CN103969624A - Beam domain coherent azimuth estimation method and system based on fluctuated phase alignment - Google Patents

Abstract

The invention relates to a beam domain coherent azimuth estimation method based on fluctuated phase alignment. The method is implemented on the basis of a long-line sonar array formed by M equidistant hydrophones. The method includes the first step of conducting frequency point accumulative division on broadband array element domain signals received by the sonar array to obtain array element domain signals of single frequency points, the second step of obtaining direction guidance vectors of incoming wave signals of the sonar array, the third step of converting the array element domain signals of the single frequency points into a beam domain according to the obtained direction guidance vectors, the fourth step of conducting fluctuation coherent processing on the beam domain signals, and the fifth step of calculating a beam output energy power value of the beam domain signals subjected to fluctuation coherent processing and then realizing estimation of target azimuth. The beam domain coherent azimuth estimation method based on fluctuated phase alignment effectively improves the suppression effect of output gain and strong interference of the signals and has excellent spatial resolving capability.

Description

The relevant direction estimation method of a kind of Beam Domain based on fluctuating phase alignment and system

Technical field

The present invention relates to field of underwater acoustic signal processing, particularly the relevant direction estimation method of a kind of Beam Domain based on fluctuating phase alignment and system.

Background technology

The orientation of how to confirm information source is a basic problem of Array Signal Processing, and this is also one of vital task of many applications such as radar, sonar.All need multiple targets to position in various fields such as ocean development, precise guidance, biomedicine, geologic prospecting, national defence and civilian construction.Along with scientific and technical fast development, the requirement of the indexs such as target resolution characteristic and Parameter Estimation Precision is also improved day by day, therefore array high resolution target location technology is very important research contents always.Many Underwater Target Detection systems, automatic guidance system and communication system all need array high resolution target location technology to improve its technical feature.

But due to the waveguiding effect of acoustic propagation and multipath effect based on propagation medium, in fact not only inhomogeneous in space distribution but also become while being random.Therefore, acoustical signal also will be random fluctuation in transmitting procedure.This fluctuating can cause receive signal time become, space-variant, and present selectivity decline.The fluctuation effect of bringing for this transmission channel is estimated the impact bringing to echo signal incoming wave orientation, current traditional detection method is seldom mentioned.

Summary of the invention

The object of the invention is to overcome the fluctuation effect that existing detection method do not consider that transmission channel brings and estimate the defect impacting to echo signal incoming wave orientation, thereby the relevant direction estimation method of a kind of Beam Domain based on fluctuating phase alignment and system are provided.

To achieve these goals, the invention provides the relevant orientation of a kind of Beam Domain based on the fluctuating phase alignment estimation technique, the long line sonar array that the method forms based on M equally spaced nautical receiving set; The method comprises:

Step 1), array element territory, broadband signal that described sonar array is received does frequency accumulation and divides, and obtains the array element territory signal of single frequency;

Step 2), ask for the direction guiding vector of described sonar array incoming wave signal;

Step 3), according to step 2) the direction guiding vector of trying to achieve, by step 1) the array element territory signal of the single frequency that obtains is transformed into Beam Domain;

Step 4), to step 3) the Beam Domain signal that obtains does fluctuating relevant treatment;

Step 5), in step 4) in through the Beam Domain calculated signals wave beam output energy work rate value of fluctuating relevant treatment, thereby the estimation in realize target orientation.

In technique scheme, described step 2) comprising:

Step 2-1), for single frequency, invisible scanning phase angle theta, obtains the beamformer output signal of sonar array,

Wherein, n _m(f ₀, t) be the additive noise on array element m, τ _m(θ) be incoming wave signal r _m(f ₀, the t) relative time delay of arrival array element m;

Step 2-2), definition beam scanning guiding phase angle range Theta ₁, θ ₁..., θ _d, by invisible scanning phase angle theta _iexpand to whole steering vectors, thereby obtain the direction guiding vector of described sonar array incoming wave signal, this direction guiding vector expression is as follows:

${\widehat{\mathrm{\α}}}_m(f_0,\mathrm{\θ})=\left[\begin{array}{cccc}1& 1& ...& 1\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)}\\ ...& ...& ...& ...\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)(M-1)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)(M-1)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)(M-1)}\end{array}\right].$

In technique scheme, described step 3) comprising:

Step 3-1), array received orientation model while setting single broadband signal incident, its expression formula is as follows:

$y_{\mathrm{BF}}\left(t\right)=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{\inf }\left(t\right)$

$=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}[{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{f_i}\left(t\right)]$

Wherein, for array to incoming wave signal to specifying frequency f _idirection guiding vector, that centre frequency is f _inarrow band signal, K be split after narrow band signal quantity;

Step 3-2), array beams output signal is transformed to frequency domain form, can obtain the array frequency domain wave beam response of single frequency, invisible scanning phase angle, its expression formula is:

$\hat{Y}=(f_0,{\mathrm{\θ}}_i)=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{e}^{-j2\mathrm{\π}{f}_0{\mathrm{\τ}}_m\left({\mathrm{\θ}}_i\right)}{R}_m\left(f_0\right)+N_m\left(f_0\right)$

$=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_0,{\mathrm{\θ}}_i)R_m\left(f_0\right)+N_m\left(f_0\right)i=\mathrm{1,2},...,D;$

Wherein,

R _m(f ₀)＝[R ₁(f ₀),R ₂(f ₀),…,R _M(f ₀)] ^T；

N _m(f ₀)＝[N ₁(f ₀),N ₂(f ₀),…,N _M(f ₀)] ^T；

Step 3-3), solve the Beam Domain output signal vector of single frequency, thereby the array element territory signal of realizing single frequency is transformed into Beam Domain, its expression formula is:

$\hat{Y}(f_j,\widetilde{\mathrm{\θ}})=\{\hat{Y}(f_j,{\mathrm{\θ}}_1),\hat{Y}(f_j,{\mathrm{\θ}}_2),...,\hat{Y}(f_j,{\mathrm{\θ}}_D)\}j=\mathrm{1,2},...,K.$

In technique scheme, described step 4) comprising:

Step 4-1), ask for the Beam Domain output signal of single frequency at the instantaneous amplitude envelope A of a certain sampling instant _beam(f ₀, t _i) and instantaneous wave beam drift phase place

Step 4-2), according to step 4-1) result of calculation the expression formula of single frequency Beam Domain output signal is rewritten as to polar coordinate representation form;

${\hat{Y}}_{\mathrm{BF}}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)}$

$=A_{\mathrm{Beam}}(f_0,t_i)\cos \widetilde{\mathrm{\Θ}}(f_0,t_i)+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \widetilde{\mathrm{\Θ}}(f_0,t_i)$

Step 4-3), in plural polar coordinates plane, the difference alignment disposal route of application signal fluctuation phase place, carries out alignment compensation by the instantaneous fluctuating difference of Beam Domain output signal vector, obtains the Beam Domain alignment compensation factor;

${\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)={\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)-2{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-1})+{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-2})$

Step 4-4), by step 4-3) the Beam Domain alignment compensation factor that obtains replaces the instantaneous wave beam drift phase place in the Beam Domain output signal of single frequency, obtains the beam signal through fluctuating relevant treatment;

${\hat{Y}}_{\mathrm{BF}}^{\′}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]$

$=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)}.$

In technique scheme, in described step 5) in, the computing formula of energy work rate value is:

$\mathrm{PFA}\_\mathrm{BF}\left\{Y_{\mathrm{BF}}^{\′}(f,t)\right\}={\mathrm{\Σ}}_j^K{\left\{\mathrm{Re}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2+{\mathrm{\Σ}}_j^K{\left\{\mathrm{Im}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2$

Wherein:

$\mathrm{Re}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}$

$\mathrm{Im}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}.$

The present invention also provides the relevant orientation of a kind of Beam Domain based on fluctuating phase alignment estimating system, the long line sonar array that this system forms based on M equally spaced nautical receiving set; This system comprises: module is divided in frequency accumulation, direction guiding vector is asked for module, signal conversion module, fluctuating related process module, energy work rate value computing module; Wherein,

Described frequency accumulation is divided module and is done frequency accumulation division for array element territory, the broadband signal that described sonar array is received, and obtains the array element territory signal of single frequency;

Described direction guiding vector is asked for module for asking for the direction guiding vector of described sonar array incoming wave signal;

Described signal conversion module asks for according to described direction guiding vector the direction guiding vector that module is tried to achieve, and the array element territory signal of the single frequency that described frequency accumulation division module is obtained is transformed into Beam Domain;

The Beam Domain signal that described fluctuating related process module obtains described signal conversion module does fluctuating relevant treatment;

Described energy work rate value computing module is to the Beam Domain calculated signals wave beam output energy work rate value through fluctuating relevant treatment in described fluctuating related process module, thus the estimation in realize target orientation

The invention has the advantages that:

1, the present invention is by introducing airspace filter thought, utilize the different spaces of the each primitive of sensor array to distribute, in conjunction with the spatial coherence difference of array element territory echo signal and noise, effectively improve output gain and the strongly disturbing inhibiting effect of signal, the broadband signal that array element territory is received transforms to the orientation output form of Beam Domain, obtains better spatial resolving power.

2, the present invention is by completing the drift phase alignment difference processing of focus beam domain output signal under uncertain fluctuating channel, effectively utilize the phase shift homogeneity difference of beam signal and ground unrest, on array filter gain basis, spatial domain, combine again phase coherence gain, obviously improve the accuracy that target incoming wave orientation is estimated, improved the estimated capacity of differentiating different target ripple and reach orientation.

Brief description of the drawings

Fig. 1 is the process flow diagram of the inventive method;

Fig. 2 be the inventive method based on the schematic diagram of sonar array;

Fig. 3 is frequency domain--the wave beam orientation Output rusults figure that adopts energy measuring target Bearing Estimation method of the prior art to obtain;

Fig. 4 is frequency domain--the wave beam orientation Output rusults figure that the application Beam Domain alignment of the present invention Coherent Targets orientation estimation technique obtains;

Fig. 5 be Beam Domain output signal in 60 degree directions, the schematic diagram of the beam signal phase alignment compensation result at frequency 500Hz place;

Fig. 6 is in the frequency shown in accompanying drawing 3,4--wave beam position and orientation matrix output basis is upper, and the broadband signal of choosing frequency range 300 ~ 500Hz scope adds up relevant treatment, the schematic diagram of the 60 degree arrival bearings' that obtain wave beam output performance result.

Embodiment

Now the invention will be further described by reference to the accompanying drawings.

Before method of the present invention is elaborated, first to the inventive method based on sonar array do brief description.

As shown in Figure 2, the inventive method based on sonar array comprise M nautical receiving set (being also referred to as the primitive of sonar array), these nautical receiving sets are arranged in a long linear array jointly, and the distance between each nautical receiving set equates, represent the distance between nautical receiving set with d.

With reference to figure 1, method of the present invention comprises the following steps:

Step 1), received array element territory, broadband signal done to frequency accumulation divide, obtain the array element territory signal of single frequency.

The waterborne target radiated noise signals that sonar array receives has broader frequency spectrum characteristic, and it can be seen as some side frequency narrow band signal sums.Therefore, can set received broadband signal s (t) and be formed by stacking by K narrow band signal,

$s\left(t\right)=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{s}_{f_i}\left(t\right)$

Wherein that centre frequency is f _inarrow band signal.

Sonar array, except receiving waterborne target radiated noise signals, also can receive undesired signal.The broadband interference n receiving _inf(t) also can be written as K arrowband interference noise sum,

$n_{\inf }\left(t\right)=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{n}_{f_i}\left(t\right)$

Step 2), ask for the direction guiding vector of sonar array incoming wave signal.

The moment that arrives each array element in sonar array due to signal is variant, and homogeneous plane wave has different time delay in the response of each array element output terminal.Therefore the receiving array being made up of M non-directional array element, the far-field signal obtaining in each array element can be expressed as r ₁(t), r ₂(t) ..., r _m(t), for single frequency, invisible scanning phase angle theta, the beamformer output signal of sonar array is expressed as:

$y_{\mathrm{BF}}(t,\mathrm{\θ})=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}[e^{-j2\mathrm{\π}{f}_0{\mathrm{\τ}}_m\left(\mathrm{\θ}\right)}{r}_m(f_0,t)+n_m(f_0,t)]$

In formula, n _m(f ₀, t) be the additive noise on array element m, τ _m(θ) be incoming wave signal r _m(f ₀, the t) relative time delay of arrival array element m.Known sonar array is uniform line array, and array element is spaced apart d, taking the left side the first array element as reference point, as shown in Figure 2, has

τ _m(θ)＝(d/c)sin(θ)(m-1)

Definition beam scanning guiding phase angle range Theta ₁, θ ₂..., θ _d, by invisible scanning phase angle theta _iexpand to whole steering vectors, can obtain:

${\widehat{\mathrm{\α}}}_m(f_0,\mathrm{\θ})=\left[\begin{array}{cccc}1& 1& ...& 1\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)}\\ ...& ...& ...& ...\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)(M-1)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)(M-1)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)(M-1)}\end{array}\right]$

Try to achieve y _bFin (t, θ) expression formula phase angular region extend type, the direction guiding vector of the array that namely will ask for to incoming wave signal.

Step 3), according to step 2) the direction guiding vector of trying to achieve, by step 1) the array element territory signal that obtains is transformed into Beam Domain.

According to step 1) in result after broadband signal deconsolidation process, the array received orientation model can set single broadband signal incident time is as follows:

$y_{\mathrm{BF}}\left(t\right)=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{\inf }\left(t\right)$

$=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}[{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{f_i}\left(t\right)]$

Wherein, for array (is specified frequency f to incoming wave signal _i) direction guiding vector, it asks for mode in step 2) in be described in detail.K is the narrow band signal quantity of deconsolidation process..

According to step 1) in description, broadband signal can be split into the narrow band signal of single frequency.Describe as an example of the single frequency signal after splitting example.Array beams output signal is transformed to frequency domain form, and the array frequency domain wave beam response that can obtain single frequency, invisible scanning phase angle is:

$\hat{Y}(f_0,{\mathrm{\θ}}_i)=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{e}^{-j2\mathrm{\π}{f}_0{\mathrm{\τ}}_m\left({\mathrm{\θ}}_i\right)}{R}_m\left(f_0\right)+N_m\left(f_0\right)$

$=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_0,{\mathrm{\θ}}_i)R_m\left(f_0\right)+N_m\left(f_0\right)i=\mathrm{1,2},...,D$

Due to:

R _m(f ₀)＝[R ₁(f ₀),R ₂(f ₀),…,R _M(f ₀)] ^T

N _m(f ₀)＝[N ₁(f ₀),N ₂(f ₀),…,N _M(f ₀)] ^T

Combine above-mentioned formula, the Beam Domain output signal vector of single frequency is

$\hat{Y}(f_j,\widetilde{\mathrm{\θ}})=\{\hat{Y}(f_j,{\mathrm{\θ}}_1),\hat{Y}(f_j,{\mathrm{\θ}}_2),...,\hat{Y}(f_j,{\mathrm{\θ}}_D)\}j=\mathrm{1,2},...K$

Above formula represents former M dimension array element territory signal map to transform to D dimension Beam Domain signal, has completed receiving the reconstruct of array data s (f, t) from array element territory to Beam Domain.

Step 4), to step 3) the Beam Domain signal that obtains does fluctuating relevant treatment.

In step 3) in obtain, after the Beam Domain output signal vector of single frequency, according to software radio thought, can obtaining certain sampling instant t _i, single-frequency point Beam Domain complex signal vector instantaneous amplitude envelope be:

$A_{\mathrm{Beam}}(f_0,t_i)=\sqrt{{\mathrm{Re}}^2\left[{\hat{Y}}_{\mathrm{BF}}(f_0,t_i)\right]+{\mathrm{Im}}^2\left[{\hat{Y}}_{\mathrm{BF}}(f_0,t_i)\right]}$

In like manner, instantaneous wave beam drift phase place can be expressed as:

${\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)=\arctan \left\{\frac{\mathrm{Im}\left[{\hat{Y}}_{\mathrm{BF}}(f_0,t_i)\right]}{\mathrm{Re}\left[{\hat{Y}}_{\mathrm{BF}}(f_0,t_i)\right]}\right\}$

Thus, step 3) the single-frequency point beamformer output signal that obtains can be rewritten as polar coordinate representation form, that is:

${\hat{Y}}_{\mathrm{BF}}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)}$

$=A_{\mathrm{Beam}}(f_0,t_i)\cos \widetilde{\mathrm{\Θ}}(f_0,t_i)+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \widetilde{\mathrm{\Θ}}(f_0,t_i)$

So in plural polar coordinates plane, the difference registration process thought of application signal fluctuation phase place, the instantaneous fluctuating difference of Beam Domain output signal vector is carried out to alignment compensation, utilize echo signal and noise to improve the processing gain of spatial domain array in the phase coherence difference of Beam Domain.Now, carry out difference registration process by the wave beam drift phase vectors that three continuous samplings are obtained, can obtain the Beam Domain alignment compensation factor:

${\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)={\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)-2{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-1})+{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-2})$

Because instantaneous amplitude set { A _beam(f ₀, t _i) the beamformer output signal vector of the relevant front and back that rise and fall is equated, so the Beam Domain alignment compensation factor is replaced after former instantaneous wave beam drift phase place, can obtain the beam signal through fluctuating relevant treatment

${\hat{Y}}_{\mathrm{BF}}^{\′}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]$

$=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}}(f_0,t_i)$

Step 5), in step 4) in through the Beam Domain calculated signals wave beam output energy work rate value of fluctuating relevant treatment, thereby the estimation in realize target orientation.

The computing formula of output average power is:

$\mathrm{PFA}\_\mathrm{BF}\left\{Y_{\mathrm{BF}}^{\′}(f,t)\right\}={\mathrm{\Σ}}_j^K{\left\{\mathrm{RE}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2+{\mathrm{\Σ}}_j^K{\left\{\mathrm{Im}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2$

Wherein:

$\mathrm{Re}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}$

$\mathrm{Im}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}.$

After trying to achieve output average power content by above-mentioned formula, just can utilize this performance number to do target Bearing Estimation.

It is more than the description of the key step to the relevant direction estimation method of the Beam Domain based on fluctuating phase alignment of the present invention.Method of the present invention has higher wave beam detection signal-to-noise ratio gain compared with the method for prior art.In a comparative example, the echo signal incident direction of emulation is 60 °, 0 ° to 180 ° of beam scanning angle.For this identical test example, Fig. 3 is frequency domain--the wave beam orientation Output rusults figure that adopts energy measuring target Bearing Estimation method of the prior art to obtain, and Fig. 4 is frequency domain--the wave beam orientation Output rusults figure that the application Beam Domain alignment of the present invention Coherent Targets orientation estimation technique obtains.There is a big difference for the noise background energy distribution of these two kinds of method for estimating target azimuth formed, and the background color in accompanying drawing 4 is darker, and the two approximately differs 15dB left and right.The energy measuring direction estimation method that this has proved during Beam Domain signal phase alignment orientation method of estimation of the present invention compared to existing technology, can obtain higher wave beam detection signal-to-noise ratio gain.

Shown in Fig. 5, be Beam Domain output signal in 60 degree directions, the beam signal phase alignment compensation result at frequency 500Hz place.Fig. 5 (a) is the output energy work rate value of the each sample of this beam signal.Comparison diagram 5 (b) and Fig. 5 (c), instantaneous " linearity " fluctuating phase place of this beam signal has obtained alignment compensation.By " gathering " effect to 0 phase shaft, beamformer output signal is being aimed at incoming wave incident direction, has realized the relevant enhancing of homophase.

Fig. 6 is illustrated in the frequency shown in accompanying drawing 3,4--and wave beam position and orientation matrix output basis is upper, and the broadband signal of choosing frequency range 300 ~ 500Hz scope adds up relevant treatment, the 60 degree arrival bearings' that obtain wave beam output performance result.This figure has proved the inventive method energy measuring method of estimation more of the prior art, has improved the detection performance of 12dB left and right under this target simulator condition.

The present invention also provides the relevant orientation of a kind of Beam Domain based on fluctuating phase alignment estimating system, the long line sonar array that this system forms based on M equally spaced nautical receiving set; This system comprises: module is divided in frequency accumulation, direction guiding vector is asked for module, signal conversion module, fluctuating related process module, energy work rate value computing module; Wherein,

Described frequency accumulation is divided module and is done frequency accumulation division for array element territory, the broadband signal that described sonar array is received, and obtains the array element territory signal of single frequency;

Described direction guiding vector is asked for module for asking for the direction guiding vector of described sonar array incoming wave signal;

Described signal conversion module asks for according to described direction guiding vector the direction guiding vector that module is tried to achieve, and the array element territory signal of the single frequency that described frequency accumulation division module is obtained is transformed into Beam Domain;

The Beam Domain signal that described fluctuating related process module obtains described signal conversion module does fluctuating relevant treatment;

Described energy work rate value computing module is to the Beam Domain calculated signals wave beam output energy work rate value through fluctuating relevant treatment in described fluctuating related process module, thus the estimation in realize target orientation

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 (6)

1. the relevant orientation of the Beam Domain based on a fluctuating phase alignment estimation technique, the long line sonar array that the method forms based on M equally spaced nautical receiving set; The method comprises:

Step 1), array element territory, broadband signal that described sonar array is received does frequency accumulation and divides, and obtains the array element territory signal of single frequency;

Step 2), ask for the direction guiding vector of described sonar array incoming wave signal;

Step 3), according to step 2) the direction guiding vector of trying to achieve, by step 1) the array element territory signal of the single frequency that obtains is transformed into Beam Domain;

Step 4), to step 3) the Beam Domain signal that obtains does fluctuating relevant treatment;

Step 5), in step 4) in through the Beam Domain calculated signals wave beam output energy work rate value of fluctuating relevant treatment, thereby the estimation in realize target orientation.

2. the relevant orientation of the Beam Domain based on the fluctuating phase alignment according to claim 1 estimation technique, is characterized in that described step 2) comprising:

Step 2-1), for single frequency, invisible scanning phase angle theta, obtains the beamformer output signal of sonar array,

Wherein, n _m(f ₀, t) be the additive noise on array element m, τ _m(θ) be incoming wave signal r _m(f ₀, the t) relative time delay of arrival array element m;

Step 2-2), definition beam scanning guiding phase angle range Theta ₁, θ ₂..., θ _d, by invisible scanning phase angle theta _iexpand to whole steering vectors, thereby obtain the direction guiding vector of described sonar array incoming wave signal, this direction guiding vector expression is as follows:

${\widehat{\mathrm{\α}}}_m(f_0,\mathrm{\θ})=\left[\begin{array}{cccc}1& 1& ...& 1\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)}\\ ...& ...& ...& ...\\ e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_1\right)(M-1)}& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_2\right)(M-1)}& ...& e^{-j2\mathrm{\π}{f}_{0}d/c\sin \left({\mathrm{\θ}}_D\right)(M-1)}\end{array}\right].$

3. the relevant orientation of the Beam Domain based on the fluctuating phase alignment according to claim 2 estimation technique, is characterized in that described step 3) comprising:

Step 3-1), array received orientation model while setting single broadband signal incident, its expression formula is as follows:

$y_{\mathrm{BF}}\left(t\right)=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{\inf }\left(t\right)$

$=\underset{i=1}{\overset{K}{\mathrm{\Σ}}}[{\widehat{\mathrm{\α}}}_m(f_i,\mathrm{\θ})s_{f_i}\left(t\right)+n_{f_i}\left(t\right)]$

Wherein, for array to incoming wave signal to specifying frequency f _idirection guiding vector, that centre frequency is f _inarrow band signal, K be split after narrow band signal quantity;

Step 3-2), array beams output signal is transformed to frequency domain form, can obtain the array frequency domain wave beam response of single frequency, invisible scanning phase angle, its expression formula is:

$\hat{Y}=(f_0,{\mathrm{\θ}}_i)=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{e}^{-j2\mathrm{\π}{f}_0{\mathrm{\τ}}_m\left({\mathrm{\θ}}_i\right)}{R}_m\left(f_0\right)+N_m\left(f_0\right)$

$=\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{\widehat{\mathrm{\α}}}_m(f_0,{\mathrm{\θ}}_i)R_m\left(f_0\right)+N_m\left(f_0\right)i=\mathrm{1,2},...,D;$

Wherein,

R _m(f ₀)＝[R ₁(f ₀),R ₂(f ₀),…,R _M(f ₀)] ^T；

N _m(f ₀)＝[N ₁(f ₀),N ₂(f ₀),…,N _M(f ₀)] ^T；

Step 3-3), solve the Beam Domain output signal vector of single frequency, thereby the array element territory signal of realizing single frequency is transformed into Beam Domain, its expression formula is:

$\hat{Y}(f_j,\widetilde{\mathrm{\θ}})=\{\hat{Y}(f_j,{\mathrm{\θ}}_1),\hat{Y}(f_j,{\mathrm{\θ}}_2),...,\hat{Y}(f_j,{\mathrm{\θ}}_D)\}j=\mathrm{1,2},...,K.$

4. the relevant orientation of the Beam Domain based on the fluctuating phase alignment according to claim 3 estimation technique, is characterized in that described step 4) comprising:

Step 4-1), ask for the Beam Domain output signal of single frequency at the instantaneous amplitude envelope A of a certain sampling instant _beam(f ₀, t _i) and instantaneous wave beam drift phase place

Step 4-2), according to step 4-1) result of calculation the expression formula of single frequency Beam Domain output signal is rewritten as to polar coordinate representation form;

${\hat{Y}}_{\mathrm{BF}}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)}$

$=A_{\mathrm{Beam}}(f_0,t_i)\cos \widetilde{\mathrm{\Θ}}(f_0,t_i)+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \widetilde{\mathrm{\Θ}}(f_0,t_i)$

Step 4-3), in plural polar coordinates plane, the difference alignment disposal route of application signal fluctuation phase place, carries out alignment compensation by the instantaneous fluctuating difference of Beam Domain output signal vector, obtains the Beam Domain alignment compensation factor;

${\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)={\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_i)-2{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-1})+{\widetilde{\mathrm{\Θ}}}_{\mathrm{Beam}}(f_0,t_{i-2})$

Step 4-4), by step 4-3) the Beam Domain alignment compensation factor that obtains replaces the instantaneous wave beam drift phase place in the Beam Domain output signal of single frequency, obtains the beam signal through fluctuating relevant treatment;

${\hat{Y}}_{\mathrm{BF}}^{\′}(f_0,t_i)=A_{\mathrm{Beam}}(f_0,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]+{\mathrm{jA}}_{\mathrm{Beam}}(f_0,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)\right]$

$=A_{\mathrm{Beam}}(f_0,t_i)\·e^{j{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_0,t_i)}.$

5. the relevant orientation of the Beam Domain based on the fluctuating phase alignment according to claim 4 estimation technique, is characterized in that, in described step 5) in, the computing formula of energy work rate value is:

$\mathrm{PFA}\_\mathrm{BF}\left\{Y_{\mathrm{BF}}^{\′}(f,t)\right\}={\mathrm{\Σ}}_j^K{\left\{\mathrm{Re}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2+{\mathrm{\Σ}}_j^K{\left\{\mathrm{Im}\right[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\left]\right\}}^2$

Wherein:

$\mathrm{Re}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\cos \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}$

$\mathrm{Im}\left[\frac{{\mathrm{\Σ}}_i^N{Y}_{\mathrm{BF}}^{\′}(f_j,t_i)}{N}\right]=\frac{{\mathrm{\Σ}}_i^N{A}_{\mathrm{Beam}}(f_j,t_i)\sin \left[{\widetilde{\mathrm{\Ψ}}}_{\mathrm{Beam}}(f_j,t_i)\right]}{N}.$

6. the relevant orientation of the Beam Domain based on a fluctuating phase alignment estimating system, is characterized in that, the long line sonar array that this system forms based on M equally spaced nautical receiving set; This system comprises: module is divided in frequency accumulation, direction guiding vector is asked for module, signal conversion module, fluctuating related process module, energy work rate value computing module; Wherein,

Described frequency accumulation is divided module and is done frequency accumulation division for array element territory, the broadband signal that described sonar array is received, and obtains the array element territory signal of single frequency;

Described direction guiding vector is asked for module for asking for the direction guiding vector of described sonar array incoming wave signal;

Described signal conversion module asks for according to described direction guiding vector the direction guiding vector that module is tried to achieve, and the array element territory signal of the single frequency that described frequency accumulation division module is obtained is transformed into Beam Domain;

The Beam Domain signal that described fluctuating related process module obtains described signal conversion module does fluctuating relevant treatment;

Described energy work rate value computing module is to the Beam Domain calculated signals wave beam output energy work rate value through fluctuating relevant treatment in described fluctuating related process module, thus the estimation in realize target orientation.