Single-vector hydrophone DOA dynamic estimation method based on phase-locked loop

Abstract

The invention provides a single vector hydrophone DOA dynamic estimation method based on a phase-locked loop, and belongs to the field of sonar signal processing. A single-vector hydrophone DOA open-loop estimation algorithm is used as a phase discriminator, a phase-locked loop is used for dynamically estimating the direction of arrival of a signal, accurate tracking of DOA is kept in a dynamic scene, the problem that a traditional single-vector hydrophone DOA estimation method is not high in precision in the dynamic scene is solved, and the estimation accuracy of the DOA is improved. And outputting an in-phase branch of the phase-locked loop phase discriminator as the optimal synthesis of the vibration velocity. The method is not only small in calculation amount, but also capable of tracking the signal incoming wave direction in real time. And when # imgabs0 # iteratively approaches 0, the in-phase branch of the phase-locked loop phase discriminator is the optimal synthesis of the vibration velocity.

Description

Technical Field

[0001] The invention belongs to the field of sonar signal processing, and in particular relates to a single-vector hydrophone DOA dynamic estimation method based on a phase-locked loop. Background Art

[0002] The complexity and variability of underwater acoustic channels are the biggest challenges for underwater acoustic communication and measurement. The single vector hydrophone (SVH) consists of a non-directional sound pressure sensor and a dipole-directional particle velocity (acceleration) sensor, which can simultaneously measure the sound pressure and particle velocity information at a certain point in the sound field. A single vector hydrophone can estimate the direction of arrival (DOA) of the sound source and obtain the azimuth information of the measurement target, with good spatial directivity. Based on the azimuth estimation of the signal, the sound pressure and velocity output of the vector hydrophone can obtain a spatial gain of 4.8dB-6dB in the isotropic noise field after weighted processing.

[0003] At present, single vector hydrophone DOA estimation methods include open-loop estimation methods such as average sound intensity meter, complex sound intensity meter and active average sound intensity meter. These methods are based on data batch processing, segmented estimation of the direction of the sound source wave, and then electronic rotation to form a vibration velocity combination, without using historical data information. In practical applications, due to the rotation of the receiving end on the sea surface or the relative motion between the transmitter and the receiver, the direction of the sound source relative to the vector hydrophone changes over time. At this time, the performance of the above single vector hydrophone DOA estimation method will be limited, and there is a problem of low accuracy in dynamic scenes. Summary of the invention

[0004] The purpose of the present invention is to provide a single vector hydrophone DOA dynamic estimation method based on a phase-locked loop, which utilizes a single vector hydrophone DOA open-loop estimation algorithm as a phase detector, and adopts a phase-locked loop to dynamically estimate the incoming direction of the signal, thereby maintaining accurate tracking of the DOA in dynamic scenes, overcoming the problem of low accuracy in dynamic scenes in traditional single vector hydrophone DOA estimation methods, and outputting the in-phase branch of the phase-locked loop phase detector as the optimal synthesis of the vibration velocity.

[0005] The specific technical solution is that the present invention provides a single vector hydrophone DOA dynamic estimation method based on a phase-locked loop, comprising the following steps:

[0006] Step 1: The velocity vector (v x , v y ) to rotate electronically, the rotation angle is Get v s and v c ,

[0007]

[0008]

[0009] Among them, v x and v y are the vibration velocity signals along the x-axis and y-axis received by the single vector hydrophone, is the estimated value of the azimuth angle of the signal output by the numerically controlled oscillator (NCO);

[0010] Step 2: Use the single-vector hydrophone DOA open-loop estimation algorithm as a phase detector to estimate θ e ,in θ is the azimuth of the signal, with the positive direction of the hydrophone x-axis as zero degrees;

[0011] Step 3: θ e The open-loop estimate of Perform loop filtering and output frequency control value f(t);

[0012] Step 4: Frequency control f(t) controls NCO generation

[0013] Step 5: Based on the negative feedback characteristics of the phase-locked loop, when When the iteration approaches 0, That is, the DOA real-time estimation and dynamic tracking results, output azimuth estimation value Output speed combination v c and v s .

[0014] In the step 2, the single vector hydrophone DOA open-loop estimation algorithm that realizes the phase detector function in the phase-locked loop includes an average sound intensity device, a complex sound intensity device and an active average sound intensity device.

[0015] When the open-loop estimation algorithm used is an average sound intensity detector, the step 2 specifically includes the following contents:

[0016] The sound pressure channel signal p(t) is respectively c and v s Do the related operation and get I x and I y ,

[0017]

[0018]

[0019] Where T is the relevant integration time, is the received signal power of the hydrophone, Δ x and Δ y is the noise component;

[0020] Find the inverse tangent and get θ e Estimated value of where tan -1 () is the inverse tangent function.

[0021] In step three, the loop filtering may adopt a first-order or second-order IIR filter.

[0022] The present invention provides a single vector hydrophone DOA dynamic estimation method based on a phase-locked loop. The single vector hydrophone DOA open-loop estimation such as an average sound intensity meter, a complex sound intensity meter or an active average sound intensity meter is used as a phase detector, and a phase-locked loop is used to dynamically track the direction of the signal. This method not only has a small amount of calculation, but also can track the direction of the signal in real time. When the iteration approaches 0, the in-phase branch of the phase-locked loop phase detector is the optimal synthesis of the vibration speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the flow chart of the DOA estimation method of the present invention.

[0024] Figure 2 It is a principle block diagram of the DOA estimation method of the present invention.

[0025] Figure 3 For uniform circular motion, T = 0.1s, loop bandwidth B L The root mean square curve of the azimuth estimation error at different times.

[0026] Figure 4 This is a comparison chart of the DOA estimate and the true direction value when SNR = 10dB in a uniform circular motion scene.

[0027] Figure 5 This is a comparison chart of the DOA estimate and the true azimuth value when SNR = -10dB in a uniform circular motion scenario.

[0028] Figure 6 In the uniform linear motion scenario, T = 0.1s, B L The root mean square curve of the azimuth estimation error at different times.

[0029] Figure 7 This is a comparison chart of the DOA estimate and the true azimuth value when SNR = 10dB in a uniform linear motion scenario.

[0030] Figure 8 This is a comparison chart of the DOA estimate and the true azimuth value when SNR = -10dB in a uniform linear motion scenario. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] like Figure 1 and Figure 2 As shown, the steps of the present invention are as follows:

[0033] (1) Based on the estimated value of the orientation v x 、v y Perform electron rotation to obtain v s and v c ,

[0034]

[0035]

[0036] Among them, v x and v y are the vibration velocity signals along the x-axis and y-axis received by the single vector hydrophone, The signal output by the numerically controlled oscillator (NCO) is the estimated value of the azimuth angle θ.

[0037] (2) Using the average sound intensity detector in the single-vector hydrophone DOA open-loop estimation as a phase detector, estimate Specifically include:

[0038] a. Compare the sound pressure channel signal p(t) with v c and v s Do the related operation and get I x and I y ,

[0039]

[0040]

[0041] Where T is the relevant integration time, is the received signal power of the hydrophone, Δ x and Δ y is the noise component.

[0042] b. For I x and I y Find the inverse tangent and get an estimate of θ where tan -1 () is the inverse tangent function.

[0043] (3) Loop filtering. Since the dynamics in marine applications are small, a second-order phase-locked loop can meet the dynamic tracking requirements of underwater acoustic applications. In this case, the loop filter uses a first-order IIR filter. The input of the loop filter is The output is the frequency control quantity f(t), and its transfer function is F(z).

[0044]

[0045] Where C 1 , C 2 By loop parameters (B L , ζ, k) are calculated, where B L is the loop bandwidth, ζ is the damping coefficient, and k is the loop gain.

[0046] (4) The frequency control quantity f(t) controls the output phase θ(t) of the numerically controlled oscillator to realize the integral operation.

[0047]

[0048] θ(t) is the above-mentioned estimated value of the direction

[0049] (5) The negative feedback characteristics of the phase-locked loop make When the iteration approaches 0, That is the result of real-time DOA estimation and dynamic tracking. At this time, the in-phase branch of the phase-locked loop phase detector is the optimal synthesis of the vibration velocity.

[0050] Simulation study of the present invention:

[0051] The simulation is based on the two-dimensional output model of a single vector hydrophone, using an average sound intensity detector as a phase detector, and is performed for both circular and linear motion scenarios.

[0052] (1) The signal source performs uniform circular motion around the hydrophone.

[0053] Figure 3 Set the relevant integration time T = 0.1s, B L The root mean square (RMSE) of the azimuth estimation error at different SNRs at 0.1 Hz, 0.3 Hz and 0.5 Hz are taken respectively. Figure 4 and Figure 5 The following are comparison diagrams of DOA estimation and true value when SNR=10dB and -10dB in uniform circular motion scenario. As shown in the figure, when SNR>0dB, different loop bandwidths B L The RMSE of DOA estimation is less than 1°, which has high dynamic tracking accuracy.

[0054] (2) The signal source passes near the hydrophone at a uniform speed in a straight line. The hydrophone is placed at the origin, and the angle between the route and the x-axis of the hydrophone is set to 60°.

[0055] Figure 6 The loop bandwidth is B L Taking 0.1 Hz, 0.3 Hz and 0.5 Hz, and the correlation integration time T = 0.1 s, the root mean square (RMSE) of the azimuth estimation error with different SNRs is obtained. Figure 7 , Figure 8The following are the comparison diagrams of DOA estimation and true value when SNR=10dB and -10dB in uniform linear motion scene. As can be seen from the figure, when SNR>0dB, different B L The RMSE of DOA estimation is less than 1°, which has high dynamic tracking accuracy.

[0056] It should be pointed out that although the simulation study was conducted only with the average sound intensity detector as the phase detector, the phase-locked loop-based single-vector hydrophone DOA dynamic estimation method provided by the present invention is an algorithm framework that is compatible with various DOA open-loop estimation methods, and these open-loop estimation methods can all be used to realize the phase detector function in the loop.

[0057] In summary, the phase-locked loop-based single-vector hydrophone DOA dynamic estimation method provided by the present invention can track the direction of arrival of the signal with high precision in different dynamic scenarios. When the iteration approaches 0, the in-phase branch of the phase-locked loop phase detector is the optimal synthesis of the vibration speed v c .

Claims

1. A single-vector hydrophone DOA dynamic estimation method based on a phase-locked loop, characterized in that: The steps include: Step 1: The velocity vector (v x ,v y ) to rotate electronically, the rotation angle is Get v s and v c : Among them, v x 、v y are the vibration velocity signals along the x-axis and y-axis received by the single vector hydrophone SVH, It is the estimated value of the azimuth angle of the signal output by the numerically controlled oscillator NCO; Step 2: Use the single-vector hydrophone DOA open-loop estimation algorithm as a phase detector to estimate θ e ,in θ is the azimuth of the signal, with the positive direction of the hydrophone x-axis as zero degrees; Step 3: θ e The open-loop estimate of Perform loop filtering and output frequency control value f(t); Step 4: The frequency control quantity f(t) controls the generation of the numerically controlled oscillator NCO Step 5: Based on the negative feedback characteristics of the phase-locked loop, when When the iteration approaches 0, That is, the DOA real-time estimation and dynamic tracking results, output azimuth estimation value Output speed combination v c and v s .

2. According to the phase-locked loop-based single-vector hydrophone DOA dynamic estimation method of claim 1, it is characterized in that: The single vector hydrophone DOA open-loop estimation algorithm in step 2 is the average sound intensity detector method.

3. The method for dynamic estimation of DOA of a single vector hydrophone based on a phase-locked loop according to claim 1, characterized in that: The single vector hydrophone DOA open-loop estimation algorithm in step 2 is an active average sound intensity detector method.

4. The method for dynamic estimation of DOA of a single vector hydrophone based on a phase-locked loop according to claim 1, characterized in that: The single-vector hydrophone DOA open-loop estimation algorithm in step 2 is a complex sound intensity detector method.

5. The method for dynamic estimation of DOA of a single vector hydrophone based on a phase-locked loop according to claim 2, characterized in that: The step 2, when implemented specifically, includes the following steps: The sound pressure channel signal p(t) is respectively c and v s Do the related operation and get I x and I y , Where T is the relevant integration time, is the received signal power of the hydrophone, Δ x and Δ y is the noise component; Find the inverse tangent and get θ e Estimated value of where tan -1 ( ) is the inverse tangent function.

6. The method for dynamic estimation of DOA of a single vector hydrophone based on a phase-locked loop according to claim 1, characterized in that: The loop filtering in step three adopts a first-order or second-order IIR filter.

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