JPH06347530A - Estimation system for sound source position in water - Google Patents

Abstract

PURPOSE:To reduce the number of arranged wave receivers. CONSTITUTION:Delay correlation processors 1a-1c calculate the delay correlation degree between two wave reception signals among reception signals of three wave receivers which are linearly arranged in depthwise direction at such a wide interval enough to measure the arrival time difference of acoustic wave. A propagation calculator 2 computes the wave reception signals for respective virtual sound sources of the wave receivers based on the depths Z1-Z3 of wave receivers, virtual sound source positions P11-PXZ and one wave reception signal. Delay correlation processors calculate the delay correlation degree between the computed two wave reception signals. The similarity on these two delay correlations are calculated by similarity calculators 4a-4c, and when the similarity exceeds a specified level the virtual sound source position corresponding to the delay correlation degree at this time is detected by position detectors 5a-5b, then the results are successively stored in a memory 6. An output processor 7 performs access to its memory to extract virtual sound source positions concentrating in a certain position and outputs information such as their positions and similarity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater sound source position estimating system for estimating a sound source position in water.

[0002]

2. Description of the Related Art The sound source position of an underwater sound wave is specified by the depth and the horizontal distance to the measurement point. However, since the propagation path in water is complicated, the underwater sound source position estimation system linearly arranged in the depth direction. The sound source position is estimated using a plurality of wave receivers. As an underwater sound source position estimation system of this type, the one shown in FIG. 4 is conventionally known.

In FIG. 4, N wave receivers (# 1 to #)
N) are arranged linearly at regular intervals in the depth direction.
The frequency analyzer 10 converts each of the received signals of these N receivers into a frequency axis, and obtains an energy distribution E ₀ on the arrayed receiver for a specific frequency f ₁ ,
It is applied to one input of the similarity calculator 12.

On the other hand, in the propagation calculator 11, the data of the depth (Z _{1 to} Z _N ) of each receiver and the virtual sound source position (P ₁₁ to Z _N ).
P _XZ ) data and is given from the outside. Here, the virtual sound source position (P _{11 to} P _XZ ) is N as shown in FIG. 5, for example.
This is the coordinate position of each lattice when a virtual lattice plane parallel to the array direction of the individual wave receivers is set in the sound field, and a sound source is virtually arranged in each lattice.

In this propagation calculator 11, since the horizontal distance between each virtual sound source position and each wave receiver is known, the depth data of each wave receiver and the data of each virtual sound source position are received, and F
Propagation loss in the case where each of the N wave receivers receives the sound wave of the virtual sound source existing at each position of P _{11 to} P _XZ by the FT process is calculated for the specific frequency f ₁ , and the specific frequency is calculated. The energy distribution (E _{11 to} E _XZ ) on the array receiver of is given to the other input of the similarity calculator 12.

In the similarity calculator 12, the energy distribution E _{0 of the} sound waves measured by the N number of receivers (frequency analyzer 10
Output) of each of the N receivers obtained by the propagation calculation, the similarity of the energy distributions of E _{11 to} E _XZ is calculated using an estimation method such as the maximum likelihood estimation method or the least squares method, and the similarity of each is calculated. The degree is output to the position detector 13.

For example, in FIG. 5, three energy distributions (a), (b) and (c) are shown on the arrayed wave receiver, but (a) shows sound waves measured by N wave receivers. Energy distribution E ₀ , (a) is the energy distribution by the propagation calculation for the virtual sound source b arranged at the lattice position close to the position of the true sound source a, and (c) is the virtual sound source arranged at the grid position far from the position of the true sound source a It is an energy distribution by the propagation calculation with respect to c.

In the similarity calculator 12, (a) and (a),
(A) and (c) are compared with each other to obtain the respective similarities, but the virtual sound source b located near the true sound source a is located.
It can be seen that the degree of similarity indicates a value higher than the degree of similarity of the virtual sound source c at a distant position.

The position detector 13 detects a virtual sound source position (lattice point position) at which a similarity exceeding a preset level and its energy distribution are generated, and supplies it to the output processor 14.

The output processor 14 estimates the sound source position in consideration of the magnitude relation of the degree of similarity, the temporal continuity and the like.

[0011]

In the above-mentioned conventional underwater sound source position estimation system, in the similarity calculation process of the calculation data for estimating the true sound source position from the virtual sound source position and the measurement data, the underwater sound field Although the energy distribution on the array receiver set in the depth direction is used as comparison data, the difference in the calculation data with respect to the virtual sound source position is small, so the similarity calculation process can be used to calculate In order to be able to extract the data corresponding to the true sound source position from, the detailed measured value of the energy distribution is required as the comparison target of the calculation data. On the other hand, although there are various frequencies of the sound waves emitted from the sound source, the array interval of the wave receivers must be determined according to the law of half-wavelength so that the sound waves of the assumed minimum wavelength can be accurately received.

Therefore, in the conventional underwater sound source position estimating system, it is necessary to arrange a considerably large number of wave receivers in the depth direction, and there is a problem that the system scale increases.

The present invention has been made in view of such a problem, and an object thereof is to provide an underwater sound source position estimation system capable of significantly reducing the number of receivers of an array receiver. .

[0014]

In order to achieve the above object, the underwater sound source position estimating system of the present invention has the following configuration. That is, the underwater sound source position estimation system of the present invention includes a plurality of wave receivers linearly arranged in the depth direction at intervals that are spaced apart so that the arrival time difference of sound waves can be measured; One or three or more first delay correlation processors that calculate the degree of delay correlation between the received signals of the wave receivers; and virtually on each lattice of a virtual lattice plane parallel to the arrangement direction of the plurality of wave receivers. Calculates the propagation loss for each frequency when the sound waves of the arranged virtual sound source are received by each of the plurality of wave receivers, converts it to the received signal for each virtual sound source of each wave receiver, and outputs it. A propagation calculator for calculating one or more second delay correlation processors for calculating the degree of delay correlation between two received signals of the plurality of receivers output by the propagation calculator A delay correlation degree calculated by the first delay correlation processor and a second delay correlation degree; 1 or 3 or more similarity calculators that calculate the similarity with the delay correlation degree calculated by the delay correlation processor; and output a virtual sound source position corresponding to the delay correlation degree when the similarity becomes a certain level or more. 1 or 3 or more position detectors; a memory that sequentially stores the virtual sound source positions detected by the detector; a virtual sound source position that is concentrated at a certain position among the stored virtual sound source positions; And an output processor for outputting information such as position and similarity.

[0015]

Next, the operation of the underwater sound source position estimating system of the present invention configured as described above will be described. The plurality of wave receivers linearly arranged in the depth direction are arranged at intervals so that the arrival time difference of the sound waves can be measured and receive the sound wave of the true sound source. The degree of delayed correlation between the wave signals is calculated by the first delayed correlation processor. On the other hand, the propagation calculator calculates the received signal for each virtual sound source of each receiver,
The calculated degree of delay correlation between the received signals of the two receivers is calculated by the second correlation processor. The similarity of these two delay correlations is calculated by the similarity calculator, and the virtual sound source position corresponding to the delay correlation when the similarity exceeds a certain level is detected by the position detector and sequentially stored in the memory. To be done. Then, of the stored virtual sound source positions, virtual sound source positions that are concentrated at a certain location are extracted, and information such as the position and the degree of similarity is output from the output processor.

In summary, since the comparison data used in the similarity calculation process according to the present invention is not the data distribution in the spatial domain as in the conventional case but the data distribution in the time domain as in the conventional case, It is not necessary to measure the detailed data distribution.

Therefore, the number of wave receivers of the array wave receiver can be greatly reduced, and the system scale can be reduced.
It should be noted that the number of wave receivers may be two as long as the estimation accuracy does not matter, and a minimum of three is sufficient even if a certain accuracy is secured.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an underwater sound source position estimation system according to an embodiment of the present invention. Some of the components have the same names as those of the conventional example (FIG. 4), but the operation contents are different.

This embodiment shows an example in which three wave receivers # 1 to # 3 are used. These three wave receivers are linearly arrayed in the depth direction, but differ from the prior art in that the array intervals are sufficiently separated so that the difference in arrival time of sound waves can be measured.

The received signals of these three receivers are not subjected to the filtering process, that is, in the state where the broadband property is maintained (first
No. 1) is input to the delay correlation processor, and one of the received signals is input to the propagation calculator 2.

The (first) delay correlation processors are 1a and 1b.
And 1c, the delay correlation degree between two received signals of the received signals of the three receivers is calculated.

That is, the delayed correlation processor 1a is the receiver # 1.
And the delay correlation D _a0 (τ) between the received signals of # 2 and # 2 is calculated. Similarly, the delay correlation processor 1b is the same as the receiver # 2.
The delayed correlation degree D _b0 (τ) between the three received signals is calculated, and the delayed correlation processor 1c calculates the delayed correlation degree D _c0 (τ) between the received signals of the receivers # 1 and # 3. calculate.

Further, in the propagation calculator 2, the data of the depths (Z _{1 to} Z ₃ ) of the respective wave receivers and the data of the virtual sound source positions (P _{11 to} P _XZ ) are given from the outside as in the conventional case. Further, the received signal of one of the three wave receivers is input while maintaining its wide band property, and unlike the conventional case, the following four operations are sequentially executed. The virtual sound source position (P _{11 to} P _XZ )
Is the same as the conventional one.

(1) Of the received signals (measurement signals) of the three receivers having the waveforms shown in the right side of FIG. 2, for example, the measured signal of one receiver, for example, the received wave If the measurement signal of the device # 3 is given as a reference signal, it is converted into a frequency axis by FFT processing, and the spectrum level of the measurement signal at the position of the receiver # 3 that issued the reference signal is obtained.

(2) Propagation of each propagation path from each virtual sound source position to the receiver # 3 based on the data of the virtual sound source position (P _{11 to} P _XZ ) and the data of the depth Z ₃ of the receiver # 3. The loss amount is calculated for each frequency and added to the spectrum level of the measurement signal to obtain the sound source spectrum level at each virtual sound source position.

(3) Depth of each receiver (Z ₁ , Z ₂ , Z
₃ ) Calculate the propagation loss amount for each propagation path corresponding to each receiver position for each frequency based on the data of ₃ ), add the loss amount to the sound source spectrum level at each virtual sound source position, and calculate each virtual sound source position. Obtain the spectral level at each receiver position for.

(4) The spectrum level at each receiver position is converted to the time axis by the IFFT processing, and as shown on the left side of FIG. 2, the broadband property at each receiver position for each virtual sound source position is obtained. The received wave signal (the signal obtained by the propagation calculation) that is held is obtained.

Next, the (second) delay correlation processor 3a
, 3b and 3c, each of which is a propagation calculator 2
Calculates the delay correlation between two wave-received signals of the wave-received signals (the signals obtained by the propagation calculation) of the three wave receivers.

That is, the delay correlation processor 3a is provided with the receiver # 1.
And the delay correlation between received signals of # 2 (D _a11 (τ) ~ D
_{Calculate aXZ} (τ)). Similarly, the delay correlation processor 3b
Is the degree of delay correlation between the received signals of the receivers # 2 and # 3 (D
_b11 (τ) to D _bXZ (τ)) are calculated. The delay correlation processor 1c calculates the degree of delay correlation (D _c11 (τ) to D _cXZ (τ)) between the received signals of the receivers # 1 and # 3.

The similarity calculator is composed of three units, 4a, 4b and 4c, and the similarity between the delay correlations output by both delay correlation processors is estimated by a maximum likelihood estimation method or a least squares method. Calculate using.

That is, the similarity calculator 4a calculates the delay correlation degree D _a0 (τ) from the delay correlation processor 1a and the delay correlation processor 3a.
_Compute the similarity with the degree of delayed correlation from a (D _a11 (τ) to D _aXZ (τ)). The similarity calculator 4b is a delay correlator 1b.
From the delay correlator D _b0 (τ) to the delay correlator (D _b11 (τ) to D _bXZ (τ)) from the delay correlator 3 b. The similarity calculator 4c calculates the similarity between the delay correlation degree D _c0 (τ) from the delay correlator 1c and the delay correlation degree (D _c11 (τ) to D _cXZ (τ)) from the delay correlator 3a. To do.

For example, assuming that the three wave receivers and the true sound source or the virtual sound source have the positional relationship shown in FIG. 3 (A), the delay correlation processor 1a, as shown in FIG. 3 (B), The degree of delay correlation between the measurement signal of the receiver # 1 and the measurement signal of the receiver # 2 for the true sound source a is obtained.

On the other hand, in the delay correlation processor 3a, as shown in FIG.
As shown in (C), the degree of delay correlation between the propagation calculation signal of the wave receiver # 1 and the propagation calculation signal of the wave receiver # 2 for the virtual sound source b located near the true sound source a is obtained, and as shown in FIG.
As shown in (D), the degree of delay correlation between the propagation calculation signal of the wave receiver # 1 and the propagation calculation signal of the wave receiver # 2 for the virtual sound source c located far from the true sound source a is obtained.

Therefore, in the similarity calculator 4a, as shown in FIG.
The shape of the delay correlation degree measured by (B) and the shape of the delay correlation degree calculated by the propagation calculation of FIG. 3C are compared, and FIG.
The shape of the delay correlation degree measured by (B) and the shape of the delay correlation degree calculated by the propagation calculation of FIG. 3D are compared, and respective comparison results (similarity) are output. In the illustrated example, the degree of delay correlation corresponding to the virtual sound source b indicates a greater degree of similarity.

The position detector is composed of three elements 5a, 5b and 5c. The position detector 5a receives the output of the similarity calculator 4a and the position detector 5b receives the output of the similarity calculator 4b. The output of the similarity calculator 4c is input to the position detector 5c, and the position of the virtual sound source that produces the degree of similarity exceeding the set level and its delayed correlation is detected.

The detection outputs of these three position detectors are sequentially stored in the memory 6, respectively. As can be inferred from the above description, the memory 6 has one of three virtual sound source positions. Alternatively, a plurality of virtual sound source positions are stored in a duplicated form.

Therefore, the output processor 7 accesses the memory 6 to extract overlapping virtual sound source positions, and outputs information such as the positions (lattice coordinate positions) of the extracted virtual sound sources and corresponding similarities. The position (depth and horizontal distance) of the true sound source a is estimated from this output information.

It should be noted that the underwater sound source generally emits sound waves in various states including continuous waves and pulse waves, but if three wave receivers are used, as described above, virtual waves are generated in the virtual lattice plane. Since one block of the sound source position can be extracted, the position can be estimated regardless of the kind of the sound source, and the accuracy is improved as the number of receivers is further increased.

On the other hand, when there are two wave receivers, each of the three delay correlation processors has one system, but when the sound source also emits a pulse wave, the virtual sound source position showing the maximum level is It may be difficult to estimate the position of the sound source due to the large number of points detected over a wide range, but it is possible to know the range of existence of the sound source. Estimates are possible.

[0040]

As described above, in the underwater sound source position estimating system of the present invention, attention is paid to the difference in the arrival time of the sound source signal generated between the two receivers in the similarity calculation process of the measurement data and the calculation data, Since the delay correlation is used as comparison data, it is not necessary to measure spatially detailed data distribution as in the conventional case, and the number of array receivers can be significantly reduced. This has the effect of reducing the system scale.

[Brief description of drawings]

FIG. 1 is a block diagram of a configuration example of an underwater sound source position estimation system of the present invention.

FIG. 2 is an operation explanatory diagram of a propagation calculation process of the present invention.

FIG. 3 is an operation explanatory diagram of the similarity calculation processing of the present invention,
(A) is a positional relationship diagram between an array wave receiver and a sound source, (B) is an explanatory diagram of a delay correlation degree for a true sound source a, (C) is an explanatory diagram of a delay correlation degree for a virtual sound source b, (D) 8] is an explanatory diagram of a degree of delay correlation for a virtual sound source c.

FIG. 4 is a configuration block diagram of a conventional underwater sound source position estimation system.

FIG. 5 is an operation explanatory diagram of a conventional similarity calculation process.

[Explanation of symbols]

 1a Delay Correlation Processor 1b Delay Correlation Processor 1c Delay Correlation Processor 2 Propagation Calculator 3a Delay Correlation Processor 3b Delay Correlation Processor 3c Delay Correlation Processor 4a Similarity Calculator 4b Similarity Calculator 4c Similarity Calculator 5a Position detector 5b Position detector 5c Position detector 6 Memory 7 Output processor

Claims (1)

[Claims] 1. A plurality of wave receivers linearly arrayed in the depth direction at intervals that are spaced apart so that a difference in arrival time of sound waves can be measured; and received signals of two wave receivers in the plurality of wave receivers. One or three or more first delay correlation processors for calculating the degree of delay correlation between two or more; and a sound wave of a virtual sound source virtually arranged on each lattice of a virtual lattice plane parallel to the array direction of the plurality of wave receivers. A propagation calculator that calculates, for each frequency, a propagation loss when each of the plurality of wave receivers receives a wave, and converts the propagation loss into a wave reception signal for each virtual sound source of each wave receiver and outputting the wave reception signal; One or three or more second delay correlation processors that calculate the degree of delay correlation between two received signals of the received signals of the plurality of receivers output from the propagation calculator; and the first delayed correlation. The degree of delay correlation calculated by the processor and the delay calculated by the second delay correlation processor 1 to calculate the similarity between Sekido
Or 3 or more similarity calculators; 1 or 3 or more position detectors that output virtual sound source positions corresponding to the degree of delay correlation when the similarity is a certain level or more; virtual detected by the detectors A memory for sequentially storing sound source positions;
An underwater sound source position estimation, comprising: an output processor that extracts virtual sound source positions that are concentrated at a fixed location from the stored virtual sound source positions and outputs information such as the position and similarity degree; system.