CN103713289B - Based on the object detection method of distributed Phased-MIMO Combined Treatment - Google Patents

Abstract

The invention discloses a kind of object detection method based on distributed Phased-MIMO Combined Treatment.The method is by being arranged in different positions in a distributed manner by multiple submatrix, the inner formation by launching beam of submatrix launches coherent signal acquisition coherent gain, between submatrix, the mutually orthogonal target diverse location that is irradiated to of signal obtains target diversity, and receiving array is formed by received beam and detects realization of goal with matched filtering.The inventive method can obtain relevant and incoherent gain, and eliminates interference, suppression reverberation, anti-target glint characteristic.In distributed object, when the beam angle of submatrix is greater than target size, detection perform is better than traditional phased array.

Description

Based on the object detection method of 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 affecting active probe is reverberation.Reverberation and target echo all cause by transmitting, and its spectral property correlativity when 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 result also in the flicker instability of active sonar detection performance, and the emission array in single base is difficult to for the interference of distributed target and signal the stability ensureing the detection of a target.

In 10 years of past, multiple-input and multiple-output (MultipleInputMultipleOutput is called for short " MIMO ") technology is rapid in the research and development of field of radar.Traditional phased array carries out signal driving the diversity gain launched and can obtain emission array, realizes the effective focusing illumination to target, thus reaches anti-reverberation, reduce the object of disturbing effect.Meanwhile, distributed mimo system can obtain transmitted waveform diversity and target diversity due to it, is also widely used in target detection with location.But due to the time delay of underwater acoustic channel and the two expansion of Doppler, MIMO technology is slower in the development in sonar field.2006, I.Bekkerman and J.Tabrikian proposed radar and the unified MIMO process framework of sonar first.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, for existing single base active sonar Detection Techniques Problems existing, to 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) arrange that M is launched submatrix at transmitting terminal, each submatrix of launching 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; Transmitting transducer array element in each transmitting submatrix is arranged to even linear array and spacing between adjacent transmission transducer array element is less than or equal to the minimum value of the half-wavelength transmitted of the transmitting submatrix at place; Spacing between each transmitting submatrix meets the requirement shown in formula (1):

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

Arrange N number of reception submatrix at receiving end, each reception submatrix comprises N _lindividual nautical receiving set array element; Nautical receiving set array element in each reception submatrix is connected with corresponding signal collecting device, and each nautical receiving set array element received in submatrix is arranged to even linear array and spacing between consecutive hydrophones array element is less than or equal to the minimum value of the half-wavelength transmitted accordingly; Spacing between each reception submatrix meets the requirement shown in formula (2):

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

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

2) each described signal generating apparatus produces and transmits wherein, E represents the gross energy transmitted,

M represents the number of launching submatrix,

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

{ S _k(f _m) represent and launch transmitting of submatrix k, || S _k(f _m) || ²=1/L, j ∈ 1,2 ..., M} and j ≠ k.

Transmitting of each described signal generating apparatus send to after being amplified by power amplifier and corresponding launch each transmitting transducer array element in submatrix and convert acoustic signals to and be transmitted into for detection waters;

3) each S that transmits of corresponding transmitting submatrix receiving submatrix and will receive _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 being formed such as formula the received beam shown in (3):

$Y_k\left(f_m\right)={\left(b_r^l({\mathrm{\θ}}_l,f_m)\right)}^H{R}_{lk}\left(f_m\right)---\left(3\right)$

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

$b_r^l({\mathrm{\θ}}_l,f_m)={\[1,e^{-i2{\mathrm{\πf}}_m\frac{d_l}{c}{\mathrm{sin\θ}}_l},\mathrm{...},e^{-i2{\mathrm{\πf}}_m\frac{d_l}{c}{\mathrm{sin\θ}}_l(M_l-1)}\]}^T,$ Wherein, θ _lthat target's center arrives the angle of arrival receiving submatrix l, l=1,2, N, d _lreceive the spacing between the consecutive hydrophones array element in submatrix l, N _lbe the nautical receiving set array element number that reception submatrix l comprises, i represents imaginary number;

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

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

In formula (4), ∑ represents summation symbol, || ... || ²represent vector delivery, S _k(f _m) represent and launch transmitting of submatrix k, N is the number receiving submatrix, and M is the number of launching submatrix, and L is the frequency number of the signal that each transmitting submatrix is launched;

By the distance R of target's center to all each reception submatrixs _lcorresponding T value is depicted as R _l-T two dimensional image; Then R is observed _l-T two dimensional image, if the heart exists peak value between reception submatrix in the target, then shows to there is 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, acquisition certain resolving power thus suppress reverberation interference while, obtain target diversity information thus reach anti-target glint characteristic, stablizing active sonar detection performance.Numerical simulation and experimental verification are distributed object in target, and when high s/n ratio, Phased-MIMO active target Detection Techniques are due to traditional phased array Detection Techniques.

Accompanying drawing explanation

Fig. 1 is emission array and the receiving array schematic diagram of structuring the formation relative to target;

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

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

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

Embodiment

The inventive method comprises the steps:

1) transmitting terminal arrange M transmitting submatrix, be numbered 1 .., M, M be more than or equal to 1 positive integer.Kth (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 the distance of transmitting terminal to 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.The inside of submatrix is launched, the spacing d between adjacent transmission transducer array element in kth _kbe less than or equal to the minimum value that kth launches the half-wavelength transmitted of submatrix, the spacing between adjacent transmission submatrix is d _tmeet the requirement shown in formula (1):

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

Arrange N number of reception submatrix at receiving end, be numbered 1 .., N, N represent the positive integer being more than or equal to 1.L (l=1,2 ..., N) individual reception submatrix comprises N _lindividual nautical receiving set array element, N _lrepresent be more than or equal to 1 positive integer and r _rrepresent the distance of receiving end to target's center.The spacing d of the consecutive hydrophones array element of l reception submatrix inside _lbe less than or equal to the minimum value that l 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):

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

Kth (k=1,2 ..., M) q in individual transmitting submatrix (q=1,2 ..., M _k) m frequency signal launching of individual transmitting transducer array element be wherein, [... ] ^ttransposition symbol, θ _kthat target's center arrives the angle of arrival launching submatrix k, k=1,2 ..., M, f _mm the frequency of launching the signal that submatrix k launches, m=1,2 ... L, L are the frequency numbers of the signal that each transmitting submatrix is launched, and c is the velocity of propagation transmitted, d _klaunch the spacing between the adjacent transmission transducer array element in submatrix k, || S _k(f _m) || ²=1/L, m=1,2 ... L, j ∈ 1,2 ..., M} and j ≠ k.Being write as vector form is wherein for kth launches submatrix at frequency f _mpoint to the driving vector of target's center.

Corresponding l the signal frequency receiving the kth transmitting submatrix transmitting that p nautical receiving set array element in submatrix receives is f _mecho can be expressed as:

$r_{lk,p}\left(f_m\right)={\mathrm{\α}}_k^m{\mathrm{\ϵ}}_k^m{\mathrm{\ζ}}_l^m{M}_k\sqrt{E/M}{s}_k\left(f_m\right)e^{-i2{\mathrm{\πf}}_m\frac{d_l}{c}{\mathrm{sin\θ}}_l(p-1)}+n_{lk,p}^m---\left(5\right)$

Wherein, m the frequency launching submatrix transmitting for kth is irradiated to the scattering coefficient of equal value after scatterer; represent and launch the transmission loss (TL) of submatrix to target, represent respectively and launch submatrix to target, target is to the transmission loss (TL) receiving submatrix; Being write as vector form is:

$r_{lk}\left(f_m\right)={\mathrm{\α}}_k^m{\mathrm{\ϵ}}_k^m{\mathrm{\ζ}}_l^m{M}_k\sqrt{E/M}{s}_k\left(f_m\right)a_r^l({\mathrm{\θ}}_l,f_m)+n_{lk}^m---\left(6\right)$

for target's center receives submatrix at frequency f to l _mresponse vector; the multiple noise of Gauss for zero-mean.

3) for the S that transmits of corresponding transmitting submatrix that each reception submatrix will receive _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 being formed such as formula the received beam shown in (3):

$Y_k\left(f_m\right)={\left(b_r^l({\mathrm{\θ}}_l,f_m)\right)}^H{R}_{lk}\left(f_m\right)---\left(3\right)$

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

$b_r^l({\mathrm{\θ}}_l,f_m)={\[1,e^{-i2{\mathrm{\πf}}_m\frac{d_l}{c}{\mathrm{sin\θ}}_l},\mathrm{...},e^{-i2{\mathrm{\πf}}_m\frac{d_l}{c}{\mathrm{sin\θ}}_l(M_l-1)}\]}^T,$ Wherein, θ _lthat target's center arrives the angle of arrival receiving submatrix l, l=1,2, N, d _lreceive the spacing between the consecutive hydrophones array element in submatrix l, N _lbe the nautical receiving set array element number that reception submatrix l comprises, i represents imaginary number;

4) step 3) the process data that obtain can be expressed as:

$\begin{array}{c}{Y}_k\left(f_m\right)={\left(a_r^l\right({\mathrm{\θ}}_l,f_m\left)\right)}^H\left({\mathrm{\α}}_k^m{\mathrm{\ϵ}}_k^m{\mathrm{\ζ}}_l^m{M}_k\sqrt{E/M}{s}_k\right(f_m)a_r^l({\mathrm{\θ}}_l,f_m)+n_{lk}^m)\\ {\mathrm{\α}}_k^m{\mathrm{\ϵ}}_k^m{\mathrm{\ζ}}_l^m{M}_k{N}_l\sqrt{E/M}{s}_k\left(f_m\right)v_{lk}^m\end{array}---\left(7\right)$

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

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

Namely the matrix form of formula (8) is such as formula shown in (9):

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

Wherein, MNL × MNL ties up diagonal matrix Q such as formula shown in (10):

Q＝diag[M ₁N ₁s ₁(f ₁),...,M ₁N ₁s ₁(f _L),

M ₂N ₁s ₂(f _L+1),...,M ₂N ₁s ₂(f _L+L),…,

M _MN ₁s _M(f _(M-1)L+1),...,M _MN ₁s ₂(f _ML),(10)

M ₁N ₂s ₁(f ₁),...,M ₁N ₂s ₁(f _L),…,

M _MN ₂s _M(f _(M-1)L+1),...,M _MN ₂s _M(f _ML),…,

M _MN _Ns _M(f _(M-1)L+1),...,M _MN _Ns _M(f _2L)]

MNL × 1 dimensional vector λ is such as formula shown in (11):

$\begin{array}{c}\mathrm{\λ}=\[{\mathrm{\λ}}_{11}^1,\mathrm{...},{\mathrm{\λ}}_{11}^L,{\mathrm{\λ}}_{12}^1,\mathrm{...},{\mathrm{\λ}}_{12}^L,\mathrm{...},{\mathrm{\λ}}_{1M}^1,\mathrm{...},{\mathrm{\λ}}_{1M}^L\\ {\mathrm{\λ}}_{21}^1,\mathrm{...},{\mathrm{\λ}}_{21}^L,\mathrm{...},{\mathrm{\λ}}_{2M}^1,\mathrm{...},{\mathrm{\λ}}_{2M}^L,\mathrm{...},\\ {\mathrm{\λ}}_{N2}^1,\mathrm{...},{\mathrm{\λ}}_{N2}^L,{\mathrm{\λ}}_{NM}^1,\mathrm{...},{\mathrm{\λ}}_{NM}^L{\]}^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) mate by the method shown in formula (4):

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

In formula (4), ∑ represents summation symbol, || ... || ²represent vector delivery, S _k(f _m) represent and launch transmitting of submatrix k, N is the number receiving submatrix, and M is the number of launching submatrix, and L is the frequency number of the signal that each transmitting submatrix is launched.The signal received carry out adjudicating with or without time, first determine thresholding δ, if the coupling of Received signal strength exports energy || Y|| ²(the T value namely in formula (4)) is greater than thresholding δ, then adjudicate in search coverage and there is target; Otherwise there is not target in judgement.

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

$T_{MIMO}=\left|\right|Y|{|}^2\begin{array}{c}{H}_1\\ >\\ <\\ H_0\end{array}\mathrm{\&delta;}---\left(12\right)$

According to the statistical property of above-mentioned multiple Gaussian noise and 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 namely mistaken for the probability of existence) is chosen, namely according to formula (14),

$P_{fa}=\mathrm{Pr}(T>\mathrm{\&delta;}|H_0)=\mathrm{Pr}(\frac{{\mathrm{\&sigma;}}_n^2}{2}{\mathrm{\&chi;}}_{2LMN}^2>\mathrm{\&delta;})=\mathrm{Pr}({\mathrm{\&chi;}}_{2LMN}^2>\frac{2\mathrm{\&delta;}}{{\mathrm{\&sigma;}}_n^2})---\left(14\right)$

Obtain formula (15):

$\mathrm{\&delta;}=\frac{{\mathrm{\&sigma;}}_n^2}{2}{F}_{{\mathrm{\&chi;}}_{2LMN}^2}^{-1}(1-P_{fa})---\left(15\right)$

Now available detection probability P _d(namely depositing the probability of correctly adjudicating target in case and existing in target) is for such as formula shown in (16):

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

The inventive method is illustrated below for the environment shown in Fig. 2:

As shown in Figure 1, arrange that 2 are launched submatrix, are numbered 1,2 at transmitting terminal; Each transmitting submatrix comprises 3 transmitting transducer array elements, is numbered 1,2,3; Each transmitting submatrix inner adjacent transmission transducer array element distance is d _k=0.075m, launching spacing between submatrix 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 linear goal of 1.5m length is positioned at R=22m place, meets distributed condition.

Arrange that 1 receives submatrix at receiving end, receive submatrix and comprise 14 nautical receiving set array elements, be numbered 1,2 ..., 14, consecutive hydrophones array element distance is d _l=0.075m.

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

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

Launch interior 3 array elements of submatrix 2 to transmit respectively

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

Launch interior 3 array elements of submatrix 2 to transmit respectively

Wherein, represent and get real part to plural number, cos () is 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 substantially can to regard as at below depth of water 10m, waiting, the energy that is irradiated to target of transmitting under velocity of sound environment is comparatively strong, is conducive to improving the detection perform 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.

Be converted into after No. 14 nautical receiving sets receive echo electric signal pass to signal collecting device carry out collection store, be designated as r (t).First Received signal strength is obtained by Beam-former and receives array gain, obtain x (t)=α (θ) r (t), owing to there is the two expansion of delay-Doppler in underwater acoustic channel, for actionless target (namely ignoring Doppler contribution), copy coherent integration detecting device (RCI) is adopted to consider the target echo passed back due to multipath.Namely

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

By correspondence position being exported energy value and the aimless output energy value of surrounding compares target with or without adjudicating.When target location is unknown and interfering energy is less, also find out by this technology the positioning function that position corresponding to Energy transmission maximal value realize target.

Traditional phased array, namely realizes a position launching the sensing of target and realizing receiving the sensing of target a position.The transmitting submatrix be made up of 3 transmitting transducer array elements for one of them, launches 8kHz pure-tone polse (PCW) signal of 10ms, or launches 6 ~ 8kHz linear frequency modulation (LFM) signal of 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.

As can be seen from Fig. 3, Fig. 4, two kinds of Sonar system can the position of 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 the Phased-MIMO system estimation value of employing LFM signal is phased-Array system estimation value is when maximum instantaneous power is limited, increase the pulsewidth transmitted and can improve transmit signal energy, improve the input signal-to-noise ratio of receiver, thus improve the detection perform of receiver, the increase of pulsewidth increases 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 simultaneously comparing two kinds of systems exports peak value, can see adopt the Phased-MIMO system of PCW signal to be 2.56 × 10 at the output peak value of target location from Fig. 3 (a) (b) ⁶, being greater than Phased-Array system at the output peak value of target location (is 1.034 × 10 ⁶), difference clearly, this is because Phased-MIMO system gets the diversity gain of target.

Claims (1)

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

1) arrange that M is launched submatrix at transmitting terminal, each submatrix of launching 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; Transmitting transducer array element in each transmitting submatrix is arranged to even linear array and spacing between adjacent transmission transducer array element is less than or equal to the minimum value of the half-wavelength transmitted of the transmitting submatrix at place; Spacing between each transmitting submatrix meets the requirement shown in formula (1):

Arrange N number of reception submatrix at receiving end, each reception submatrix comprises N _lindividual nautical receiving set array element; Nautical receiving set array element in each reception submatrix is connected with corresponding signal collecting device, and each nautical receiving set array element received in submatrix is arranged to even linear array and spacing between consecutive hydrophones array element is less than or equal to the minimum value of the half-wavelength transmitted accordingly; Spacing between each reception submatrix meets the requirement shown in formula (2):

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

2) each described signal generating apparatus produces and transmits wherein, E represents the gross energy transmitted,

M represents the number of launching submatrix,

wherein, [... ] ^ttransposition symbol, θ _kthat target's center arrives the angle of arrival launching submatrix k, k=1,2 ..., M, f _mm the frequency of launching the signal that submatrix k launches, m=1,2 ... L, L are the frequency numbers of the signal that each transmitting submatrix is launched, and c is the velocity of propagation transmitted, d _klaunch the spacing between the adjacent transmission transducer array element in submatrix k, M _kbe the transmitting transducer array element number that transmitting submatrix k comprises, i represents imaginary number;

{ S _k(f _m) represent and launch transmitting of submatrix k, || S _k(f _m) || ²=1/L, j ∈ 1,2 ..., M} and j ≠ k;

Transmitting of each described signal generating apparatus send to after being amplified by power amplifier and corresponding launch each transmitting transducer array element in submatrix and convert acoustic signals to and be transmitted into for detection waters;

3) each S that transmits of corresponding transmitting submatrix receiving submatrix and will receive _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 being formed such as formula the received beam shown in (3):

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

wherein, θ _lthat target's center arrives the angle of arrival receiving submatrix l, l=1,2 ..., N, d _lreceive the spacing between the consecutive hydrophones array element in submatrix l, N _lbe the nautical receiving set array element number that reception submatrix l comprises, i represents imaginary number;

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

In formula (4), ∑ represents summation symbol, || ... || ²represent vector delivery, S _k(f _m) represent and launch transmitting of submatrix k, N is the number receiving submatrix, and M is the number of launching submatrix, and L is the frequency number of the signal that each transmitting submatrix is launched;

By the distance R of target's center to all each reception submatrixs _lcorresponding T value is depicted as R _l-T two dimensional image; Then R is observed _l-T two dimensional image, if the heart exists peak value between reception submatrix in the target, then shows to there is target.