JP2000266833A - Apparatus and method for acoustic positioning for running noise performing doppler correction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method, for an acoustic positioning operation for a sailing noise performing a Doppler correction, in which the sailing noise generated by a sailing body is received by a plurality of receivers on the basis of a fact that the running speed of a sound source is found from a received signal by a receiver, and in which the position of the running body is detected. SOLUTION: In this positioning apparatus, the radiant noise of a running body is received by two or more receivers, and the direction of a sound source is found by finding a correlation between received signals. The apparatus is constituted in such a way that a receiver A 5, a receiver B 6, a receiving circuit 7, a receiving circuit 8, an A/D converter 9, an A/D converter 10, an FFT processor 11, an FFT processor 12, a storage device 13, a storage device 14, a frequency band detector 15 for a running noise caused by the vibration characteristic of the running body, a band-pass filter processor 16, a band-pass filter processor 17, a sailing- body speed detector 18 by a Doppler frequency, a Doppler-correction computing unit 19, a correlation computing unit 20, and a display 21, are provided. Then, when the sound source is running at high speed, the influence of a Doppler effect generated between received signals received by two or more receivers is corrected, the maximum value of the correlation between the respective received signals is calculated precisely, the difference in the arrival time up to the respective receivers of the radiant noise of the running body is detected, and the position of the sound source is specified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic positioning apparatus and method for measuring a position of a vehicle using radiation noise of the vehicle.

[0002]

2. Description of the Related Art A conventional acoustic positioning device is disclosed in Document 1: "Ocean acoustics (basic and applied)". 209-21
And Patent Document 2: Patent Publication No. 2723866 "Title of Invention: Signal Detector", and the principle is the SBL positioning method or SS disclosed in Document 1.
It is the same as the BL method. The block diagram of the device disclosed in Document 1 is shown in FIG. 2, and FIGS. 3, 4 and 5 are shown in order to explain the principle and the like.

In FIG. 2, 1 is underwater, 2 is the water surface, 3 is the sea floor, 4 is the vehicle, 5 is the receiver A, 6 is the receiver B, 7,.
8 is a receiving circuit, 9 and 10 are A / D converters, 20 is a cross-correlation calculator, and 21 is a display.

[0004] The operation of each component will be described below.

[0005] When the traveling body 4 is traveling in the water 1 and the water surface 2, the traveling noise is generated from the traveling body 4, and the signals received by the receivers A 5 and B 6 are received. Are amplified to a certain level by the receiving circuits 7 and 8, and then input to the A / D converters 9 and 10. Here, the analog signal is converted into a digital signal and input to the cross-correlation calculating unit 20.
The cross-correlation calculator 20 performs a cross-correlation process on the received signals A and B, which are digital signals sent from the A / D converters 9 and 10, as shown in FIG. Ask for. Further, the azimuth and position of the sound source are measured from the arrival time difference between the received signal A and the received signal B shown in FIGS. 4 and 5, and the result is displayed on the display 21.

Document 2 uses broadband noise including radiated noise of a vehicle in place of the pinger sound in the principle disclosed in Document 1, and uses wideband noise received by receivers arranged at two different places. The present invention relates to a signal detection device that corrects the influence of the Doppler effect accompanying the movement of a sound source generated in noise. That is, a plurality of Doppler correction units for time-compressing or expanding one input signal of one of the signals received at the two locations at a plurality of predetermined ratios, respectively, and a cross-correlation between outputs of the plurality of Doppler correction units and the other signal. And a maximum selector for selecting the maximum value from the output of each cross-correlator. With reference to FIG. 3, the conventional invention disclosed in Reference 2 will be described using mathematical expressions.

The waveforms received by the receivers arranged at two different locations are represented by the following equations. Assuming that s (t) is an amplitude obtained by removing noise and the Doppler effect from the received signal of the receiver A5 at time t, the received waveform x of the receiver A5 and the receiver B6
₁ (t) and x ₂ (t) include the Doppler effect and are expressed by the following equations.

[0008]

(Equation 1)

[0009]

(Equation 2)

D (t): difference in arrival time of navigation noise between receivers A and B at time t n ₁ (t): Gaussian white noise n ₂ (t) received by receiver A5 at time t : Gaussian white noise n ₁ (t) and n ₂ (t) received by the receiver B6 at time t are uncorrelated.

Here, the invention disclosed in Document 2 discloses a method of correcting the Doppler frequency of one of the waveforms in order to make the frequencies of the received waveforms of the receivers A5 and B6 coincide with each other. Using.

[0012]

(Equation 3)

[0013]

(Equation 4)

Β ₁ (t): Time axis expansion / contraction coefficient of sound wave at receiver A5 and sound source at time t β ₂ (t): Time axis expansion / contraction of sound wave at receiver B6 and sound source at time t Coefficient The maximum correlation value between the reception waveforms of the receiver A5 and the receiver B6 is calculated by a plurality of Doppler correction devices that perform time compression or time expansion at a plurality of ratios predetermined in Expressions (3) and (4). Detected. That is, if the corrected received waveform is x ₁ ′ (t),

[0015]

(Equation 5)

Β (t): the time axis expansion and contraction coefficient of the sound wave between the receiver A5 and the sound source at the time t, the cross-correlation function Ri of x ₂ (t) and x ₁ ′ (t)
(Τ) is represented by the following equation.

[0017]

(Equation 6)

T: Received waveform measurement time When the integration time T is sufficiently long, Ri in the above equation (6)
(Τ) has no correlation with the noises n ₁ (βt) and n ₂ (βt), so that ββ ₁ ≒ β ₂ and the maximum value of the correlation at τ = D (t)

[0019]

(Equation 7)

Can be detected.

[0021]

However, the problem of the invention disclosed in Document 2 is that the traveling sound from the traveling body 4 traveling in the water 1 or the water surface 2 and the receiver A5 or the receiver The Doppler frequency generated between the reception waveforms received in B6 has a very wide range in the wideband noise targeted by the invention disclosed in Reference 2, and accurate correction cannot be performed even if a plurality of Doppler correction units are used. Because, Reference 3: Jack R
Williams: "A Nomogram for
VELOCITY AND RANGE DETERM
INATION FROM ACOUSTIC DOP
PLER ", INTERSTATE ELECTRONI
CS CORPORATION November Number 1
From 970, the relationship between the Doppler frequency and the sound source speed is represented by the following equation.

[0022]

(Equation 8)

Where f _D : Doppler frequency f ₀ : sound source frequency _VP : underwater sound propagation velocity V _W : radial water velocity of a circle centered on receiver A5 V _H : centered on receiver A5 circle radial receivers velocity V _t to: source Wataru Hashikarada rate from the formula (8), the Doppler frequency f _D is different it can be seen by means of the sound source frequency f ₀ and the sound source Kou Hashikarada velocity V _t and the like. The invention of Document 2 is based on the principle that a wide band frequency is used as the sound source frequency f ₀ . Therefore, by inputting the received waveform to a plurality of Doppler correction units having a plurality of predetermined time expansion / contraction ratios, a finite number of Doppler frequency components are removed to calculate a cross-correlation, and the maximum value thereof is calculated. Is to be detected. Therefore, according to the invention disclosed in Document 2, the infinite number of Doppler frequencies f _D generated in the broadband frequency sound source to be used are corrected by the finite number of Doppler correction units, and the Doppler-corrected reception waveform input to the cross-correlation unit There is a problem that the detection of the maximum value of the cross-correlation has a large error or cannot be detected.

According to the present invention, radiated noise caused by vibration characteristics determined by the shape and material of a hull or a propeller, such as a hull or a propeller, is included in the underwater noise of a marine vehicle traveling on or underwater. When the running speed increases or decreases, the known fact that the frequency band in the frequency spectrum does not change even if the noise source sound pressure increases and decreases and the verification fact according to the present invention are used. The present invention has newly invented a method for detecting radiation noise caused by characteristics from underwater radiation noise of a vehicle.

The present invention pays attention to these facts, and furthermore, based on the fact that the traveling speed of the sound source is obtained from the signal received by the receiver A based on the contents disclosed in Document 3, It is an object of the present invention to provide a navigation noise acoustic positioning device and method for performing Doppler correction for detecting the position of a navigation body by receiving navigation noise generated by a plurality of receivers.

[0026]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides: [1] two or more receivers for receiving radiation noise of a vehicle, and A receiver A (5) and a receiver B for detecting radiation noise of a vehicle in a positioning device that obtains a sound direction by taking a cross-correlation
(6) a receiving circuit (7, 8) for amplifying an input waveform signal to a certain level, an A / D converter (9, 10) for converting an analog waveform signal to a digital waveform signal,
An FFT processor (11, 12) for performing an FFT process on this digital waveform signal to convert it into a time-frequency signal, and a storage device (13, 1) for storing the FFT-processed time-frequency signal
4), a detector (15) for detecting a navigation noise frequency band caused by the running body vibration characteristics, and a bandpass filter for performing bandpass filtering in the navigation noise frequency band caused by the running body vibration characteristics. A processor (16, 17), a vehicle speed detector based on a Doppler frequency (18), and a Doppler correction calculation for performing a Doppler correction on the waveform signal subjected to the band-pass filter processing by obtaining a time expansion and contraction rate due to a Doppler phenomenon. Cross-correlation processing between the receiver (19) and the Doppler-corrected received signal, and from the maximum value, the difference between the arrival times of the traveling noise at the receiver A (5) and the receiver B (6) is detected. A correlation calculator (20); and a display (21) for calculating and displaying the direction and position of the target vehicle based on the result of the cross-correlation calculation. Corrects the effect of the Doppler effect that occurs between the received signals received by the receiver, enables the calculation of the maximum value of the cross-correlation between each received signal, and enables the The arrival time difference is detected, and the position of the sound source is specified.

[2] In particular, in the navigation noise acoustic positioning device for performing the Doppler correction according to the above [1], the detector (15) for detecting a navigation noise frequency band caused by the vibration characteristics of the navigation body includes: And (a) reading the time-frequency received signal subjected to the FFT processing from the storage device (13, 14) based on the received signal from the first receiver, and forming a loafergram every sampling time N seconds. Means to create,
(B) A frequency of 0 to FHz in the loafgram
Means for extracting a power value maximal value sequence in a spectrum line between the two, and (c) performing the processing of the means (a) and (b) on the loafgram in the range of the power value of the traveling noise in the frequency range of 0 to FHz. And (d) performing the processing by means (a), (b) and (c) based on the signal received by the second receiver, The upper limit value and the lower limit value of the navigation noise frequency band detected based on the first receiver received signal are determined based on the navigation noise frequency band detected based on the second receiver received signal. Means for determining, when the upper limit value and the lower limit value coincide with each other, a frequency band of the running noise caused by the running body vibration characteristics.

[0028] Further, in the acoustic positioning method for running noise that performs Doppler correction according to the present invention, [6] the radiation noise of the running vehicle is received by two or more receivers, and In the positioning method for determining the direction of the sound by taking the cross-correlation of the vehicle, the navigation noise generated by the vehicle is determined based on the determination of the traveling speed of the sound source from the signal received by the first receiver. Is received by multiple receivers, and when the sound source travels at high speed, the effect of the Doppler effect that occurs between the received signals received by two or more receivers is corrected, and the The maximum value of the cross-correlation can be calculated, the difference in the arrival time of the vehicle radiation noise to each receiver is detected, and the position of the sound source is specified.

[7] In particular, in the acoustic positioning method for running noise for performing Doppler correction according to the above [6], (a) F is stored in the storage device based on a signal received by the first receiver.
The time-frequency reception signal subjected to the FT processing is read, and a loafgram is generated every sampling time N seconds,
(B) a frequency of 0 to FHz in the loafgram
(C) applying the processing of (a) and (b) to the maximum value sequence of the power values of the running noise in the frequency range of 0 to FHz in the lophergram; For all of the groups,
(D) The processes (a), (b) and (c) are performed based on the second receiver signal, and the upper limit and the lower limit of the running noise frequency band detected therefrom are set to the first value. When the upper and lower limits of the frequency band of the signal received by the receiver are matched with each other, the frequency band of the traveling noise caused by the vibration characteristics of the vehicle is used to perform Doppler correction. It was made.

The speed of the sound source vehicle will be described in more detail below. Within the frequency band of various noises caused by vibration characteristics determined by the shape and material of the vehicle such as a hull or a propeller, the present invention described above. From the verification facts and the known facts of the prior art, when the Doppler phenomenon is considered, using the noise in the low frequency band below FHz as the sound source frequency, it can be obtained from the principle described below.

According to the technique disclosed in Document 3, the receiver A
5 or the sound wave received by the receiver B6, the following equation (9) holds.

[0032]

(Equation 9)

Where f _D = Doppler frequency f ₂ = upper limit Doppler frequency f ₁ = lower limit Doppler frequency The above equation (9) also shows the radial water velocity V _{W of} a circle centered on the receiver and the received wave the radial source Kou Hashikarada velocity V _H of a circle centered on the vessel, as both receivers is at rest, when V _W = V _H = 0, the equation (9),

[0034]

(Equation 10)

Here, since V _p ≫V _t generally,

[0036]

[Equation 11]

From equations (10) and (11),

[0038]

(Equation 12)

Is derived, where (f ₂ −f ₁ ) 0f ₀
Substituting the underwater sound wave propagation velocity V _P = 1500 m / s into equation (10) gives

[0040]

(Equation 13)

From equation (8),

[0042]

[Equation 14]

Here, V _r : velocity of the sound source vehicle in the radial direction of the circle centered on the receiver from the equation (14)

[0044]

(Equation 15)

If the Doppler frequency and the sound source frequency are known from the above equation (15), the speed of the vehicle can be detected.

The azimuth measurement of the sound source vehicle from the receivers A5 and B6 is based on the following principle.

The received waveform received by the receiver A5 is represented by x
₁ (t), the received waveform received by the receiver B6 is x ₂ (t)
And Assuming that s (t) is an amplitude obtained by removing noise and the Doppler effect from the reception waveform of the receiver A5 at the time t, the reception waveforms x ₁ (t) and x at the receivers A5 and B6 are obtained.
₂ (t) is expressed by the following equation including the Doppler effect.

[0048]

(Equation 16)

[0049]

[Equation 17]

Here, β ₁ (t): Reception receiver A5 and target reception waveform time axis expansion / contraction coefficient at time t β ₂ (t): Receiver B6 and target reception waveform time axis at time t Expansion / contraction coefficient D (t): difference in arrival waveform arrival time between receivers A5 and B6 at time t n ₁ (t): Gaussian white noise received by receiver A5 at time t n ₂ (t): time t The Gaussian white noises n ₁ (t) and n ₂ (t) received by the receiver B6 are uncorrelated.

Here, the Doppler frequency of the receiver B6 is corrected in order to match the frequencies of the reception waveforms of the receiver A5 and the receiver B6.

Assuming that the corrected signal waveform is x ₂ ′ (t)

[0053]

(Equation 18)

Where β = β ₁ / β ₂ , the cross-correlation function R of x ₁ (t) and x ₂ ′ (t)
(Τ) is represented by the following equation.

[0055]

[Equation 19]

Here, α (t) is a signal attenuation coefficient at time t.

The second term in the above equation (19) is n ₁ (t) and n
It is 0 because ₂ (t) is uncorrelated.

The first term is that at τ = −β ₁ D

[0059]

(Equation 20)

Therefore, the cross-correlation becomes maximum at R _S.

As can be seen from the above equation (20), the correlation becomes maximum at τ = −β ₁ D by expanding and contracting the time axis of the received waveform x ₂ (t) by β times and performing Doppler correction. However, even if β (β ₁ / β ₂ ) that maximizes the correlation is obtained, the values of β ₁ and β ₂ cannot be obtained, and the position of the maximum value is β ₁
A double-shifted error remains. The above is described with a sine wave.

[0062] In FIG. 3, V ₁ the velocity component of the velocity of the domestic Hashikarada the wave receiver A and V _r, the velocity component of the receivers B V
_2, when the frequency of the radiation noise of the target domestic Hashikarada and f _0, a frequency f _A which is received by the wave receiver A, the frequency f _B received by the wave receiver B are each represented in the following equation.

[0063]

(Equation 21)

[0064]

(Equation 22)

Where β ₁ = 1−V ₁ / V _P β ₂ =
According to 1−V ₂ / V _P , the input received waveform is

[0066]

(Equation 23)

[0067]

(Equation 24)

[0086] Then, the following is set. Further, when the reception waveform of the receiver B is made to coincide with the reception waveform of the receiver A by Doppler correction, x ₂ ′ (t) in FIG. 3 is obtained.

Accordingly, the two received waveforms x ₁ (t) and x ₂ ′ (t) after Doppler correction in FIG. 3 are represented by the following equations.

[0070]

(Equation 25)

[0071]

(Equation 26)

Thus, the cross-correlation function R (τ) between x ₁ (t) and x ₂ ′ (t) is

[0073]

[Equation 27]

If the maximum value of the cross-correlation between the two acoustic waveforms x ₁ (t) and x ₂ ′ (t) is detected by the above equation (27) by the above Doppler correction, the two noises of the target vehicle radiation noise can be detected. The arrival time difference τ ₀ between the wave device A and the wave receiver B can be detected.

That is, the above equation (21) and the above equation (2)
The value according to 2) is input to the cross-correlation calculator 20 in FIG. 1 and processed. The cross-correlation calculator 20 calculates the cross-correlation as shown in FIG.

FIG. 4 shows the principle of obtaining the direction of arrival. The signals from the receiver A and the receiver B are noises generated from the same sound source. If the signals are sufficiently far from the vehicle 4, the signals input to the receivers A and B are parallel waves. Can be considered. Here, when the time when the same wave is received by the receiver A and the receiver B is known, the distance r corresponding to the arrival time difference is obtained from the arrival time difference. If the distance between receiver A and receiver B is d

[0077]

[Equation 28]

Since the above expression holds, the arrival direction of the sound wave can be obtained from the above equation (28).

The above description has been made of the case where there are two receivers. However, as shown in FIG. 5, a plurality of receivers are installed in water, and the azimuth θ ₁ is obtained, and θ ₂ is obtained by the receiver C and the receiver D. From this, a straight line is drawn at the azimuth angles θ ₁ and θ ₂ from the positions of the respective receivers, and the intersection point is set to P ₀ , whereby the position of the target marine vehicle can be specified.

The principle described above can also be realized for a positioning device using a Pinger system or a transponder system using a predetermined frequency.

[0081]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the apparatus for performing Doppler correction of the running noise and measuring the position of the target running body according to the present invention.

In this figure, 1 is underwater, 2 is water surface, 3
Is the sea floor, 4 is the carrier, 5 is receiver A, 6 is receiver B, 7
And 8 are receiving circuits, 9 and 10 are A / D converters, 11 and 12
Is an FFT processor, 13 and 14 are storage devices, 15 is a navigation noise frequency band detector due to the vibration characteristics of the vehicle, 16 and 17 are bandpass filter processors, 18 is a vehicle speed detection based on Doppler frequency. , 19 is a Doppler correction calculator, 20 is a cross-correlation calculator, and 21 is a display.

The receiver A5 and the receiver B6 detect the traveling sound of a traveling body traveling on the water surface or underwater, and are, for example, hydrophones.

The receiving circuits 7 and 8 are provided with a receiver A5 and a receiver B
After amplifying the waveform signal input from 6 to a certain level, the signal is output to A / D converters 9 and 10.

A / D converters 9 and 10 are provided with receiving circuits 7 and 8
From the analog waveform signal transferred from the FFT processors 11 and 12
Transfer to

FIG. 6 is a diagram showing an example of a navigation noise reception signal detected by the receiver A, the receiver B, and the receiver C.
(A) is a received signal of the traveling noise by the receiver A, and FIG.
6A shows the received signal of the traveling noise by the receiver B, and FIG. 6C shows the received signal of the traveling noise by the receiver C. The vertical axis represents amplitude, and the horizontal axis represents measurement time.

The FFT processors 11 and 12 perform FFT processing on the digital waveform signal every N seconds, convert the digital waveform signal into a time-frequency signal, and transfer it to the storage devices 13 and 14.

FIG. 7 is a diagram showing an example of the frequency spectrum of the traveling noise detected by the receiver A, the receiver B, and the receiver C. FIG. 7 (b) shows the running noise frequency spectrum of the receiver B, and FIG. 7 (c) shows the running noise frequency spectrum of the receiver C. In FIG. It is an example of a running noise frequency band caused by body vibration characteristics. Here, the vertical axis is the power value, and the horizontal axis is the frequency.

The traveling noise frequency band detector 15 caused by the vibration characteristics of the traveling vehicle fetches the waveform signals converted into the time-frequency signals from the storage devices 13 and 14 into the detectors individually, and receives the signals. creating a loafer grams per sampling time N seconds for A5 each received waveform x ₁ (t) and the received waveform x ₂ of receivers B6 (t) of the. The value on the vertical axis of one spectrum line in the loafgram is the power value, and the horizontal axis is the frequency. That is, the frequency spectrum shown in FIG. 7 is arranged as T / N lines every N seconds as one spectrum line, which is the lofergram. Here, a running noise frequency band caused by the running body vibration characteristics is detected based on the loafgram.

A method of detecting the running noise frequency band will be described below.

The running noise due to the running body vibration characteristics has the following characteristics based on the known facts and the verification facts of the present invention. (1) Even if the traveling speed changes, the frequency band of the noise does not change. (2) When vibration from a vibration source fixed to the hull, such as an engine or a generator, propagates through the hull and is radiated into water, the underwater radiation noise has a natural frequency band synchronized with the vibration characteristics of the hull. . (3) The running noise having a low frequency of FHz or less is a continuous wave having a large power value and propagates far.

Therefore, the detection of the traveling noise having the Doppler phenomenon having the above characteristics is performed in the following procedure.

The FFT-processed time-frequency reception signal is read from the storage device, and a loafgram is generated every sampling time N seconds.

In the loafgram, the frequency 0
A sequence of power value maxima in a spectrum line between FHz is extracted. The extraction conditions are as follows.

I. (C-1) in the frequency range of 0 to FHz
There must be a local maximum in any of the th, cth, and (c + 1) th spectral lines. That is, the characteristics of (1), (2), and (3) above are satisfied within the running noise,
In addition, the presence or absence of a frequency where the Doppler phenomenon occurs is observed.

Ii. The difference between the maximum frequencies of adjacent spectral lines is the incremental upper limit value σf (here, for example, when df is frequency resolution, df <σf
<3df). That is, (1),
It is checked whether the frequency satisfies the characteristics of (2) and (3) and belongs to the frequency causing the Doppler phenomenon.

Iii. If the increment upper limit value σf of ii is exceeded, the processing shifts to the next spectral line as data loss.

Iv. A maximum value sequence of the next spectrum line satisfying the conditions i and ii is detected in a frequency range exceeding the increment upper limit value σf representing a frequency shift.

The above-described processing is performed on all the maximal value sequence groups of the power values of the traveling noise in the frequency range of 0 to FHz in the lofergram.

The above processing procedure is similarly performed on the received signal x ₂ (t) by the receiver B, and the upper limit value and the lower limit value of the navigation noise frequency band detected there are determined by the receiver A. In the case where the upper limit value and the lower limit value of the frequency band of the received signal x ₁ (t) coincide with each other, the frequency band is determined as the frequency band of the traveling noise caused by the vibration characteristics of the traveling body.

FIG. 8 is a diagram showing an example of a loafgram with a sampling time of N seconds for the received signal of the traveling noise, in which the vertical axis indicates the frequency and the horizontal axis indicates the measurement time.

In FIG. 8, a time-frequency signal of the traveling noise, in which the power value on the frequency spectrum line every N seconds forms a maximum value sequence by the traveling noise frequency band detector 15 caused by the traveling body vibration characteristics, and The detection example of the upper limit value and the lower limit value of the running noise frequency range caused by the running body vibration characteristic is shown.

The running noise frequency band detector 15 inputs the detected upper limit value and lower limit value of the running noise frequency band to the band-pass filter processor, and outputs the power on the frequency spectrum line every N seconds. The time-frequency waveform signal having the maximum value sequence is transferred to the vehicle speed detector 18 based on the Doppler frequency.

The bandpass filter processors 16 and 17 perform bandpass filtering on the waveform signals stored in the storage devices 13 and 14 within the range of the upper limit value and the lower limit value of the frequency band input from the running noise frequency band detector 15. Filter processing is performed and the result is transferred to the Doppler correction calculator 19.

FIG. 9 shows receivers A, B, and C that have been subjected to band-pass filter processing in the range of the upper limit value and the lower limit value of the running noise frequency band caused by the running body vibration characteristics.
1 shows an example of a signal waveform according to FIG.

The traveling vehicle speed detector 18 based on the Doppler frequency calculates the time-frequency at which the power value on the frequency spectrum line every N seconds transferred from the traveling noise frequency band detector 15 forms a maximum value sequence in the lofergram. From the waveform signal, the above equation (15) and Reference 4: Japanese Patent Application No. 10-190
In No. 212, the Doppler frequency is obtained by the technique proposed by the present inventors, and the speed of the vehicle is detected. Then, the value of the detected traveling vehicle speed is input to the Doppler correction calculator 19.

FIG. 10 is a diagram showing an example of detection results of the upper limit Doppler frequency f ₂ and the lower limit Doppler frequency f ₁ by the vehicle speed detector 18 based on the Doppler frequency.
The vertical axis indicates frequency, and the horizontal axis indicates time.

The Doppler correction operation unit 19 performs the Doppler correction on the waveform signals input from the band-pass filter processors 16 and 17 by obtaining the time expansion and contraction rate of the received waveform due to the Doppler phenomenon from the above equation (27). For β ₁ , the Doppler correction is performed by substituting the sailing body speed V _r input from the sailing body speed detector 18 based on the Doppler frequency into the above equations (21) and (22). It should be noted that, when the speed of the target cruising vehicle is detected in advance by another measuring means, the target cruising speed detected by the other measuring means is not used by the traveling vehicle speed detector 18 based on the Doppler frequency. The present invention can also be implemented by inputting the body velocity to the Doppler correction calculator 19.

In the cross-correlation calculator 20, the received waveforms x ₁ (t) and x
_{For 2} ′ (t), the maximum value of the cross-correlation function is calculated from the above equation (27), and the arrival time difference at that time is obtained.

FIG. 11 shows the result of the cross-correlation calculator 20 calculating the arrival time difference between the receivers for the waveform signals received by the receivers A, B and C.

The present invention is not limited to the above embodiments, but various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0113]

As described above, according to the present invention, the radiation noise of a vehicle is received by two or more receivers, and the cross-correlation between the received signals is obtained, whereby the azimuth of the sound source is obtained. The cross-correlation error caused by the effect of the Doppler effect due to the navigation of the sound source on the waveform signal of the receiver is determined by the navigation noise frequency band detector caused by the vehicle's vibration characteristics, and the Doppler frequency Detects the position of the target vehicle by compensating with the vehicle speed detector and the Doppler corrector, and easily detecting the difference in the arrival time of the vehicle radiation noise to each receiver by cross-correlation. You can do it.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a vehicle positioning apparatus for performing Doppler correction from running noise according to the present invention.

FIG. 2 is a configuration diagram of an example of a conventional technique disclosed in Document 1.

FIG. 3 is an explanatory diagram showing a relationship between a sound source speed and occurrence of a Doppler frequency difference.

FIG. 4 is a diagram illustrating the principle of detecting the direction of a target sound source.

FIG. 5 is an explanatory diagram of a positioning principle of a target sound source by a plurality of receivers.

FIG. 6 is a diagram showing an example of a traveling noise reception signal detected by the receiver A, the receiver B, and the receiver C.

FIG. 7 is a diagram illustrating an example of a frequency spectrum of navigation noise detected by the receiver A, the receiver B, and the receiver C. Σ is an example of the running noise frequency band caused by the running body vibration characteristics.

FIG. 8 is a diagram showing an example of a loafgram every N seconds for a sampling time of a running noise reception waveform.

FIG. 9 is a diagram showing an example of waveform signals from the receiver A and the receiver B that have been subjected to bandpass filter processing in the range of the upper limit value and the lower limit value of the running noise frequency band caused by the vibration characteristics of the vehicle. It is.

10 is a diagram showing an example of detection of the upper limit Doppler frequency f ₁ and the lower limit Doppler frequency f ₂ by due to the Doppler frequency Kou Hashikarada speed detector.

FIG. 11 shows a receiver A, a receiver B,
It is a figure which shows an example which calculated | required the arrival time difference between each receiver about the reception waveform measured by the receiver C.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Underwater 2 Water surface 3 Sea bottom 4 Aircraft 5 Receiver A 6 Receiver B 7,8 Receiving circuit 9,10 A / D converter 11,12 FFT processor 13,14 Storage device 15 Vehicle vibration characteristics Navigation noise frequency band detector due to noise 16, 17 Band-pass filter processor 18 Vessel velocity detector based on Doppler frequency 19 Doppler correction calculator 20 Cross-correlation calculator 21 Display

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01S 7/526 G01S 7/52 J (72) Inventor Hideyuki Takahashi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. F term (reference) 5J083 AA05 AC07 AD01 AD08 AD17 AE02 BE06 BE10 BE12 BE43 BE44 BE54 CA07 DA01 EB02

Claims (7)

[Claims] 1. A positioning apparatus for receiving a radiation noise of a traveling vehicle by two or more receivers and calculating a cross-correlation between the received signals to determine an azimuth of sound. A (5) and B (6) for detecting radiation noise of
Receiving circuits (7, 8) for amplifying an input waveform signal to a certain level; A / D converters (9, 10) for converting an analog waveform signal into a digital waveform signal; An FFT processor (11, 12) for performing FFT processing and converting it into a time-frequency signal, and a storage device (13, 14) for storing the FFT-processed time-frequency signal;
A detector (15) for detecting a running noise frequency band caused by the running body vibration characteristics, and a bandpass filter processor (16) for performing bandpass filtering in the running noise frequency band caused by the running vehicle vibration characteristics. , 17), a vehicle speed detector based on the Doppler frequency (18), and a Doppler correction calculator (19) for performing Doppler correction by obtaining the time expansion and contraction ratio of the waveform signal subjected to the band pass filter processing due to the Doppler phenomenon. And a cross-correlation calculator that performs cross-correlation processing on the Doppler-corrected received signal and detects a difference in arrival time of the traveling noise between the receiver A (5) and the receiver B (6) from the maximum value. 20) and an indicator (21) for calculating and displaying the direction and position of the target hull based on the result of the cross-correlation calculation. When the sound source cruises at high speed,
By correcting the effect of the Doppler effect that occurs between the received signals received by two or more receivers, it is possible to calculate the maximum value of the cross-correlation between the received signals, and to obtain the reception of the vehicle radiation noise. An acoustic positioning device for running noise that performs Doppler correction by detecting a difference in arrival time to a wave device and specifying a position of a sound source. 2. A navigation noise acoustic positioning apparatus for performing Doppler correction according to claim 1, wherein the detector detects a navigation noise frequency band caused by the vibration characteristics of the navigation body.
Is (a) the time when the FFT processing is performed from the storage device (13, 14) based on the signal received by the first receiver;
Means for reading the received frequency signal and creating a loafgram every N seconds of sampling time; and (b) means for extracting a power value maximal value sequence in a spectrum line between frequencies 0 and FHz in the loafgram.
(C) means for performing the processing of the means (a) and (b) for all of the maximum value sequence groups of the power values of the running noise in the range of frequencies 0 to FHz in the lofergram; A) performing the processing by the means (a), (b) and (c) based on the signal received by the second receiver and detecting the navigation detected based on the signal received by the first receiver; When the upper limit value and the lower limit value of the running noise frequency band match the upper limit value and the lower limit value of the running noise frequency band detected based on the second receiver received signal, Means for determining the frequency band of the running noise caused by the characteristic. Acoustic positioning apparatus for the running noise that performs Doppler correction. 3. The acoustic positioning device for running noise which performs Doppler correction according to claim 1, wherein the means for detecting the speed of the vehicle based on the Doppler frequency is other than a means for detecting the speed.
When the target vehicle speed is detected, the value of the target vehicle speed by the other means is sent to the Doppler correction calculator (19) instead of the vehicle speed detector (18) based on the Doppler frequency. By inputting, it is possible to calculate the maximum value of the cross-correlation between each received signal, detect the difference in the arrival time of the vehicle radiation noise to each receiver, and specify the position of the sound source Acoustic noise positioning system that performs Doppler correction. 4. A plurality of acoustic positioning devices for running noise for performing Doppler correction according to claim 1, which are installed in a horizontal direction, and their intersections are determined from the directions of the sound sources determined by the respective devices, and a sound source position is specified. An acoustic positioning device for running noise that performs Doppler correction characterized by the following. 5. A plurality of acoustic positioning devices for running noise for performing Doppler correction according to claim 1, which are installed in a vertical direction, and their intersections are determined from the directions of the sound sources determined by the respective devices to specify the position of the sound source. An acoustic positioning device for running noise that performs Doppler correction characterized by the following. 6. A positioning method for receiving an radiated noise of a vehicle by two or more receivers and calculating a cross-correlation between the received received signals to determine an azimuth of sound. Based on the fact that the traveling speed of the sound source is obtained from the signal received by the receiver, the traveling noise generated by the vehicle is received by multiple receivers, and when the sound source travels at high speed Correcting the effect of the Doppler effect occurring between the received signals received by two or more receivers, enabling the calculation of the maximum value of the cross-correlation between the received signals, and An acoustic positioning method for running noise that performs Doppler correction by detecting a difference in arrival time to a receiver and specifying a position of a sound source. 7. The acoustic positioning method for running noise for performing Doppler correction according to claim 6, wherein (a) a time-frequency signal subjected to FFT processing from a storage device based on a signal received by the first receiver. The received signal is read to create a loagram every N seconds of the sampling time, and (b) a maximum value sequence of power values in a spectrum line between frequencies 0 to FHz is extracted from the loagram, and (c) the (a) ) And (b) are carried out for all of the maximal value sequence groups of the power values of the running noise in the range of 0 to FHz in the lofergram, and (d) the above (a),
The processing of (b) and (c) is performed based on the received signal of the second receiver, and the upper limit value and the lower limit value of the running noise frequency band detected there are determined by the received signal of the first receiver. A running noise acoustic positioning method for performing Doppler correction, characterized in that when the upper limit value and the lower limit value of the frequency band coincide with each other, the frequency band of the running noise caused by the running body vibration characteristics is used.