JP2647041B2 - Passive sonar signal processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive sonar signal processing system.

[0002]

2. Description of the Related Art Various types of passive sonars are known. For example, a towed passive sonar (TASS) for towing a receiver away from its own ship has a linear shape as shown in FIG. A wave receiving array 1 as the wave receiver in which the wave receiving elements are arranged, a wave phasing device 2 for phasing the wave signals output from these wave receiving element groups to form a beam, and The apparatus includes a signal processor 3 for performing narrow-band processing on a signal and a display 4 for displaying a spectrum of the narrow-band processed signal.

[0003] This TASS has such advantages that disturbance of own ship noise is reduced and azimuth resolution can be largely improved by a long receiving array. Specifically, since a beam having directivity can be formed even in a frequency range of 500 Hz or less from the array length, a narrow band analysis of a line spectrum component having a large SN ratio in a low frequency range of 500 Hz or less in the target transmission sound is performed. It can be detected by processing and enables long-distance target search.

A hull sonar (HULL sonar) mounted on the bottom of a surface ship can perform not only an active operation but also a passive operation.
As shown in FIG. 5, a wave transmitter / receiver 5b, a phase adjuster 6 for phasing a received signal output from the wave transmitter / receiver 5b to form a beam,
A signal processor 7 for performing an integration process on the phase-adjusted signal, and a display device 8 for performing an interpolation process on the signal subjected to the integration process and displaying the result on a display of a horizontal axis direction and a vertical axis time.

[0005] In this conventional HULL sonar, since the transducer 5b mounted in the sonar dome at the bottom of the ship is cylindrical, it is difficult to form a beam having directivity by using 50 mm.
Since the frequency range is 0 Hz or more, in the signal processing at the time of the passive operation, the detection of the line spectrum having a large SN ratio cannot be expected, and the wideband processing of detecting the noise level in the wideband is employed.

Therefore, conventionally, when searching for a submarine from a surface ship, the HULL sonar performs a passive operation, and at the same time, performs a long-distance search by TASS, and performs a target search based on the line spectrum displayed on the display 4. Once the submarine has been detected, the target location is limited by TMA (Target Motion Analysis) provided by TASS. Since the result is displayed on the display 4, if the target submarine is assumed to be at a long distance, an anti-submarine helicopter deployed on the surface ship is launched to track the target and limit the position. If it is assumed that the target submarine is in a short distance, it is necessary to carry out quick localization, so the HULL sonar performs an active operation, emits sound waves underwater, receives reverberations from the target, The azimuth and distance are measured.

[0007]

As described above, conventionally, when searching for a submarine on a surface ship, a TASS and a HULL sonar are used in combination, but both are separated as independent devices and are not related to each other. It is used. Therefore, when the submarine is improved in performance due to silence, improvement of attack power, and the like, the following problem occurs.

First, there is a problem that it takes time to limit the location by TMA. That is, since the TASS receivers are linearly arranged, the reception beam having a cross section perpendicular to the towing direction has an omnidirectional shape, and whether the target is detected is left or right in the towing direction. Is unknown. In order to eliminate this, the surface ship must change course and sail, re-detect the target, and determine whether the true target is in the left or right direction.

[0009] Therefore, for submarines that are at risk of torpedo attack, HUL instead of TMA, which requires time for localization, is used.
The problem can be solved if the location limitation can be achieved by the cross-fix of the L sonar and TASS measurement directions.
Currently, the LL sonar is not able to provide the passive search capabilities that enable it.

[0010] In addition, the HULL sonar detects the submarine first by the passive operation of the HULL sonar because the capacity at the time of the passive operation, that is, the maximum detection distance becomes significantly shorter than that at the time of the active operation when the submarine becomes quiet. There is also a problem that it is difficult to take an action to shift to the active operation, and the significance of the passive operation of the HULL sonar is lost.

It is an object of the present invention to provide a passive sonar signal processing method capable of effectively detecting a submarine having such a high performance and quickly performing position limitation.

[0012]

In order to achieve the above object, a passive sonar signal processing system according to the present invention has the following configuration. That is, the passive sonar signal processing method according to the first invention is a receiving array in which receiving elements are linearly arranged, and a phasing of receiving signals output from a receiving element group to form a beam. A towed passive sonar (TASS) comprising a device, a signal processor for narrow-band processing the phased signal, and an indicator for spectrally displaying the narrow-band processed signal;
A wave receiving array in which receiver elements are arranged in a plane, a phase adjuster for phasing a received signal output from a receiver element group to form a beam, and a signal processing for integrating an input signal. Hull bottom sonar (hull sonar) equipped with a display and an interpolator for interpolating the integrated signal and displaying it on the display of the horizontal axis direction and the vertical axis time; A selection circuit for selecting a signal of only a designated channel from the following; a correlation operation circuit for performing a correlation operation between the selected signal and an output signal of a hull sonar phaser;
A signal switching circuit that switches between an output signal of the correlation operation circuit and an output signal of the hull sonar phaser in response to an integration switching command and supplies the output signal to the hull sonar signal processor.

A passive sonar signal processing method according to a second aspect of the present invention is a method for converting a plurality of beams formed by phasing a received signal output from a group of linearly arranged receiver elements into a radio signal and transmitting the converted signal. A sonobuoy signal processing device comprising: a sound buoy; a receiver for receiving and processing radio signals from a plurality of sound buoys; a signal processor for narrow-band processing the output of the receiver; and a display for spectrally displaying the narrow-band processed signal. A hull sonar according to the first invention; a selection circuit for selecting a specified reception signal from reception signals for each acoustic sonobuoy output by a receiver of the sonobuoy signal processing device; and a selected signal and a hull sonar phaser A correlation operation circuit for performing a correlation operation with the output signal of the Halso; switching between the output signal of the correlation operation circuit and the output signal of the hull sonar phaser in response to a single / integral switching command Characterized by comprising a; and a signal switching circuit for applying to the toner of the signal processor.

A passive sonar signal processing method according to a third aspect of the present invention includes a plurality of acoustic buoys according to the second aspect of the present invention; a receiver for receiving and processing radio signals of the plurality of acoustic buoys; A selection circuit for selecting signals related to the two acoustic buoys; a correlation operation circuit for performing a correlation operation on the selected signals relating to the two acoustic buoys; a signal processing circuit for performing an integration process on the signals subjected to the correlation operation; And a display that displays the signal in the horizontal axis direction and the vertical axis time.

[0015]

Next, the operation of the passive sonar signal processing system of the present invention configured as described above will be described. In the first invention and the second invention, when the target detection is displayed on the display of the TASS (first invention) or on the display of the signal processing device (second invention), the phasing signal and the passive signal are displayed. The correlation with the hull sonar phasing signal is performed, and the result is given to a hull sonar signal processor, integrated, and displayed.

Accordingly, the processing gain is improved as compared with the hull sonar alone in the passive operation.
Alternatively, the hull sonar can be expected to detect the target in passive operation following the detection by multiple acoustic buoys, so that the target localization is shortened due to the difference in occupancy of TASS or the installation position of the receiving array of multiple sonobuoys and hull sonars. It can be realized in time, and the oversight of the transition time of Halsoner to active operation can be reduced.

In the third aspect of the present invention, the correlation processing is performed between two acoustic buoys selected from the plurality of acoustic buoys in the second aspect of the present invention. Location restrictions can be performed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a passive sonar signal processing method according to a first embodiment of the present invention. In FIG. 1, a signal processing method according to the first embodiment includes a TASS 15 and a HULL sonar 1.
6, a selection circuit 9, a correlation calculation circuit 10, and a signal switching circuit 11 are provided to connect the two devices, which were conventionally independent devices, so that time is limited to a position limited to a submarine that may be subjected to a torpedo attack. Instead of the required TMA, the location limitation can be achieved by the cross-fix of each measurement direction of the HULL sonar and the TASS.

The TASS 15 has the same configuration as that shown in FIG. The output of the phase adjuster 2 of this TASS 15 is
It is also provided to the selection circuit 9. The selection circuit 9 selects a phasing output signal of a designated azimuth in accordance with a detection azimuth signal given from the outside, and supplies it to one input of a correlation operation circuit 10. The detection azimuth is input by the operator looking at the line spectrum displayed on the display 4.

On the other hand, the HULL sonar 16 can perform both active and passive operations as in the prior art, but in the present invention, unlike the one shown in FIG.
The transmitter / receiver is composed of a transmitter (not shown) and a receiver (receiver array 5).
a), the wave receiving array 5a is mounted on both sides of the surface ship as a large-sized surface array corresponding to a lower frequency. This wave receiving array 5a (plane array) has a total length of 10
m or more, a beam having directivity can be formed even at a frequency of 500 Hz or less at the time of passive operation, and a line spectrum of the target transmission sound having a relatively large SN ratio can be detected. Further, a phase adjuster 6 and a signal processor 7
There is no direct connection between them, and the output of the phase adjuster 6 is
0 and one input of the signal switching circuit 11, and the input of the signal processor 7 is connected to the signal switching circuit 1
Given from 1.

The signal switching circuit 11 receives the other input from the correlation operation circuit 10 in response to an external / integral switching command given from the outside, that is, in the case of a single operation, outputs the output of the phase adjuster 6 to a signal processor. 7, the correlation operation circuit 1 in the case of integration
The output of 0 is given to the signal processor 7. This switching command is determined by the operator by looking at the display 4 and the display 8 and input.

The case where the passive sonar signal processing of the present invention, that is, the correlation operation is performed, will be described below with reference to FIGS. In FIG. 2, a TASS receiving array 1
Receives the noise n _T (t) and the radiation sound S (t) of the submarine 13. On the other hand, HUL with surface ship 12
The wave receiving array 5a of the L sonar receives the noise n _T (t) and the radiation sound A · S (t−τ) of the submarine 13. A is a level difference from the TASS received sound based on the sound wave propagation loss, and τ is a time difference from the TASS received sound based on the relative position to the target.

When the HULL sonar and the TASS receive the radiation sound of the submarine 13 under the situation as shown in FIG.
Target ship radiation sound S (t) and noise n received by ASS
_T (t), the noise n _H (t) received by the HULL sonar is
Each is a "stationary ergote random process with an expected value of 0" and "all are uncorrelated with each other"
It is thought that it has the characteristic of.

Target ship radiation sound S (t) received by TASS
Is a relational expression in which the correlation operation is performed assuming that the interval exists between the sections [t−τ, t]. The SN relationship between the input and output of such a correlation calculation process is obtained as in Expression 2. However, in Equation 2, S ₀ is the output signal, N ₀ ² The output noise power, W is the signal bandwidth, S is the power of the TASS received signal, N is the TASS, a power of NULL sonar receiver noise.

[0025]

(Equation 1)

[0026]

(Equation 2)

Equation (2) can be expressed as (S
/ N) << 1 is approximated as in Equation 3, and (S /
N) >> 1 is approximated as in Expression 4.

[0028]

(Equation 3)

[0029]

(Equation 4)

Here, assuming that the power of the received signal of the HULL sonar is S _H , A ² S = S _H.
Is rewritten as Equation 5, and Equation 4 is rewritten as Equation 6.

[0031]

(Equation 5)

[0032]

(Equation 6)

From the above, the processing gain PG is (S /
N) << 1 is represented by Expression 7, and (S / N) >> 1
Is represented by Expression 8.

[0034]

(Equation 7)

[0035]

(Equation 8)

On the other hand, the wave receiving array 5a of the HULL sonar
Surface ship 1 than the distance between the satellite and the TASS receiving array 1
Since the distance between the submarine 2 and the submarine 13 is sufficiently long, A ≒ 1 can be set. Therefore, when (S / N) << 1, Equation 7 is simplified to Equation 9, and (S / N) ) >> In the case of 1, Expression 8 becomes a simple expression as Expression 10.

[0037]

(S / N) << When 1: PG = 5log 2WT

[0038]

(S / N) >> 1: PG = 10 log WT

Now, as shown in FIG. 3, the radiation noise characteristic of the target submarine to which the present invention is directed has a plurality of line spectra in the frequency range of 500 Hz or less, and its SN.
It is assumed that the ratio is (S / N) >> 1. Then, when the correlation processing is performed, the processing gain of Expression 10 can be expected.

On the other hand, the HULL sonar wave receiving array 5a
Since the total length is 10 m or more, a beam having directivity up to the low frequency region where the above-mentioned line spectrum exists can be formed by the phase adjuster 6, and the integrated processing of the passive sonar signal of the present invention becomes possible. For example, if there are 10 line spectra with a bandwidth of 0.5 Hz, the processing gain of the present invention is such that the signal bandwidth W = 0.5 × 10 = 5 Hz,
When the integration time T = 30 seconds, PG = 21.
8 dB.

HUL using such a wave receiving array 5a
Even if the L sonar is used alone and the same broadband processing as that of the conventional HULL sonar is performed, the line spectrum disappears due to the integration process, and it is difficult to detect the target. But TA
By correlating the phasing output of the direction detected by the SS with the phasing output of the HULL sonar at the time of passive operation, the processing gain of the line spectrum can be improved.
Thereafter, even if the signal processor 7 performs an integration process, the target can be detected. Further, since the HULL sonar can display the BT in the horizontal axis direction and the vertical axis time in the same manner as in the related art, the accuracy of the target direction is improved and the movement of the target can be accurately grasped.

Next, FIG. 4 shows a passive sonar signal processing system according to a second embodiment of the present invention. In the second embodiment, the function of TASS in the first embodiment is assigned to a plurality of sound buoys 41 and a sonobuoy signal processing device 42, and the same operation and effect as those of the first embodiment can be obtained.

The acoustic buoy 41 converts a beam formed by phasing a received signal output from a linearly arranged receiver element group into a radio signal and transmits the radio signal.

The sonobuoy signal processor 42 mounted on the surface ship 12 has a receiver (not shown) for receiving and processing radio signals from a plurality of acoustic buoys, and a narrow band output from the receiver. A signal processor for processing; and a display for displaying a spectrum of the signal subjected to the narrow band processing.

In the same manner as in the first embodiment, the reception signal specified (specified and input by looking at the display) from the reception signals for each acoustic buoy output from the receiver of the sonobuoy signal processor 42. , And a selected signal and H
A correlation operation circuit that performs a correlation operation with the output signal of the phase adjuster 6 of the ULL sonar 16 and an output signal of the correlation operation circuit and an output signal of the hull sonar phase adjuster that are switched in response to a single / integral switching command to HULL. Signal processor 7 of sonar 16
And a signal switching circuit for supplying the signal to the

FIG. 5 shows a passive sonar signal processing method according to a third embodiment of the present invention. The third embodiment is of a simple type that easily detects a target and limits the position. A plurality of acoustic buoys 41 in the second embodiment and a receiver 51 that receives and processes radio signals of the plurality of acoustic buoys 41 are used.
And a selection circuit 52 for selecting a signal related to the two specified sound buoys from the received signals, a correlation calculation circuit 53 for performing a correlation calculation for the signals related to the selected two sound buoys, and performing the correlation calculation. A signal processing circuit 54 for integrating the signal is provided, and a display 55 for displaying the signal processed signal in the horizontal axis direction and the vertical axis time. The selection is designated by the operator while viewing the display on the display 55.

[0047]

As described above, the passive sonar signal processing method according to the present invention employs a T
When the target detection is displayed on the display of the ASS (first invention) or the display of the signal processing device (second invention),
The phasing signal is correlated with the phasing signal of the hull sonar performing a passive operation, and the result is given to a signal processor of the hull sonar to perform an integration process and display the result. Therefore, since the processing gain is improved as compared with the hull sonar alone in the passive operation, the hull sonar can be expected to detect the target in the passive operation following the detection by the TASS or a plurality of acoustic buoys. It can be realized in a short time due to the occupation difference between the installation positions of a plurality of acoustic buoys and the receiving array of hull sonars, and there is an effect that oversight of the transition time to hull sonar active operation can be reduced. In the third invention, the correlation processing is performed between two acoustic buoys selected from the plurality of acoustic buoys in the second invention, so that the target detection and the position localization can be performed more easily than in the first invention and the second invention. There are also effects that can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a passive sonar signal processing method according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of a passive sonar signal processing method (integrated processing method) of the present invention.

FIG. 3 is a radiation noise characteristic diagram of a submarine.

FIG. 4 is a diagram illustrating a passive sonar signal processing method according to a second embodiment of the present invention.

FIG. 5 is a configuration block diagram of a passive sonar signal processing method according to a third embodiment of the present invention.

FIG. 6 is a configuration block diagram of a towed passive sonar (TASS).

FIG. 7: A conventional bottom sonar (hull sonar: HU)
FIG. 3 is a configuration block diagram of an LL sonar).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wave receiving array 2 phase adjuster 3 signal processor 4 display 5 a wave receiving array 6 phase adjuster 7 signal processor 8 display 9 selection circuit 10 correlation operation circuit 11 signal switching circuit 12 signal ship 13 submarine 15 submarine 15 TASS 16 HULL Sonar 41 acoustic buoy 42 sonobuoy signal processing device 51 receiver 52 selection circuit 53 correlation operation circuit 54 signal processing circuit 55 display

Claims (3)

(57) [Claims] 1. A receiving array in which receiving elements are linearly arranged, a phasing device for phasing a received signal output from a receiving element group to form a beam, and a narrowed phasing signal. A towed passive sonar (TASS) equipped with a signal processor for performing band processing and a display for displaying a spectrum of a signal subjected to narrow band processing.
A wave receiving array in which wave receiving elements are arranged in a plane, a wave shaper for forming a beam by phasing a received signal output from a wave receiving element group, and performing integration processing of an input signal. A sonar (hull sonar) equipped with a signal processor and a display unit for performing an interpolation process on the signal subjected to the integration process and displaying the signal on the display of the horizontal axis direction and the vertical axis time; and an output signal of the TASS phase adjuster A selection circuit that selects a signal of only a designated channel from among the following: a correlation operation circuit that performs a correlation operation between the selected signal and an output signal of a hull sonar phaser;
A signal switching circuit for switching between an output signal of a correlation operation circuit and an output signal of a hull sonar phaser in response to a single / integral switching command and providing the output signal to a hull sonar signal processor; method. 2. A plurality of acoustic buoys for converting a beam formed by phasing a received signal output by a group of linearly arranged receiver elements into a radio signal and transmitting the radio signal; A hull sonar according to claim 1, comprising a receiver for receiving and processing the wireless signal, a signal processor for narrow-band processing the output of the receiver, and a display for spectrum-displaying the narrow-band processed signal; A selection circuit for selecting a specified reception signal from the reception signals for each acoustic sonobuoy output by the receiver of the sonobuoy signal processing device; and a correlation operation between the selected signal and the output signal of the hull sonar phaser A signal switching circuit that switches between the output signal of the correlation operation circuit and the output signal of the hull sonar phaser in response to a single / integral switching command and provides the output signal to the signal processor of the hull sonar; A passive sonar signal processing method, comprising: 3. A plurality of acoustic buoys according to claim 2;
A receiver for receiving and processing radio signals of a plurality of acoustic buoys;
A selection circuit that selects a signal related to the two specified sound buoys from the received signals; a correlation calculation circuit that performs a correlation calculation on the signals related to the selected two sound buoys;
A signal processing circuit for integrating the correlation-calculated signal;
A display for displaying the processed signal in the horizontal axis direction and the vertical axis time; and a passive sonar signal processing method.