe spacing between the adjacent nautical receiving set array element receiving in submatrix l, N _lbe to receive the nautical receiving set array element number that submatrix l comprises, i represents imaginary number;

4) deal with data that step 3) obtains can be expressed as:

$\begin{array}{c}{Y}_{\mathrm{lk}}\left(f_m\right)={\left(a_r^l({\mathrm{\&theta;}}_l,f_m)\right)}^H({\mathrm{\&alpha;}}_k^m{\mathrm{\&epsiv;}}_k^m{\mathrm{\&zeta;}}_l^m{M}_k\sqrt{E/M}{s}_k\left(f_m\right)a_r^l({\mathrm{\&theta;}}_l,f_m)+n_{\mathrm{lk}}^m)\\ ={\mathrm{\&alpha;}}_k^m{\mathrm{\&epsiv;}}_k^m{\mathrm{\&zeta;}}_l^m{M}_k{N}_l\sqrt{E/M}{s}_k\left(f_m\right)+v_{\mathrm{lk}}^m\end{array}---\left(7\right)$

Definition

represent that m transmitting submatrix is to j attenuation coefficient of equal value that receives submatrix, formula (7) can be written as again:

$Y_{\mathrm{lk}}\left(f_m\right)=M_k{N}_l\sqrt{E/M}{\mathrm{\&lambda;}}_{\mathrm{lk}}^m{s}_k\left(f_m\right)+v_{\mathrm{lk}}^m---\left(8\right)$

Be the matrix form of formula (8) as the formula (9):

$Y=\sqrt{E/M}\mathrm{Q\&lambda;}+v---\left(9\right)$

Wherein, MNL * MNL dimension diagonal matrix Q is as the formula (10):

$\begin{array}{c}Q=\mathrm{diag}[M_1{N}_1{s}_1\left(f_1\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_1{N}_1{s}_1\left(f_L\right),\\ M_2{N}_1{s}_2\left(f_{L+1}\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_2{N}_1{s}_2\left(f_{L+L}\right),\&CenterDot;\&CenterDot;\&CenterDot;,\\ M_M{N}_1{s}_M\left(f_{(M-1)L+1}\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_M{N}_1{s}_2\left(f_{\mathrm{ML}}\right),\\ M_1{N}_2{s}_1\left(f_1\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_1{N}_2{s}_1\left(f_L\right),\&CenterDot;\&CenterDot;\&CenterDot;,\\ M_M{N}_2{s}_M\left(f_{(M-1)L+1}\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_M{N}_2{s}_M\left(f_{\mathrm{ML}}\right),\&CenterDot;\&CenterDot;\&CenterDot;,\\ M_M{N}_N{s}_M\left(f_{(M-1)L+1}\right),\&CenterDot;\&CenterDot;\&CenterDot;,M_M{N}_N{s}_M\left(f_{2L}\right)]\end{array}---\left(10\right)$

MNL * 1 dimensional vector λ is as the formula (11):

$\begin{array}{c}\mathrm{\&lambda;}=[{\mathrm{\&lambda;}}_{11}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{11}^L,{\mathrm{\&lambda;}}_{12}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{12}^L,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{1\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">M</figure-callout>}}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{1m}^L,\\ {\mathrm{\&lambda;}}_{21}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{21}^L,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{2\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">M</figure-callout>}}^1{,\&CenterDot;\&CenterDot;\&CenterDot;,\mathrm{\&lambda;}}_{2M}^L,\&CenterDot;\&CenterDot;\&CenterDot;,\\ {{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">N</figure-callout>}2}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{N2}^L,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{\mathrm{NM}}^1,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&lambda;}}_{\mathrm{NM}}^L]}^T\end{array}---\left(11\right)$

MNL * 1 dimensional vector

for obeying CN (0, σ ²i _mNL) the multiple Gaussian noise that distributes.

4) by Y _lk(f _m) by the method shown in formula (4), mate:

$T=\underset{l=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{L}{\mathrm{\&Sigma;}}}{\left|\right|S_k^{*}\left(f_m\right)Y_{\mathrm{lk}}\left(f_m\right)\left|\right|}^2---\left(4\right)$

In formula (4), ∑ represents the symbol of suing for peace, || ... || ²expression is to vector delivery, S _k(f _m) representing transmitting of transmitting submatrix k, N is the number that receives submatrix, and M is the number of transmitting submatrix, and L is the frequency number of the signal of each transmitting submatrix transmitting.The signal receiving is adjudicated while having or not, and first determines thresholding δ, if receive the coupling output energy of signal || and Y|| ²(being the T value in formula (4)) is greater than thresholding δ, adjudicates and in search coverage, has target; Otherwise there is not target in judgement.

MIMO detecting device based on NP criterion is provided by following formula (12):

$T_{\mathrm{MIMO}}={\left|\right|Y\left|\right|}^2\underset{\underset{{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="HDA0000438086730000011.png,HDA0000438086730000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_0}{<}}{\overset{\stackrel{{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">H</figure-callout>}}_1}{>}}{\mathrm{}}}\mathrm{\&delta;}---\left(12\right)$

According to above-mentioned multiple Gaussian noise and the statistical property of scattering coefficient of equal value, test statistics || Y|| ²obey

Wherein, M ₀=M _k, k=1,2 ..., M, N ₀=N _l, l=1,2 ..., N.Thresholding δ is according to false-alarm probability P _fa(in the non-existent situation of target, being mistaken for the probability of existence) chosen, according to formula (14),

$P_{\mathrm{fa}}=\mathrm{Pr}(T>\mathrm{\&delta;}|H_0)=\mathrm{Pr}(\frac{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{2}{\mathrm{\&chi;}}_{2\mathrm{<figure-callout\; id="2"\; label="LMN"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">LMN</figure-callout>}}^2>\mathrm{\&delta;})=\mathrm{Pr}({\mathrm{\&chi;}}_{2\mathrm{<figure-callout\; id="2"\; label="LMN"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">LMN</figure-callout>}}^2>\frac{2\mathrm{\&delta;}}{{\mathrm{\&sigma;}}_n^2})---\left(14\right)$

Obtain formula (15):

$\mathrm{\&delta;}=\frac{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000438086730000022.png,HDA0000438086730000041.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{2}{F}_{{\mathrm{\&chi;}}_{2\mathrm{LMN}}^2}^{-1}(1-P_{\mathrm{fa}})---\left(15\right)$

Available detection probability P now _d(probability that correct judgement target exists in the situation that target exists) is for as the formula (16):

$P_d=1-F_{{\mathrm{\&chi;}}_{2\mathrm{LMN}}^2}\left\{\frac{{\mathrm{\&sigma;}}_n^2}{[\frac{E}{M}\frac{{\left(M_0{N}_0\right)}^2}{L}+{\mathrm{\&sigma;}}_n^2]}{F}_{{\mathrm{\&chi;}}_{2\mathrm{LMN}}^2}^{-1}(1-P_{\mathrm{fa}})\right\}---\left(16\right)$

The environment shown in Fig. 2 of take below illustrates the inventive method as example:

As shown in Figure 1, at transmitting terminal, arrange 2 transmitting submatrixs, be numbered 1,2; Each transmitting submatrix comprises 3 transmitting transducer array elements, is numbered 1,2,3; The inner adjacent transmission transducer of each transmitting submatrix array element spacing is d _k=0.075m, between transmitting submatrix, spacing is d _t=4m.An output with the NI equipment of 6 paths is connected to the power amplifier of 6 paths, and 6 tunnel output channels of power amplifier are connected to the input end of 6 transmitting transducer array elements.

The long linear goal of 1.5m is positioned at R=22m place, meets

distributed condition.

At receiving end, arrange that 1 receives submatrix, receive submatrix and comprise 14 nautical receiving set array elements, be numbered 1,2 ..., 14, adjacent nautical receiving set array element spacing is d _l=0.075m.

Signal sampling frequency f _s=50kHz, signal duration T=10ms, signal time point value is t=0,1/fs ..., (T-1/fs).

Sight 1: signal frequency is f ₁=8kHz and f ₂the pure-tone polse of=6kHz (PCW) signal, interior 3 array elements of transmitting submatrix 1 transmit respectively

Interior 3 array elements of transmitting submatrix 2 transmit respectively

Sight 2: signal frequency is linear frequency modulation (LFM) signal of 6～8kHz and 8～10kHz, interior 3 array elements of transmitting submatrix 1 are at moment t _otransmit respectively

Interior 3 array elements of transmitting submatrix 2 transmit respectively

Wherein,

expression is got real part to plural number, is cos() cosine function, d ₁=0.075m, c ≈ 1450m/s, θ ₁≈ 15 ⁰, i represents imaginary number; d ₂=0.075m, θ ₂≈-15 ⁰

Environment as shown in Figure 2 forms by three layers: aqueous medium layer, sedimentary deposit and water-bed layer.Wherein, the depth of water is 21.53m, and density is ρ=1.0g/cm ³sound speed profile is provided by Fig. 2 (a), can find out at the water surface, sonic velocity change is rapider, there is larger negative gradient, the velocity of sound environment such as below depth of water 10m, can substantially regard as, under velocity of sound environment, transmit that to be irradiated to the energy of target stronger waiting, be conducive to improve the detection performance to target.Deposit thickness is 7.343m, and density is ρ=2.2g/cm ³, the velocity of sound is c _s=1624.3m/s.The bottom is homogeneous half space, and density is ρ=3.0g/cm ³, the velocity of sound is c _s=1792.4m/s.

No. 14 nautical receiving sets receive and are converted into electric signal after echo and pass to signal collecting device and gather storage, are designated as r (t).Receive signal and first by Beam-former, obtain reception array gain, obtain x (t)=α (θ) r (t), owing to there being the two expansions of time delay Doppler in underwater acoustic channel, for actionless target (ignoring Doppler's impact), adopt copy coherent integration detecting device (RCI) to consider the target echo of passing back due to multipath.?

$y\left(n\right)=\underset{j=0}{\overset{J-1}{\mathrm{\&Sigma;}}}{\left|\sqrt{\frac{2}{I}}\underset{i=0}{\overset{I-1}{\mathrm{\&Sigma;}}}{s}^{*}\left(i\right)x(i+j+n)\right|}^2---\left(15\right)$

By correspondence position being exported to energy value and aimless output energy value around, compare target is had or not and adjudicated.In target location the unknown and interfering energy, less in the situation that, also can find out energy output position corresponding to maximal value by this technology and realize the positioning function to target.

Traditional phased array, realizes a position the sensing transmitting of target and realizes the sensing of target is received a position.Take one of them transmitting submatrix being comprised of 3 transmitting transducer array elements is example, 8kHz pure-tone polse (PCW) signal of transmitting 10ms, or 6～8kHz linear frequency modulation (LFM) signal of transmitting 10ms, and amplitude is all original amplitude

doubly.Receiving array still adopts the single horizontal array on 14 tunnels, and disposal route is consistent with Phased-MIMO array processing method.

From Fig. 3, Fig. 4, can find out the position that two kinds of Sonar system can estimating target: target actual position, at R=22m, adopts the Phased-MIMO system estimation value of PCW signal to be

phased-Array system estimation value is

adopt the Phased-MIMO system estimation value of LFM signal to be

phased-Array system estimation value is

in the situation that maximum instantaneous power is limited, increase the pulsewidth transmitting and can improve transmit signal energy, improve the input signal-to-noise ratio of receiver, thereby improve the detection performance of receiver, the increase of pulsewidth has increased the blur level of adjusting the distance and estimating simultaneously.LFM signal can well solve this contradiction, so comparison diagram 3 and Fig. 4 can find out that LFM signal is larger than the result resolution of PCW signal to the matching result of target location.The relevant matches of two kinds of systems output peak value relatively simultaneously, (b) can see that the output peak value of Phased-MIMO system in target location that adopts PCW signal is 2.56 * 10 from Fig. 3 (a) ⁶, being greater than the output peak value of Phased-Array system in target location (is 1.034 * 10 ⁶), clearly, this is because Phased-MIMO system acquisition arrives the diversity gain of target to difference.

Claims (1)

1. the object detection method based on distributed Phased-MIMO Combined Treatment, is characterized in that, comprises the steps:

1) at transmitting terminal, arrange M transmitting submatrix, each is launched submatrix and comprises M _kindividual transmitting transducer array element; Each transmitting transducer array element in each transmitting submatrix is connected with the output terminal of power amplifier, and the input end of described power amplifier is connected with the output terminal of corresponding signal generating apparatus; Each is launched transmitting transducer array element in submatrix and is arranged to the minimum value of the half-wavelength transmitting that spacing between even linear array and adjacent transmission transducer array element is less than or equal to the transmitting submatrix at place; Each spacing of launching between submatrix meets the requirement shown in formula (1):

$d_t>\frac{R_t{\mathrm{\&lambda;}}_{\max }}{D}---\left(1\right)$

At receiving end, arrange that N receives submatrix, each receives submatrix and comprises N _lindividual nautical receiving set array element; Each receives nautical receiving set array element in submatrix and is connected with signal collecting device accordingly, and each receives nautical receiving set array element in submatrix and is arranged to the minimum value that spacing between even linear array and adjacent nautical receiving set array element is less than or equal to the half-wavelength transmitting accordingly; Each spacing receiving between submatrix meets the requirement shown in formula (2):

$d_r>\frac{R_r{\mathrm{\&lambda;}}_{\max }}{D}---\left(2\right)$

Wherein, M is more than or equal to 1 positive integer, M _kfor be more than or equal to 1 positive integer and

r _trepresent that the corresponding transmitting submatrix of transmitting terminal is to the distance of target's center, D represents the size of target, d _trepresent the spacing between adjacent transmitting submatrix, d _rrepresent the spacing between adjacent reception submatrix, λ _maxthe maximal value that represents all wavelength that transmit; N represents to be more than or equal to 1 positive integer, N _lrepresent to be more than or equal to 1 positive integer and r _rrepresent that the corresponding reception submatrix of receiving end is to the distance of target's center;

2) described in each, signal generating apparatus generation transmits

Wherein, E represents the gross energy transmitting,

M represents to launch the number of submatrix,

$a_t^k({\mathrm{\&theta;}}_k,f_m)={[1,e^{-i2\mathrm{\&pi;}{f}_m\frac{d_k}{c}\sin {\mathrm{\&theta;}}_k},\&CenterDot;\&CenterDot;\&CenterDot;,e^{-i2\mathrm{\&pi;}{f}_m\frac{d_k}{c}\sin {\mathrm{\&theta;}}_k(M_k-1)}]}^T,$ Wherein, [... ] ^ttransposition symbol, θ _kthe angle of arrival that target's center arrives transmitting submatrix k, k=1,2 ..., M, f _mm frequency of the signal of transmitting submatrix k transmitting, m=1,2 ... L, L is the frequency number of the signal of each transmitting submatrix transmitting, c is the velocity of propagation transmitting, d _kthe spacing between the adjacent transmission transducer array element in transmitting submatrix k, M _kbe the transmitting transducer array element number that transmitting submatrix k comprises, i represents imaginary number;

{ S _k(f _m) represent transmitting of transmitting submatrix k, ‖ S _k(f _m) ‖ ²=1/L,

Described in each, signal generating apparatus transmits

after amplifying by power amplifier, sending each transmitting transducer array element in corresponding transmitting submatrix to converts acoustic signals to and is transmitted into wish and surveys waters;

3) respectively receive submatrix by the S that transmits of the corresponding transmitting submatrix receiving _k(f _m) echo R _lk(f _m) sending corresponding signal collecting device to, described signal collecting device is to received echo R _lk(f _m) carry out received beam as the formula (3) and form:

$Y_{\mathrm{lk}}\left(f_m\right)=(b_r^l({\mathrm{\&theta;}}_l,f_m){)}^H{R}_{\mathrm{lk}}\left(f_m\right)---\left(3\right)$

In formula (3), (...) ^hconjugate transpose symbol,

$b_r^l({\mathrm{\&theta;}}_l,f_m)={[1,e^{-i2\mathrm{\&pi;}{f}_m\frac{d_l}{c}\sin {\mathrm{\&theta;}}_l},\&CenterDot;\&CenterDot;\&CenterDot;,e^{-i2\mathrm{\&pi;}{f}_m\frac{d_l}{c_l}\sin {\mathrm{\&theta;}}_l(N_l-1)}]}^T,$ Wherein, θ _lthat target's center arrives the angle of arrival that receives submatrix l, l=1,2,, N, d _lthe spacing between the adjacent nautical receiving set array element receiving in submatrix l, N _lbe to receive the nautical receiving set array element number that submatrix l comprises, i represents imaginary number;

By Y _lk(f _m) by the method shown in formula (4), mate:

$T=\underset{l=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{L}{\mathrm{\&Sigma;}}}{\left|\right|S_k^{*}\left(f_m\right)Y_{\mathrm{lk}}\left(f_m\right)\left|\right|}^2---\left(4\right)$

In formula (4), ∑ represents the symbol of suing for peace, || ... || ²expression is to vector delivery, S _k(f _m) representing transmitting of transmitting submatrix k, N is the number that receives submatrix, and M is the number of transmitting submatrix, and L is the frequency number of the signal of each transmitting submatrix transmitting;

By target's center to all distance R that respectively receive submatrix _lcorresponding T value is depicted as R _l-T two dimensional image; Then observe R _l-T two dimensional image, if there is peak value in target's center to receiving between submatrix, shows to exist target.

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