CN103529441A - Method and system for detecting and distinguishing passive synthetic aperture target signal - Google Patents

Abstract

The present invention provides a method and a system for detecting and distinguishing a passive synthetic aperture target signal, wherein the method comprises the following steps: step 101) constructing a motion doppler receiving model for a target signal under motion of a towed array sonar; step 102) respectively performing cross correlation averaging on target signals which are received by a hydrophone at an overlapping part on spatial position according to a passive synthetic aperture sonar algorithm when the array performs two successive motions in a fixed time interval, and then performing frequency domain wave beam forming treatment on the target signals which are received by array elements at different time periods; step 103) performing energy integration on the output sub-frequency-bands after forming of the frequency domain wave beam for obtaining wave beam output of each time interval; step 104) performing phase estimation on time delay and spatial position movement according to the doppler receiving model, and acquiring a phase correction factor according to the phase estimation; and step 105) compensating the wave beam output through each phase correction factor of time interval, and performing cross combined accumulation on the compensated wave beam output and realizing detection on the target through a time orientation process map.

Description

A kind of passive synthetic aperture target echo detection and resolution method and system

Technical field

The present invention relates to underwater sound Passive Sonar Signal detection method and drag linear array passive synthetic aperture sonar (Passive Synthetic Aperture Sonar, PSAS) technology, for the algorithm of target echo detection and resolution, relates in particular to the non-overlapped aperture of a kind of motion and drags linear array passive synthetic aperture signal detecting method and system.

Background technology

In recent years, passive sonar systems becomes more and more important to the detection of low noise target, and more and more difficult, and its detectability is along with the appearance of calm type target and fast development and be subject to serious challenge.Make a general survey of sonar development history, high-resolution and high-gain are the targets that pursue in sonar field always, for improving fractal dimension, its working frequency range is more and more lower, and improve bearing resolution under low frequency condition, mean longer hydrophone array, but the restriction due to the stability in towing process and maneuverability, it is unpractical that basic matrix length is increased to too large magnitude, passive synthetic aperture algorithm is a kind of important means of head it off, it moves to synthesize by towing line array and obtains the synthetic aperture array more much bigger than effective aperture, rely on the restriction of the motor-driven breakthrough array aperture of short battle array, obtain higher gain and higher bearing resolution.According to the target property analyses such as naval vessel under water learn the blade cutting seawater of screw propeller produce the line spectrum compositions such as simple signal component for a synthetic effective aperture more much bigger than physical pore size provides may, passive synthetic aperture sonar technique implementation method is when array moves for twice in succession, the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, as rear this underlapped nautical receiving set, receive the phase correction term of signal, what this phase correction term can be expanded for the coherent combination of wave beam in gust sequential positions output of moving drags linear array equivalent length.Due to the array movement deviation that under actual underwater complex environment, medium and path disturbance cause, conventional passive synthetic aperture sonar algorithm phase place correction-compensation is on two continuous positions fixing interval time, before and after array element aperture, not exclusively overlap, make the phase estimation factor occur even mistake of error, be that PSAS algorithm drags linear dimension algorithm to carry out having overlapping element position restricted problem in array extension as expansion, cause effectively detecting and to differentiate Underwater Target Signal.Overlapping array element (aperture) passive synthetic aperture sonar algorithm is generally used for ideally detection and the resolution of echo signal, consider the effect of complicate factors such as underwater acoustic channel, while dragging linear array to maintain constant speed with assurance continuous coverage in practical application, identical being difficult to of locus of overlapping nautical receiving set meets, do not there is feasibility, versatility and practicality, the detection of passive synthetic aperture sonar normal signal and resolution method can not be rationally applied in engineering.

Summary of the invention

The object of the invention is to, the shorter basic matrix of passive sonar towing line array application obtains gain and the resolving power of the actual physics aperture battle array of several times to tens times, realization is to effective detection of weak echo signal under water, and passive synthetic aperture technology is effectively applied in engineering reality, the invention provides a kind of passive synthetic aperture target echo detection and differentiate method and system.

To achieve these goals, the invention provides a kind of passive synthetic aperture target echo detection and resolution method, the method application passive synthetic aperture technology realizes weak echo signal under water is effectively detected, and described method comprises:

Step 101) be configured in and drag linear array to move the lower motion Doppler to echo signal to receive model;

When step 102) dragging linear array array twice motion in succession occur at interval at a fixed time according to the utilization of passive synthetic aperture sonar algorithm, it is average that the echo signal respectively nautical receiving set of lap on locus being received is done simple crosscorrelation, the echo signal that is about to receive is carried out time segment processing, analyze the reception signal of every adjacent twice time period, the echo signal then each array element of different time sections being received is carried out frequency-domain beamforming processing;

Step 103) the output frequency division band after frequency-domain beamforming is carried out to energy integral and obtain each time period wave beam output;

Step 104) by the Doppler who drags linear array to move lower structure, receive model, respectively time delay and locus are moved forward into line phase estimation, and obtain phase correction term according to the phase estimation obtaining;

Step 105) by each phase correction term of time segment for compensation process 103) wave beam output, cumulative and then acquisition course figure time aziniuth to the wave beam output coherent combination after compensation, read orientation, target place, its azimuth recording is processed and differentiated, realize the detection to target.

In technique scheme, the concrete overlapping number of the nautical receiving set of described lap is to drag half of the total number of linear array array element.

In technique scheme, described phase correction term be that time delay is estimated and locus travel(l)ing phase is estimated with.

In technique scheme, described step 102) further comprise following sub-step:

When step 102-1) dragging linear array array twice motion in succession occur at interval at a fixed time according to the utilization of passive synthetic aperture sonar algorithm, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period;

Wherein, this step also comprises the useful signal in the echo signal that adopts line spectrum to detect strategy detection reception;

Step 102-2) then each array element of different time sections is received to signal and carry out frequency-domain beamforming processing.

In technique scheme, described step 105) further comprise following sub-step:

Step 105-1) according to step 104) " phase estimation is obtained phase correction term " and the step 103 that obtain) in " each time period wave beam output ", time segment is processed, the phase correction term of each time period and the wave beam output of corresponding time period are multiplied each other and waited processing, complete " each phase correction term of time segment is for compensation process 103) wave beam export ";

Step 105-2) signal of above-mentioned each time period is superposeed, the wave beam output after compensation is carried out to coherent combination and add up and then obtain course figure time aziniuth;

Step 105-3) again course figure wave beam output time aziniuth is detected, obtain the corresponding orientation of object beam, be specially: the detection orientation that different frequency bands internal object wave beam is corresponding is carried out to record, quadratic fit is carried out in the orientation of storing in each frequency band, according to result of calculation computer azimuth estimation variance, the detection variance thresholding of the orientation estimation variance of calculating and setting is compared, if be less than thresholding, the underwater acoustic target signal result detecting is true, receive Underwater Target Signal and really contain underwater acoustic target signal, otherwise testing result is false-alarm, in the signal receiving, do not contain echo signal, detection and the location of echo signal have been combined.

Based on said method, the invention provides a kind of passive synthetic aperture target echo detection and resolution system, this system applies passive synthetic aperture technology realizes weak echo signal under water is effectively detected, and described system comprises:

Acceptance Model is set up module, for being configured in, drags linear array to move the lower motion Doppler to echo signal to receive model;

The first processing module, when dragging linear array array according to the utilization of passive synthetic aperture sonar algorithm twice motion in succession occur at interval at a fixed time, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period, then each array element of different time sections is received to signal and carry out frequency-domain beamforming processing;

The second processing module, carries out energy integral for the output frequency division band to after frequency-domain beamforming and obtains each time period wave beam output;

Space-time phase correction term acquisition module, receives model for the Doppler by dragging linear array to move lower structure, respectively time delay and locus is moved forward into line phase estimation, and obtains phase correction term according to the phase estimation obtaining; With

Motion phase error compensation and testing result output module, for each phase correction term of time segment exported for compensating described wave beam, wave beam output after compensation is carried out to coherent combination to add up and then obtains course figure time aziniuth, by its time bearing history figure, obtain the corresponding orientation of object beam, the detection and the location that complete echo signal again.

In technique scheme, the concrete overlapping number of the nautical receiving set of described lap is to drag half of the total number of linear array array element.

In technique scheme, described phase correction term be that time delay is estimated and locus travel(l)ing phase is estimated with.

In technique scheme, described the first processing module further comprises following submodule:

Time segment is processed submodule, when dragging linear array array according to the utilization of passive synthetic aperture sonar algorithm twice motion in succession occur at interval at a fixed time, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period; With

Frequency-domain beamforming submodule, carries out frequency-domain beamforming processing for each array element of different time sections is received to signal.

In technique scheme, described motion phase error compensation and testing result output module further comprise following submodule:

Motion phase error compensation submodule, for exporting each phase correction term compensation wave beam of time segment;

Coherent combination is processed submodule, carries out coherent combination add up for the wave beam output to after compensation; With

Testing result output sub-module, for by time aziniuth course figure obtain the corresponding orientation of object beam, the detection and the location that complete echo signal.

Wherein, in technique scheme, course figure observation is common method in UNDERWATER ACOUSTIC SIGNAL DETECTION time aziniuth, without repeating, be briefly described below: course figure carried out Short Time Fourier Transform by the sampled data to continuous and formed time aziniuth, divide frame to process the sample sequence of original signal and (as be divided into 100 frames, 2000 points of every frame), interframe overlapped 50%, respectively each frame signal is carried out to wave beam formation processing, obtain the corresponding target azimuth of each frame, the temporal joint of each frame is obtained to course figure time aziniuth.In a word, adopt one time aziniuth course figure can read orientation, target place, its azimuth recording is carried out to follow-up process of fitting treatment and thresholding and differentiates, can realize the effective detection to target.

In sum, the invention provides a kind of a kind of detection and resolution method of dragging linear array passive synthetic aperture echo signal based on the non-overlapped aperture of motion that propose, the method is avoided because complicated Underwater Acoustic Environment impact makes tow line array be difficult to maintain constant speed, then in the time of can not guaranteeing continuous coverage, the locus of overlapping nautical receiving set is identical, before and after the non-overlapped aperture PSAS algorithm proposing moved for twice in the adjacent time interval, array element need not overlap completely, and utilizing respectively time delay and locus to move equiphase modifying factor can fine compensation motion phase error.Described scheme comprises the specificity analysis of the target radiated noise such as naval vessel under water and drags linear array to move the structure that lower motion Doppler receives signal model, consideration echo signal can utilize line spectrum detection technique useful signal to be detected, described method can utilize frequency-domain beamforming to be processed, conventionally for broadband signal, analyze, extract signal in this frequency range, then obtain wave beam output, while receiving due to array motion can there is Doppler shift in target frequency simultaneously, the error that when concrete consideration linear array receives signal, Doppler frequency domain is brought, the non-overlapped aperture of described motion drags linear array passive synthetic aperture signal detecting method can be directly used in phase delay compensation, need not consider that array element is mutually completely overlapping.

Compared with prior art, proposed by the inventionly a kind ofly based on the non-overlapped aperture of motion, drag the detection of linear array passive synthetic aperture echo signal and resolution method to have the following advantages:

On the one hand, the method is without knowing the position angle of signal source, definite frequency and towed array speed accurately, by phase estimation, compensate and revise the reception data that can synthesize nautical receiving set, without guaranteeing that element position must overlap completely, by time delay and locus, move and can obtain the phase place correction-compensation factor, passive synthetic aperture algorithm application is not subject to the constrained of aperture location in input, at Beam Domain, replace its enterprising line phase correction in array element territory, is directly used in phase place correction-compensation;

On the other hand, in conjunction with to the analysis of the target radiated noise characteristics such as naval vessel under water and drag linear array to move the structure that lower motion Doppler receives signal model, wherein analyze ship noise characteristic not only for the passive synthetic aperture technology of underwater propeller cutting formation line spectrum signal lays the foundation, and to technology such as towboat noise cancellations, provide theoretical reference for follow-up signal detects; The Doppler that array moves receives signal model structure signal formation, array element mobile reception etc. is made to clear understanding, and the integrated array of clearer and more definite passive synthetic aperture receives signal formation and phase place correction-compensation method;

Secondly, the error that while receiving signal containing linear array in described scheme, Doppler frequency domain is brought, consider its time delay, move locus, the phase place that the factors of influence such as Doppler shift bring is inconsistent, due to time delay and locus move if guarantee the adjacent time interval move before and after twice array have over half aperture length of array length and overlap and can do correction-compensation to it, needn't refinement consider that array moves coincidence position, more needn't require array aperture to overlap completely, avoid the detection signal target azimuth out of true that does not overlap completely and cause due to element position movement deviation aperture, dragging linear array to move middle reception signal time segment processes, to different time sections, drag each array element of linear array basic matrix to receive signal and carry out frequency-domain beamforming processing, and the output frequency division band after frequency-domain beamforming is carried out to energy integral can obtain wave beam output,

Finally, because the non-overlapped motion in aperture is dragged linear array passive synthetic aperture signal detecting method and can be directly used in phase delay compensation, need not consider that array element is mutually completely overlapping, apply gain and resolving power that shorter basic matrix obtains the actual physics aperture battle array of several times to tens times, detectability to weak echo signal is under water excellent, speed, it has certain engineering practicability.

Accompanying drawing explanation

Fig. 1 is that the present invention utilizes horizontal line array the radiated noise of submarine target to be carried out to the sketch of walkaway;

Fig. 2 of the present inventionly drags linear array array element to move overlapping (aperture is completely not overlapping) passive synthetic aperture schematic diagram based on motion;

Fig. 3 is that the non-overlapped aperture of motion is dragged linear array passive synthetic aperture input and differentiated method flow diagram

Embodiment

Below in conjunction with the drawings and specific embodiments, elaborate the method in aperture the incomplete workflow of phase place correction-compensation when overlapping.

The present invention proposes a kind of detection and resolution method of dragging linear array passive synthetic aperture echo signal based on the non-overlapped aperture of motion, avoid because complicated Underwater Acoustic Environment impact makes tow line array be difficult to maintain constant speed, then in the time of can not guaranteeing continuous coverage, the locus of overlapping nautical receiving set is identical, the non-overlapped aperture PSAS algorithm proposing needn't require the adjacent time interval move for twice before and after array element overlap completely, utilizing respectively time delay and locus the correction of space-time unite phase place such as to move can fine compensation motion phase error.The invention provides a kind of passive synthetic aperture algorithm and can be directly used in phase delay compensation, need not consider that array element is mutually completely overlapping, excellent to the detectability of weak echo signal under water, speed, it has certain engineering practicability.

To achieve these goals, the invention provides the non-overlapped aperture of a kind of motion and drag linear array passive synthetic aperture target echo detection and resolution method, it is characterized in that considering in the complicated Underwater Acoustic Environment of the actual underwater sound drags linear array to move irregular causing in the not exclusively overlapping situation in array element aperture, can effectively detect weak echo signal under water, described method comprises following steps:

Step (1) be take under water the target radiated noise specificity analysis such as naval vessel and is received model dragging linear array to move lower motion Doppler as base configuration signal;

Step (2) is building on the basis of Signal reception model, and consideration will drag linear array to move the middle actual signal that receives to carry out time segment processing, drag each array element of linear array basic matrix to receive signal carry out frequency-domain beamforming processing to different time sections;

The output frequency division band of step (3) after to step (2) frequency-domain beamforming carries out energy integral and obtains wave beam output;

Step (4) is estimated to the time delay causing due to time segment processing in step (2) and step (3) and because locus moves forward into line phase respectively;

Step (5) is by each phase correction term of time segment in step (4) for step (3) wave beam output compensation, and coherent combination output obtains the corresponding orientation of object beam, realizes the effective detection to echo signal.

In technique scheme, the error that when described step (2) and step (3) are also considered linear array reception signal, Doppler frequency domain is brought, consider time delay, move locus, the phase place that the factors of influence such as Doppler shift bring is inconsistent, due to time delay and locus move if guarantee the adjacent time interval move before and after twice array have over half aperture length of array length and overlap and can do correction-compensation to it, needn't refinement consider that array moves coincidence position, more needn't require array aperture to overlap completely, avoid the detection signal target azimuth out of true that does not overlap completely and cause due to element position movement deviation aperture.

In technique scheme, described step (1) further comprises the analysis of ship noise under water and drags linear array to move the structure that lower motion Doppler receives signal model: wherein analyze ship noise characteristic not only for the passive synthetic aperture technology that underwater propeller cutting forms line spectrum signal lays the foundation, and to technology such as towboat noise cancellations, provide theoretical reference for follow-up signal detection; The Doppler that array moves receives signal model and builds signal formation, array element mobile reception etc. is made to clear understanding, for the integrated array of passive synthetic aperture receives signal analysis and phase compensation indicates thinking.

The mechanical noise of hull, propeller noise and hydrodynamic noise are three kinds of main sources of naval vessel ship noise, and wherein mechanical noise and propeller noise are the main sound source of ship noise.Mechanical noise is the various mechanical vibration on navigation or industry naval vessel, the noise forming to radiation in water by hull, due to the difference of various mechanical motion forms, the underwater radiation noise character of its generation is also just different, and this noise can be regarded the superposition of strong line spectrum and weakly continuous spectrum as; Propeller noise is the noise by the screw propeller institute radiation of rotating, and comprises the noise that Propeller Cavitation Noise and propeller blade vibration produce, often the major part of ship-radiated noise high band; Hydrodynamic noise is flow through motion marine surfaces and is formed by ocean current irregular, that rise and fall, is the result that flow dynamic acts on naval vessel, aspect intensity, generally by mechanical noise and propeller noise, is covered.

Warship radiated noise spectral property and frequency, the speed of a ship or plane, the degree of depth are relevant under water, and the low frequency end of composing during the low speed of a ship or plane is mainly mechanical noise and propeller blade speed spectral line, and along with increase frequency, this spectral line reduces brokenly; When the speed of a ship or plane is higher, the continuous spectrum of Propeller Cavitation Noise is even more important, has covered a lot of line spectrums.Total power spectrum of ships radiated noise signal can be write as broadband continuous spectrum and line spectrum and:

G(t,f)=G _s(f)+G _L(f)+2m(t)m(f)G _s(f)

G in formula _s(f) represent stable and continuous power spectrum, G _l(f) represent line spectrum part, 2m (t) m (f) G _s(f) represent non-stationary time varying spectrum, m (t) and m (f) are respectively modulating function and depth of modulation spectrum.For ship-radiated noise, under the given speed of a ship or plane and the degree of depth, the principal ingredient of spectrum is relevant with threshold frequency, common naval vessel threshold frequency is between 100 ~ 1000Hz, during lower than this frequency, the machinery of ship and the line spectrum of screw propeller during the principal ingredient of spectrum, during higher than this frequency, the principal ingredient of spectrum is the continuing noise spectrum of propeller cavitation.According to research, show, the frequency domain characteristic of ship-radiated noise is the superposition of broadband continuous spectrum and arrowband line spectrum, and arrowband spectral line mainly concentrates on below 1kHz, and broadband continuous spectrum has covered a plurality of octaves.

In actual measurement, because echo signal and Receiving Array Hydrophone move mutually, there is Doppler signal Receiver Problem.Fig. 1 (seeing accompanying drawing explanation), for to utilize horizontal line array the radiated noise of submarine target to be carried out to the sketch of walkaway, when naval vessel or measured target process horizontal line array, samples to noise signal, completes the detection to noise source.The linear array forming for N primitive, because the existence of towed speed is moved mutually, makes the signal and the radiation sound source that receive have the inconsistent situation of frequency, and sound source motion receive frequency uprises relatively, deviates from sound source motion receive frequency step-down.

For radiated noise signals s (t) complex envelope, can be expressed as

$s\left(t\right)=\mathrm{Re}\left[\stackrel{\&CenterDot;}{s}\left(t\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\right]$

Signal arrives receiving hydrophone through certain time-delay, and N array element stack forms f (t)

$f\left(t\right)=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_n\left(t\right)s(t-\frac{x_n}{c})$

$=\mathrm{Re}\left[\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_n\left(t\right)\stackrel{\&CenterDot;}{s}(t-\mathrm{\&tau;}\left(n\right)){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\right]$

When reception battle array is moved with speed v, each run duration is △ t, and angle is a _n, corresponding path changes in time

△x _n=v△tcosa _n

Receiving signal is

$f\left(t\right)=\mathrm{Re}\left[\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_n\left(t\right)\stackrel{\&CenterDot;}{s}(t-\frac{x_n-{\mathrm{\&Delta;x}}_n}{c}){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\right]$

$=\mathrm{Re}\left[\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_n\left(t\right)\stackrel{\&CenterDot;}{s}(t-\frac{x_n}{c}+\frac{\mathrm{v\&Delta;}t\cos {\mathrm{\&alpha;}}_n}{c}){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\right]$

Motion receives to echo signal to consider to drag linear array, due to sampling time interval sequence variation, can cause receive frequency and echo signal frequency inconsistent.

Step (2) and step (3) will be dragged linear array to move middle reception signal time segment and be processed, to different time sections, drag each array element of linear array basic matrix to receive signal and carry out frequency-domain beamforming processing, and the output frequency division band after frequency-domain beamforming is carried out to energy integral obtain wave beam output.The object that sonar wave beams forms is that the linear array that a plurality of primitives are formed obtains directive property in a predetermined direction through suitable processing, echo signal can utilize line spectrum detection technique useful signal to be detected, further utilize frequency-domain beamforming to be processed, be conventionally directed to target zone f _min～f _maxbroadband signal can be analyzed the signal of frequency range, extract signal in this frequency range, then obtain wave beam output, while receiving due to array motion can there is Doppler shift in target frequency, be that receive frequency and echo signal are inconsistent, so the error that in the time of should specifically considering linear array reception signal, Doppler frequency domain is brought.

Drag linear array for passive synthetic aperture principle schematic as Fig. 2 (see accompanying drawing explanation), be applied to passive synthetic aperture normal signal detection algorithm, the towed array array element distance that array number is N is d, movement velocity is v.At t=0 constantly, N unit basic matrix carries out spatial sampling to sound field, and τ is after second, basic matrix displacement is v τ, selects rational parameter v, makes basic matrix in mobile q primitive position time interval τ second, after motion J τ, expand to (N+Jq) individual array element and can be considered a virtual battle array.For a uniformly-spaced linear array that is spaced apart d being formed by N nautical receiving set, with speed v, drag forward, consider single-point sound source under water, consider Doppler's impact, receiving signal sampling frequency is f _s, sampling time interval is T _s=1/f _s, actual signal sampling time interval is t _i, the time samples of each nautical receiving set can be expressed as:

x _n(t _i)=Aexp[j2πf(t _i-τ _n)]+ξ _n,j

N=1 in formula, 2 ... N, array element; A-amplitude; F-frequency; t _i-i sampling time, τ _nbe n nautical receiving set with respect to No. 1 nautical receiving set time delay, as shown in Figure 1,

τ _n=(R _n-R ₁)/c

ξ wherein _n,jindependent, zero-mean gaussian random noise.

To drag linear array to move middle reception signal time segment and process, single nautical receiving set seasonal effect in time series Fourier transform is

$X_n\left(f\right)=\underset{i=1}{\overset{J}{\mathrm{\&Sigma;}}}{x}_n\left(t_i\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{\mathrm{ft}}_i)$

To different time sections, drag each array element of linear array basic matrix to receive signal and carry out frequency-domain beamforming processing, at moment t ₀wave beam be output as:

$b{(f_0,{\mathrm{\&theta;}}_s)}_{t_0}=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_n\left(f_0\right)\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0\frac{d(n-1)\sin {\mathrm{\&theta;}}_s}{c}\right]$

θ in formula _sthe angle changing.At t=t _iconstantly, battle array response is+τ:

$b{(f_0,{\mathrm{\&theta;}}_s)}_t=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}\left\{\underset{i=2}{\overset{J}{\mathrm{\&Sigma;}}}{x}_n(t_i+\mathrm{\&tau;})\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0{t}_i)\right\}\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0\frac{d(n-1)\sin {\mathrm{\&theta;}}_s}{c}\right]$

Can draw:

$b{(f_0,{\mathrm{\&theta;}}_s)}_t=b{(f_0,{\mathrm{\&theta;}}_s)}_{t_0}\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0(\mathrm{\&tau;}-\frac{\mathrm{v\&tau;}\sin \mathrm{\&theta;}}{c})\right]$

J τ is after second, and array move distance is vJ τ, therefore at moment t _i+ l τ expression formula is:

$B{(f_0,{\mathrm{\&theta;}}_s)}_{\mathrm{J\&tau;}}=\underset{i=1}{\overset{J}{\mathrm{\&Sigma;}}}b{(f_0,{\mathrm{\&theta;}}_s)}_{\mathrm{i\&tau;}}\exp [-j{\mathrm{\&Phi;}}_i]$

In formula: i-beamlet produces the output of synthetic aperture wave beam after J phase compensation relevant summation, i=1 ..., J, Φ _i-phase correction term, ${\mathrm{\&Phi;}}_i=2\mathrm{\&pi;}{f}_0(1\&PlusMinus;\frac{v\sin {\mathrm{\&theta;}}_s}{c})\mathrm{i\&tau;}.$

Motion drags overlapping array element number in linear array passive synthetic aperture method directly to determine the estimated result of phase correction term, when conventional passive synthetic aperture algorithm requires array in succession to move for twice, the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, array element should completely overlappingly be usingd accurate as receiving the phase correction term of signal on rear underlapped nautical receiving set, and optimum superposing array element number is N/2.Actual basic matrix owing to being subject to the impact of the disturbance in underwater complex surrounding medium and path, can not make array in succession before and after twice motion, accurately reach coincidence when motion.The non-overlapped aperture of a kind of motion proposing drags linear array passive synthetic aperture signal detecting method can be directly used in phase delay compensation, need not consider that array element is mutually completely overlapping, at Beam Domain, replaces its enterprising line phase correction in array element territory.

T=0 constantly n array element receives signal x _n(t _i), it is made to M point FFT, corresponding k array element is X ₀(k, K), K=1 ..., M, further does after frequency-domain beamforming each array element output cumulative, and each array element output is done cumulative it to be converted to Beam Domain by array element territory:

$S_0=\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_0(k,K)\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}(k-1)\mathrm{\&Delta;\&tau;}]$

F in formula _s-sample frequency, equally the signal x after second by motion τ _n(t _i+ τ), it is made to M point FFT, corresponding k array element is X ₁(k, K), K=1 ..., M, after frequency-domain beamforming is further made in integrating step (2), (3), each array element output adds up, and has:

${\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1=\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_1(k,K)\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}(k-1)\mathrm{\&Delta;\&tau;}]$

Step in technical scheme (4) moves forward into line phase to time delay and locus respectively to be estimated, for keeping phase place consistent, respectively locus is moved and time delay variation is paid attention to, to motion τ S after second ₁compensate, space motion compensation, move distance is v τ, can be for each array element distance d at this v τ non-integral multiple,

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">P</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}\frac{\mathrm{v\&tau;}}{d}\mathrm{\&Delta;\&tau;}]$

Consider time delay equalization, move τ second, have:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2={\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}\mathrm{\&tau;}]$

Combine and consider space and upper variation of time, i.e. time delay and locus travel(l)ing phase correction, by P ₁and P ₂be added, obtain array and move the total phase place correction-compensation in front and back:

P ₀=P ₁+P ₂

Described scheme step (5) considers each phase correction term of time segment to compensate for wave beam output, and coherent combination output obtains the corresponding orientation of object beam, realizes the effective detection to echo signal.Total phase place correction-compensation is cumulative, and to obtain corresponding synthetic output relevant with angle, and Virtual array length is v τ, and after expansion, array element total length is Nd+v τ, with this, is moving J τ after second, and N array element basic matrix expands to the linear array that length is Nd+vJ τ.The cumulative output of coherent combination is the non-overlapped aperture of motion and drags linear array passive synthetic aperture detection method thus, because passive synthetic aperture algorithm need not consider that array element is mutually completely overlapping before and after mobile, can directly carry out phase place correction-compensation, thereby realize the effective detection to echo signal.

In technique scheme, the non-overlapped aperture that is used for moving is dragged linear array passive synthetic aperture input and differentiates method flow diagram and (see accompanying drawing explanation) as shown in Figure 3, successively signal is analyzed and built to ship-radiated noise characteristic and receive model dragging linear array to move lower motion Doppler, and on this Signal reception model basis, will drag linear array to move a middle reception array element reception signal time segment and process, to different time sections, drag each array element of linear array basic matrix to receive signal and carry out frequency-domain beamforming processing, consider the factor impacts such as Doppler shift, for the output frequency division band after frequency-domain beamforming, carry out energy integral and further obtain wave beam output, in conjunction with the signal movement building, receive tectonic model, respectively time delay and locus are moved forward into line phase estimation, last just each phase correction term of time segment is for the phase compensation correction of wave beam output, the cumulative output of coherent combination obtain the corresponding orientation of object beam, thereby realize the effective detection to echo signal.

In such scheme, comprise the analysis of the target radiated noise such as naval vessel under water and drag linear array to move the structure that lower motion Doppler receives signal model, wherein analyze ship noise characteristic not only for the passive synthetic aperture technology of underwater propeller cutting formation line spectrum signal lays the foundation, the Doppler that linear array array moves receives signal model structure signal formation, array element mobile reception etc. is made to clear understanding, and the integrated array of clearer and more definite passive synthetic aperture receives signal formation and phase place correction-compensation method.The error that while receiving signal for linear array, Doppler frequency domain is brought, considers the phase place that the factors of influence such as time delay, locus move, Doppler shift bring inconsistent.

As shown in Figure 1, this figure is that the present invention utilizes horizontal line array the radiated noise of submarine target to be carried out to the sketch of walkaway, when naval vessel under water or measured target are during through horizontal line array, towing line array is sampled to noise signal, the motion of nautical receiving set array element finishes receiving the detection to noise source, each nautical receiving set numbering is respectively nautical receiving set No. 1, No. 2 nautical receiving sets, (N-1) number nautical receiving set, N nautical receiving set, while not moving, each nautical receiving set receives between signal has the regular hour to postpone, receive signal form identical, phase place is different, consider underwater ambient noise, analyze the target radiated noise characteristic such as naval vessel under water, build linear array and receive signal model in resting state.

The present invention proposes the non-overlapped aperture of a kind of motion and drags linear array passive synthetic aperture target echo detection and resolution method, in considering the complicated Underwater Acoustic Environment of the actual underwater sound, drag the in the situation that linear array motion is irregular causing array element aperture not exclusively overlapping, application passive synthetic aperture technology realizes weak echo signal under water is effectively detected, building on the basis of linear array resting state reception signal model, carrying out as follows subsequent treatment:

Step (1) is configured in drags linear array to move the lower motion Doppler to echo signal to receive model;

When step (2) utilizes according to passive synthetic aperture sonar algorithm twice motion in succession that array determines in the time interval, the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period, and each array element reception signal of different time sections is carried out to frequency-domain beamforming processing;

Step (3) is carried out energy integral to the output frequency division band after frequency-domain beamforming and is obtained each time period wave beam output;

Step (4) receives model by the Doppler who drags linear array to move lower structure, respectively time delay and locus is moved forward into line phase estimation;

Step (5) is by each phase correction term of time segment for wave beam output compensation, and the cumulative output of coherent combination obtains the corresponding orientation of object beam by its time bearing history figure.

Step in such scheme (1) considers that linear array exists motion Doppler shift while receiving signal, when wherein array element moves, build linear array passive synthetic aperture algorithm and receive signal as shown in Figure 2 by each time of reception section, t=0 constantly, N unit basic matrix carries out spatial sampling to sound field, τ is after second, mobile q primitive position (aperture can be not exclusively overlapping), after motion J τ, expands to (N+Jq) individual array element and can be considered a virtual battle array.Step (2), (3) error that while considering linear array reception signal, Doppler frequency domain is brought, when linear array motion receives signal because move time delay and locus if guarantee the adjacent time interval move before and after twice array have over half aperture length of array length and overlap and can do correction-compensation to it, combine and consider space and upper variation of time, be time delay and locus travel(l)ing phase correction, time delay and locus travel(l)ing phase correction-compensation are added, obtain array and move the total phase place correction-compensation in front and back, then each phase correction term of time segment compensated for wave beam output, coherent accumulation array output obtains the corresponding orientation of object beam, the effective detection of realization to echo signal.

As shown in Figure 3, this figure is that the non-overlapped aperture of motion is dragged linear array passive synthetic aperture input and differentiated method flow diagram, in conjunction with to dragging the irregular not exclusively overlapping situation passive synthetic aperture in array element aperture that causes of linear array motion for signal detecting method in the complicated Underwater Acoustic Environment of the actual underwater sound of the analysis integrated considerations of target radiated noise such as naval vessel under water, to dragging linear array to move lower motion Doppler, receive model construction, divide frequency band, the output of time segment wave beam, time delay and the estimation of locus travel(l)ing phase, phase place correction-compensation is done concrete elaboration for the synthesis of steps such as outputs.

In a word, core of the present invention is: first, utilize ship-radiated noise specificity analysis, complete dragging linear array to move the lower structure that the motion Doppler of signal is received to model; Secondly, in the situation that considering Doppler shift, time segment is carried out frequency-domain beamforming processing to each array element reception signal, and frequency division band carries out energy integral and obtains each time period wave beam output; Then, utilizing linear array signal to receive motion Doppler model considers in the not exclusively overlapping situation in array element aperture, due to time delay and locus move if guarantee the adjacent time interval move before and after twice array have over half aperture length of array length and overlap and can do correction-compensation to it, further illustrate and needn't overlap completely by refinement requirement array aperture, meet underwater complex Underwater Acoustic Environment situation to the impact of dragging linear array to move along a straight line and produce, realistic service condition; Finally, in passive synthetic aperture signal detecting method based on the non-overlapped aperture of motion, consider Doppler frequency deviation and ship noise radiation characteristic under water, be beneficial to the reasonable use of the methods such as motor message detection and towboat noise cancellation, there is certain engineering practicability.

Embodiment

As shown in Figure 1, when naval vessel or measured target are through horizontal line array under water, each array element is sampled to noise signal, because the existence of towed speed is moved mutually, makes the signal and the radiation sound source that receive have the inconsistent situation of frequency.In conjunction with Fig. 2 linear array basic matrix, do rectilinear motion, individual for N is equidistantly the isotropy linear array of d, and speed is v, and the t=0 of take constantly the 1st array element receives ships radiated noise signal as normative reference, the 2nd array element is △ τ with respect to the 1st array element propagation delay, and n array element receives signal and is

x _n(t _i)=Aexp[j2πf(t _i-τ _n)]+ξ _n(t _i)

A-amplitude in formula; F-frequency; t _i-i sampling time, τ _nbe that n nautical receiving set array element is with respect to the 1st array element propagation delay

τ _n=(R _n-R ₁)/c

ξ _n(t _i) represent independent zero-mean ambient sea noise.

With speed v motion τ, after second, n array element receives signal and is

x _n(t _i+τ)=Aexp[j2πf(t _i+τ-τ _n(t _i+τ))]+ξ _n(t _i+τ)

Consider t=0 constantly, will drag linear array to move middle reception signal time segment and process, for each nautical receiving set seasonal effect in time series Fourier transform, be

$X_n\left(f\right)=\underset{i=1}{\overset{J}{\mathrm{\&Sigma;}}}{x}_n\left(t_i\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{\mathrm{ft}}_i)$

To different time sections, drag each array element of linear array basic matrix to receive signal and carry out frequency-domain beamforming processing, at moment t ₀wave beam be output as:

$b{(f_0,{\mathrm{\&theta;}}_s)}_{t_0}=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_n\left(f_0\right)\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0\frac{d(n-1)\sin {\mathrm{\&theta;}}_s}{c}\right]$

θ in formula _sthe angle changing.At t=t _iconstantly, battle array response is+τ:

$b{(f_0,{\mathrm{\&theta;}}_s)}_t=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}\left\{\underset{i=2}{\overset{J}{\mathrm{\&Sigma;}}}{x}_n(t_i+\mathrm{\&tau;})\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0{t}_i)\right\}\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0\frac{d(n-1)\sin {\mathrm{\&theta;}}_s}{c}\right]$

When towboat continues, by speed v motion, can continuously spatial information to be synthesized to Virtual array, at phase correction term, estimate that when accurate, the virtual synthetic aperture obtaining can be equivalent to the physical pore size that actual array element forms.Consider actual basic matrix in when motion owing to being subject to the impact of the disturbance in underwater complex surrounding medium and path, array can not accurately reach coincidence before and after twice motion in succession.In the situation that need not considering that array element is mutually completely overlapping, at Beam Domain, replace its enterprising line phase correction in array element territory.T=0 constantly n array element receives signal x _n(t _i), it is made to M point FFT, corresponding k array element is X ₀(k, K), by different time sections drag each array element of linear array basic matrix receive signal carry out frequency-domain beamforming process after each array element output cumulative, each array element output is done cumulative it to be converted to Beam Domain by array element territory:

$S_0=\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_0(k,K)\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}(k-1)\mathrm{\&Delta;\&tau;}]$

F _s-sample frequency, equally the signal x after second by motion τ _n(t _i+ τ), it is made to M point FFT, corresponding k array element is X ₁(k, K), K=1 ..., M, after equally different time sections being dragged each array element of linear array basic matrix to receive signal to make frequency-domain beamforming, each array element output is cumulative:

${\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1=\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}{X}_1(k,K)\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}(k-1)\mathrm{\&Delta;\&tau;}]$

Respectively time delay and locus are moved forward into line phase and estimate, keeping on the basis that phase place is consistent, respectively locus is moved and time delay variation is paid attention to, to motion τ S after second ₁compensate, space motion compensation, move distance is v τ, can be for each array element distance d at this v τ non-integral multiple,

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">P</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}\frac{\mathrm{v\&tau;}}{d}\mathrm{\&Delta;\&tau;}]$

Time delay equalization, moves τ second, has:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2={\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">S</figure-callout>}}_1\&CenterDot;\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA00001839333400012.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(K-1)\frac{\mathrm{fs}}{M}\mathrm{\&tau;}]$

Combine and consider space and upper variation of time, i.e. time delay and locus travel(l)ing phase correction, by P ₁and P ₂be added, obtain array and move the total phase place correction-compensation in front and back:

P ₀=P ₁+P ₂

Each phase correction term compensated for wave beam output, associating time, space phase correction-compensation, the cumulative output of coherent combination obtains the corresponding orientation of object beam, total phase place correction-compensation is cumulative, and to obtain corresponding synthetic output relevant with angle, Virtual array length is v τ, after expansion, array element total length is Nd+v τ, with this, is moving J τ after second, and N array element basic matrix expands to the linear array that length is Nd+vJ τ.The cumulative output of coherent combination is the non-overlapped aperture of motion and drags linear array passive synthetic aperture detection method thus, because passive synthetic aperture algorithm need not consider that array element is mutually completely overlapping before and after mobile, can directly carry out phase place correction-compensation, thereby realize the effective detection to echo signal.

In a word, the invention discloses a kind of detection and resolution method of dragging linear array passive synthetic aperture echo signal based on the non-overlapped aperture of motion, utilize the target radiated noise specificity analysis such as naval vessel under water, complete dragging linear array to move the lower structure that the motion Doppler of signal is received to model, avoid because complicated Underwater Acoustic Environment impact makes tow line array be difficult to maintain constant speed, then in the time of can not guaranteeing continuous coverage, the locus of overlapping nautical receiving set is identical, the non-overlapped aperture adjacent time interval of passive synthetic aperture algorithm proposing moves front and back array element for twice and need not overlap completely, utilizing respectively time delay and locus to move equiphase modifying factor can fine compensation motion phase error.Due to time delay and locus move if guarantee the adjacent time interval move before and after twice array have over half aperture length of array length and overlap and can do correction-compensation to it, meet underwater complex Underwater Acoustic Environment situation to the impact of dragging linear array to move along a straight line and produce, the testing conditions of the echo signals such as realistic naval vessel under water, is beneficial to echo signal a little less than calm type under water is effectively detected and differentiated.

Other guide in specification documents, for the those of ordinary skill in this professional domain, all can carry out technology realization, repeats no more here.It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although the present invention is had been described in detail with reference to embodiment, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is modified or is equal to replacement, do not depart from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of claim scope of the present invention.

Claims (10)

1. passive synthetic aperture target echo detection and a resolution method, the method application passive synthetic aperture technology realizes weak echo signal under water is effectively detected, and described method comprises:

Step 101) be configured in and drag linear array to move the lower motion Doppler to echo signal to receive model;

When step 102) dragging linear array array twice motion in succession occur at interval at a fixed time according to the utilization of passive synthetic aperture sonar algorithm, it is average that the echo signal respectively nautical receiving set of lap on locus being received is done simple crosscorrelation, the echo signal that is about to receive is carried out time segment processing, analyze the reception signal of every adjacent twice time period, the echo signal then each array element of different time sections being received is carried out frequency-domain beamforming processing;

Step 103) the output frequency division band after frequency-domain beamforming is carried out to energy integral and obtain each time period wave beam output;

Step 104) by the Doppler who drags linear array to move lower structure, receive model, respectively time delay and locus are moved forward into line phase estimation, and obtain phase correction term according to the phase estimation obtaining;

Step 105) by each phase correction term of time segment for compensation process 103) wave beam output, cumulative and then acquisition course figure time aziniuth to the wave beam output coherent combination after compensation, read orientation, target place, its azimuth recording is processed and differentiated, realize the detection to target.

2. passive synthetic aperture target echo detection according to claim 1 and resolution method, it is characterized in that, the concrete overlapping number of the nautical receiving set of described lap is to drag half of the total number of linear array array element, and the locus of nautical receiving set is completely overlapping can effectively avoid cannot guaranteeing continuous coverage owing to dragging linear array to be difficult to maintain constant speed time.

3. passive synthetic aperture target echo detection according to claim 1 and resolution method, is characterized in that, described phase correction term be that time delay is estimated and locus travel(l)ing phase is estimated with.

4. passive synthetic aperture target echo detection according to claim 1 and resolution method, is characterized in that, described step 102) further comprise following sub-step:

When step 102-1) dragging linear array array twice motion in succession occur at interval at a fixed time according to the utilization of passive synthetic aperture sonar algorithm, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period;

Wherein, this step also comprises the useful signal in the echo signal that adopts line spectrum to detect strategy detection reception;

Step 102-2) then each array element of different time sections is received to signal and carry out frequency-domain beamforming processing.

5. passive synthetic aperture target echo detection according to claim 1 and resolution method, is characterized in that, described step 105) further comprise following sub-step:

Step 105-1) according to step 104) " phase estimation is obtained phase correction term " and the step 103 that obtain) in " each time period wave beam output ", time segment is processed, the phase correction term of each time period and the wave beam output of corresponding time period are multiplied each other and waited processing, complete " each phase correction term of time segment is for compensation process 103) wave beam export ";

Step 105-2) signal of above-mentioned each time period is superposeed, the wave beam output after compensation is carried out to coherent combination and add up and then obtain course figure time aziniuth;

Step 105-3) again course figure wave beam output time aziniuth is detected, obtain the corresponding orientation of object beam, be specially: the detection orientation that different frequency bands internal object wave beam is corresponding is carried out to record, quadratic fit is carried out in the orientation of storing in each frequency band, according to result of calculation computer azimuth estimation variance, the detection variance thresholding of the orientation estimation variance of calculating and setting is compared, if be less than thresholding, the underwater acoustic target signal result detecting is true, receive Underwater Target Signal and really contain underwater acoustic target signal, otherwise testing result is false-alarm, in the signal receiving, do not contain echo signal, detection and the location of echo signal have been combined.

6. drag linear array move passive synthetic aperture target echo detection and the resolution system in non-overlapped aperture, this system applies passive synthetic aperture technology realizes weak echo signal under water is effectively detected, and described system comprises:

Acceptance Model is set up module, for being configured in, drags linear array to move the lower motion Doppler to echo signal to receive model;

The first processing module, when dragging linear array array according to the utilization of passive synthetic aperture sonar algorithm twice motion in succession occur at interval at a fixed time, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period, then each array element of different time sections is received to signal and carry out frequency-domain beamforming processing;

The second processing module, carries out energy integral for the output frequency division band to after frequency-domain beamforming and obtains each time period wave beam output;

Space-time phase correction term acquisition module, receives model for the Doppler by dragging linear array to move lower structure, respectively time delay and locus is moved forward into line phase estimation, and obtains phase correction term according to the phase estimation obtaining; With

Motion phase error compensation and testing result output module, for each phase correction term of time segment exported for compensating described wave beam, wave beam output after compensation is carried out to coherent combination to add up and then obtains course figure time aziniuth, by its time bearing history figure, obtain the corresponding orientation of object beam, the detection and the location that complete echo signal again.

7. passive synthetic aperture target echo detection according to claim 6 and resolution system, is characterized in that, the concrete overlapping number of the nautical receiving set of described lap is to drag half of the total number of linear array array element.

8. passive synthetic aperture target echo detection according to claim 6 and resolution method, is characterized in that, described phase correction term be that time delay is estimated and locus travel(l)ing phase is estimated with.

9. passive synthetic aperture target echo detection according to claim 6 and resolution system, is characterized in that, described the first processing module further comprises following submodule:

Time segment is processed submodule, when dragging linear array array according to the utilization of passive synthetic aperture sonar algorithm twice motion in succession occur at interval at a fixed time, respectively the nautical receiving set reception signal of lap on locus is done to simple crosscorrelation average, be about to receive signal and carry out time segment processing, analyze the reception signal of every adjacent twice time period; With

Frequency-domain beamforming submodule, carries out frequency-domain beamforming processing for each array element of different time sections is received to signal.

10. passive synthetic aperture target echo detection according to claim 1 and resolution method, is characterized in that, described motion phase error compensation and testing result output module further comprise following submodule:

Motion phase error compensation submodule, for exporting each phase correction term compensation wave beam of time segment;

Coherent combination is processed submodule, carries out coherent combination add up for the wave beam output to after compensation; With

Testing result output sub-module, for by time aziniuth course figure obtain the corresponding orientation of object beam, the detection and the location that complete echo signal.

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