JP2000019252A - Circuit and method for eliminating navigating noise - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with any speed even under complex ocean wave conditions by comparing the signal level values of the left and right reception channels in the advancing direction of a ship, and by performing correction based on the comparison result. SOLUTION: A circuit 11-i for eliminating navigation noise being applied to an underwater-sound-wave-searching device being rigged in a ship is provided with, for example, a divider 20, and operation circuit 21 for calculating an average value, a multiplier 22, and a subtractor 23. The ratio of the reception level of a signal 18 on the starboard side to a reception signal 19 of, for example, the channel of the port side with reception directivity that is symmetrical with respect to the advance direction of the ship is obtained by the divider 20, the ratio of all symmetric channels is averaged by the operation circuit 21, and the signal of the channel of the port side is multiplied by the obtained value as a correction value. Furthermore, the difference of the reception level for every symmetric channel is calculated by the subtractor 23 for detecting as the reception level of radiation noise of an underwater target. The detected signal is processed by a specific method including integral processing or the like, and is displayed on a CRT or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cruising noise elimination circuit and a cruising noise elimination method, and more particularly to a CRT for radiating noise generated from a target object underwater by mounting it on a ship.
The present invention relates to a navigation noise elimination circuit and a navigation noise elimination method in an underwater acoustic sounding device for displaying on a display such as a (CathodeRay Tube) and determining a target object based on the intensity of the luminance signal.

[0002]

2. Description of the Related Art In general, in a submersible acoustic sounding device mounted on a ship, there is a problem of running noise generated when the ship sails on the sea. This running noise is mainly generated when the wave front of the ocean collides with the bow, and the reception level of the running noise is synchronized with the cycle of the wave, for example, as shown in FIG. Change. That is, in FIG. 3, the value of the reception level 2 changes sharply as indicated by the solid line 3 with respect to the passage of time 1.

[0003] In addition, in an underwater acoustic probe installed on a ship, an SN ratio (Signal signal) is obtained by integrating a received signal.
/ Noise) and performing signal processing for detecting underwater target signals. However, as shown in FIG. 9, the traveling noise generated when the ship sails varies the reception level of each horizontal reception channel in a complicated manner depending on the speed of the ship and the state of ocean waves. .

[0004] That is, assuming that the azimuth 0 degree is the traveling direction of the ship, the reception level with respect to the relative azimuth 4 changes as indicated by the solid line 5 at the time of high speed cruising, and the relative azimuth distribution of the reception level changes at the time of high speed cruising. It changes like the solid line 6.

[0005]

In the above-described underwater acoustic sounding device, as shown in FIG. 8, since the running noise generated when the ship sails is extremely large, the sound generated from the underwater target object is generated. The disadvantage is that it is extremely difficult to detect the radiated noise.

Further, as shown in FIG. 9, since the reception level of each horizontal reception channel changes in a complicated manner depending on the speed of the ship and the conditions of ocean waves, only the traveling noise component is removed. However, there is a disadvantage that the ability to detect a weak underwater target signal with respect to a drastically changing running noise is low.

[0007] Although processing for removing the frequency band components of self-noise and radiated noise that have been fixedly generated has been practically used, it is not possible to remove navigation noise that changes in a complicated manner.

[0008] Here, Japanese Patent Application Laid-Open No. 2-275379 relates to a sonar for an underwater vehicle such as a submarine, and cannot remove the running noise generated when the ship sails on the sea. Further, the running noise cannot be removed by the scanning sonar disclosed in JP-A-59-188584.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a navigation noise elimination circuit and a navigation noise elimination method.

[0010]

According to the present invention, there is provided a navigation noise elimination circuit comprising: a port n-th direction (n is an integer of 2 or more; the same applies hereinafter) and a starboard n-th symmetric with respect to the traveling direction of a ship; Error detecting means for detecting an error between the port side nth received signal and the starboard side nth received signal respectively received from the direction, and correcting means for correcting the detected error, the port side after this correction The reception signal and the starboard reception signal are displayed.

[0011] In the running noise elimination method according to the present invention, the signals are received from the port n-th direction (n is an integer of 2 or more, the same applies hereinafter) and the starboard n-th direction which are symmetrical to the traveling direction of the ship. An error detection step of detecting an error between the port side n-th reception signal and the starboard side n-th reception signal; and a correction step of correcting the detected error, the corrected port side reception signal and the starboard side reception signal It is characterized in that a signal is displayed.

In short, according to the present invention, the received signal level of the underwater sound wave received by the underwater sound wave sounding device is compared with the received signal level of the receiving channel which is symmetrical with respect to the traveling direction of the ship, and the received signal level of either the left or right is compared. Is large, this is corrected as radiation noise of the underwater target, then converted into a luminance signal, and displayed on a display such as a CRT.

Here, the running noise of the ship is distributed symmetrically with respect to the traveling direction of the hull, as shown in FIG. 9, and the influence of waves acts on the ship almost equally. , The received signal level fluctuates simultaneously as shown in FIG. Therefore, the reception signal levels of the reception channels in the azimuth symmetric with respect to the bow direction are basically equal. If radiated noise from underwater targets is received in addition to the running noise, only the left and right received signal levels will increase, so comparing the received levels of the left and right receiving channels will reduce the running noise component. It is possible to remove and extract only the radiation noise component from the underwater target.

Also, depending on the relative relationship between the direction of arrival of the ocean wave and the direction of travel of the ship, the reception levels of the left and right reception channels may not be equal, and errors may occur in the reception levels of the left and right reception channels. . This is a phenomenon that occurs when a ship is receiving a shear wave. This error can be corrected by calculating the ratio of reception channels symmetrical to the traveling direction and the average value thereof, and using the average ratio.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same reference numerals are given to the same parts as those in the other drawings.

FIG. 2 is a block diagram showing the configuration of an underwater acoustic search device including a navigation noise removing circuit according to the present invention. In the figure, an underwater acoustic detection device is provided in the water to receive an incoming sound wave, and a delay process is performed on a signal received by the receiver 7 to realize n reception channels. Phasing circuits 9-1 to 9-n, and cruising noise elimination circuits 11-1 to 11-3 for performing a process of removing cruising noises from the received signals 10-1 to 10-n for each reception channel.
11-n, integration circuits 13-1 to 13-n which perform integration processing on target signal detection values 12-1 to 12-n which are signals after the removal of the running noise, and a display of the signal 14 after the integration. And a display 16 such as a CRT for displaying an output signal 16 of the display processing circuit 15. Note that the delay phasing circuit 9-i (i = 1 to
n; the same applies hereinafter) and the integration circuits 13-i are required for the number of reception channels having the reception directivity in the horizontal direction (n).

The running noise elimination circuit 11-i in FIG. 2 will be described with reference to FIG. FIG. 1 is a block diagram showing a first embodiment of a running noise elimination circuit according to the present invention. Referring to FIG. 1, each running noise removal circuit 11-i
Is composed of a divider 20, an arithmetic circuit 21 for calculating an average value of the division result, a multiplier 22 having the calculation result as one input, and a subtractor 23.

Next, the operation of the underwater acoustic sounding device including the running noise removing circuit according to the present invention will be described in detail with reference to FIGS.

The signal 8 received by the receiver sensor 7 attached to the ship is input to the delay phasing circuit 9-i. At this time, for example, as shown in FIG. 3, the signal is converted into a reception channel reception signal 10-i having horizontal reception directivity. That is, in the figure, the reception level value of the reception channel on the starboard side with respect to the traveling direction of the ship 31 is R1.
To R7, and the reception level values of the reception channels on the port side are L1 to L7.

Returning to FIG. 2, the reception signal 10 of the reception channel
-I is input to the running noise removal circuit 11-i. In the running noise removing circuit 11-i, processing for removing the running noise is performed.

Referring to FIG. 1, a divider 20 calculates a reception level ratio of the reception signal 18 of the starboard side reception channel to the reception signal 19 of the port side reception channel having the reception directivity symmetrical to the traveling direction of the ship. I do. In this case, the arithmetic circuit 21 calculates the average value of the received signals for all the symmetrical port side reception channels and starboard side reception channels of the ship. The average value calculated by the arithmetic circuit 21 is used as a correction value, and a multiplier 22 multiplies the reception channel on the port side by the correction value.

When the divider 20 calculates the reception level ratio of the port side reception channel to the starboard side reception channel, the multiplier 22 applies a correction value to the starboard side reception channel.

Further, in the running noise elimination circuit 11-i, the subtractor 23 calculates the difference of the reception level value for each of the reception channels having the reception directivity symmetrical with respect to the traveling direction, and calculates the radiation noise of the underwater target. Detected as received level. In this case, the subtractor 23 calculates and outputs the reception channel output level 24 on the port side and the reception channel output level 25 on the starboard side.

Returning to FIG. 2, the target signal detection value 12-i for each reception channel is input to the integration circuit 13-i, and the S / N ratio is improved by the integration effect. The integration result 14 of the integration circuit 13-i is input to the display processing circuit 15, which converts the signal processing result for each reception channel into a display luminance signal 16 for each direction and displays it on a display 17 such as a CRT.

Here, in the present circuit, the following (1) and (2) are used to remove the running noise of the underwater acoustic probe.
The characteristics of the running noise shown in Fig. 1 are used.

(1) The horizontal reception level distribution of the running noise is symmetrical with respect to the traveling direction of the ship.

(2) The reception level of the running noise due to ocean waves fluctuates simultaneously with the left and right with respect to the wave receiving sensor of the underwater acoustic sounding device.

By utilizing this characteristic, the circuit performs the following running noise removing method. That is, the port side n-th side symmetrical with respect to the traveling direction of the ship
Port nth received from the direction and starboard nth direction respectively
An error detecting step of detecting an error between the received signal and the starboard-side n-th received signal, and a correcting step of correcting the detected error, including displaying the corrected port-side received signal and the starboard-side received signal. They do it.

Next, an example of the configuration of an underwater sonic search device including the navigation noise elimination circuit of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 4, the underwater acoustic probe includes:
It comprises a receiver 7, an input processor 27, a signal processor 28, a post-processor 29 and a display 17.

The input processor 27 in the figure includes an amplifier circuit 26 for amplifying a received signal and a delay phasing circuit 9 for generating a reception channel. The signal processor 28 includes the running noise removing circuit 11 and the integrating circuit 13. The post-processor 29 includes the display processing circuit 15
It is comprised including.

Here, the running noise removing circuit 11 in FIG.
As shown in FIG. 5, inputs the starboard-side reception level values (R1 to Rn) 18-1 to 18-n and the port-side reception level values (L1 to Ln) 19-1 to 19-n. Dividers 20-1 to 20-n and reception channel ratio values (K1 to Kn) 30-1 to 30 output from the dividers
An arithmetic circuit 21 for calculating the average value K0 of −n, and a multiplier 22-1 for multiplying the calculated average value K0 by the reception level values L1 to Ln of the port-side reception channel to be corrected.
22-n, and subtracters 23-1 to 23-n for subtracting the result of the multiplication from the reception level values 18-1 to 18-n of the receiving channel on the starboard side. From the subtracters 23-1 to 23-n, the corrected starboard-side reception level values (R1 to Rn) 24-1 to 24-n and the portside reception level values (L1 to Ln) 25-1 to 25-n are output. Is output.

The operation of this circuit will be described in detail with reference to FIGS. Referring to FIG. 5, the reception level values R1 to Rn and L1 to Ln of the reception channel having the reception directivity shown in FIG.

The input signal is input to the divider 20-i for each reception channel symmetrical with respect to the traveling direction of the ship, and the ratio value K1 of the reception signal level value is calculated.

Next, ratio values K1 to Kn of all reception channels
Is calculated. This calculated average value K0
Are respectively multiplied by the multipliers 22-i with the reception level values L1 to Ln of the port-side reception channels to be corrected. Finally, the receiving level values R1 to Rn on the starboard side and the corrected receiving level values L1 to Ln on the port side are subtracted by the subtractor 23-i, and the calculation result is output as a signal detection level of each receiving channel. .

In short, in this circuit, in the underwater sound wave reception signal processing of the underwater sound wave detection device mounted on the ship, the running noise component of the ship is removed from the underwater sound wave reception signal.
The reception levels of the reception channels that are symmetrical with respect to the traveling direction of the ship are compared, and the difference is detected as a radiation noise signal of the underwater target. By doing so, in the underwater acoustic sounding device installed on the ship, only the traveling noise component can be effectively removed by a very simple process.

Next, a second embodiment of the present invention will be described.
This will be described with reference to the drawings. FIG. 6 shows an underwater acoustic search device according to the second embodiment. In the figure, the running noise is removed after the frequency analysis.

Here, the running noise removing circuit 11 in FIG.
Performs a process of removing a portion corresponding to a running noise level by using a reception signal level of an input reception channel. On the other hand, in FIG. 6, F
FT (Fast Fourier Transformer)
m) Frequency analysis circuits 32-1 to 32-n for performing processing and the like are provided, and the received signal is decomposed into reception levels for several frequency components, and then the running noise removal processing for each frequency component is performed. .

In this case, a running noise removing circuit is provided for each frequency band. That is, the frequency analysis circuit 32-1
, Three running noise removing circuits 11-1a (band a), 11-1b (band b) and 11-1c (band c)
Is provided. Similarly, the running noise elimination circuits 11-2a (band a) and 11-2 correspond to the frequency analysis circuit 32-2.
b (band b) and 11-2c (band c).
Similarly, the frequency analysis circuit 32-n is provided with running noise elimination circuits 11-na to 11-nc. With such a configuration, it is possible to more effectively remove the traveling noise component in accordance with the frequency characteristics of the traveling noise.

The running noise removing circuit 11-i for each frequency component
Outputs of a to 11-ic are output from band addition circuits 33-1 to 33-33.
-N, add all the frequency components for each reception channel, and convert them into signals for each direction of the reception channel. Then, the data is integrated by the integration circuits 13-1 to 13-n, processed by the display processing circuit 15, and displayed on the display 17 such as a CRT.

FIG. 7 shows a modification of the second embodiment. In the figure, the output of the navigation noise elimination circuits 11-ia to 11-ic for each frequency component is not subjected to the band addition processing for the reception signal for each direction of the reception channel, but the frequency component for each reception channel is integrated into an integration circuit 13 -Ia to 13-ic. Thus, the frequency analysis data from which the running noise component has been removed from the received signal can be selected by the display selection circuit 34 and displayed on the display 17 such as a CRT via the display processing circuit 15.

That is, in any of the embodiments, in order to remove the running noise, the reception levels of the reception channels having the reception directivity in the symmetrical directions with respect to the traveling direction of the ship are compared, and the difference is determined underwater. It is detected as the target radiation noise. Then, in order to correct the reception level difference between the starboard side and the port side of the ship due to the relative relationship between the direction of travel of the ship and the direction of arrival of the ocean waves, the directivity should be symmetrical with respect to the direction of travel of the ship. The average value of the ratio of the reception level between the starboard-side reception channel and the port-side reception channel having the following equation is used.

By performing such a correction process, it is possible to effectively remove the traveling noise that changes in a complicated manner depending on the speed of the ship or the state of ocean waves by a very simple process. Further, in the present invention, in this correction processing, since there are no left and right receiving channels in the receiving channel in the bow direction and the stern direction of the ship, the running noise cannot be removed.

Note that the effect of the present circuit is effective only when the ship is going straight ahead as a restriction on its principle, and when the ship is anchored or changing the course, the running noise is reduced as described above. No effect is expected because it does not have That is, if the ship is anchored, needless to say according to the present invention,
Good reception without being affected by the running noise. Further, when the ship is changing the course, the received signal is not symmetrical in the left-right direction. Therefore, according to the present invention, it is impossible to receive the signal satisfactorily due to the influence of the running noise.

In connection with the description of the claims, the present invention can further take the following aspects.

(1) Comparison means for comparing the port side reception signal and the starboard side reception signal at the left-right symmetric position received by the ship, and based on the comparison result, the port side reception signal and the starboard side reception signal are compared. A traveling noise elimination circuit, comprising: a correction unit for performing a correction.

(2) The comparing means is a ratio which is a ratio of one of the port side reception signal and the starboard side reception signal to the other of the port side reception signal and the starboard side reception signal at a plurality of symmetrical positions around the vessel. A ratio calculating means for calculating respective values, and an average value calculating means for calculating an average value of all of the ratio values calculated by the ratio calculating means, wherein the correcting means comprises an average calculated by the average value calculating means. The running noise elimination circuit according to (1), wherein the signal is corrected by multiplying the one signal by a value.

(3) A comparison step of comparing the port side reception signal and the starboard side reception signal at the symmetrical position received on the ship, and based on the comparison result, the port side reception signal and the starboard side reception signal are compared. A running noise elimination method.

(4) In the comparing step, the ratio of one of the port side reception signal and the starboard side reception signal to the other of the port side reception signal and the starboard side reception signal at a plurality of left-right symmetrical positions around the vessel. Calculating each ratio value, calculating an average value of all the calculated ratio values, and correcting the signal by multiplying the one average signal by the calculated average value in the correcting step. (3) The method for removing running noise according to (3).

[0050]

As described above, the present invention is characterized in that the running noise is distributed symmetrically with respect to the traveling direction of the ship, and the reception levels of the left and right reception channels with respect to the traveling direction of the ship are provided. By comparing the values and making corrections based on the comparison result, there is an effect that any traveling noise at any speed can be easily removed. In addition, the navigation noise has the characteristic that fluctuations in the reception level of the navigation noise due to waves occur in all directions at the same time. The difference between the receiving channel on the starboard side and the port side can be effectively corrected by using the average result of Therefore, there is an effect that an error between the reception level values of the receiving channels on the starboard side and the port side, which occurs when receiving the signal, can be corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic operation of a running noise elimination circuit according to the present invention.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a horizontal directivity center azimuth distribution of a receiving channel of the underwater acoustic sounding device including the navigation noise removing circuit according to the present invention.

FIG. 4 is a block diagram showing a configuration example of a running noise elimination circuit of the present invention.

FIG. 5 is a block diagram showing an operation of a further embodiment of the running noise elimination circuit of FIG. 4;

FIG. 6 is a block diagram showing a second embodiment of the present invention.

FIG. 7 is a block diagram showing a modification of the second embodiment of the present invention.

FIG. 8 is a diagram illustrating an example of a time change of a running noise.

FIG. 9 is a diagram illustrating an example of an azimuth distribution of running noise.

[Explanation of symbols]

 7 receiver 9-1 to 9-n delay phasing circuit 11-1 to 11-n navigation noise elimination circuit 13-1 to 13-n integration circuit 15 display processing circuit 17 display 20 divider 21 average value calculation Circuit 22 Multiplier 23 Subtractor 31 Ship 32-1 to 32-n Frequency analysis circuit 33-1 to 33-n Band addition circuit

Claims (10)

[Claims] 1. A port side n-th received signal and a starboard side respectively received from a port side n-th direction (n is an integer of 2 or more, the same applies hereinafter) and a starboard side n-th direction symmetrical with respect to a traveling direction of a ship. Error detecting means for detecting an error with the side n-th received signal; and correcting means for correcting the detected error. The corrected port-side received signal and the starboard-side received signal are displayed. A running noise elimination circuit, characterized in that: 2. A ratio calculation for calculating an n-th ratio value that is a ratio of one of the port-side n-th received signal and the starboard-side n-th received signal to the other signal. Means, and average value calculating means for calculating an average value of all of the first to n-th ratio values calculated by the ratio calculating means, wherein the correcting means comprises an average value calculated by the average value calculating means. 2. The navigation noise elimination circuit according to claim 1, wherein the signal is corrected by multiplying the one signal by the second signal. 3. The apparatus according to claim 1, further comprising integrating means for integrating the port side reception signal and the starboard side reception signal corrected by the correction means, and displaying the integrated signal. 2. The running noise removing circuit according to 2. 4. The apparatus further includes means for performing a frequency analysis on the port side n-th received signal and the starboard side n-th received signal, wherein the port side n-th received signal and the starboard side n-th received signal after the frequency analysis are performed. The running noise elimination circuit according to any one of claims 1 to 3, wherein the error detection is performed by the error detection means for each frequency band. 5. The navigation noise according to claim 4, wherein the result of the error detection by said error detection means for each of said frequency bands is integrated by said integration means for each of said frequency bands. Elimination circuit. 6. A port side n-th received signal and a starboard side respectively received from a port side n-th direction (n is an integer of 2 or more, the same applies hereinafter) and a starboard side n-th direction symmetrical with respect to a traveling direction of a ship. An error detecting step of detecting an error with the side n-th received signal, and a correcting step of correcting the detected error are included, and the corrected port-side received signal and the starboard-side received signal are displayed. A method for removing running noise, comprising: 7. In the error detecting step, an n-th ratio value that is a ratio of one of the port-side n-th received signal and the starboard-side n-th received signal to the other signal is calculated. An average value of all the calculated first to n-th ratio values is calculated, and in the correcting step, the calculated average value is multiplied by the one signal to correct the signal. Item 7. The method for removing running noise according to Item 6. 8. The apparatus according to claim 6, further comprising an integration step of integrating the port side reception signal and the starboard side reception signal after the correction in the correction step, and displaying the integrated signal. 7. The running noise removing method according to 7. 9. The method further includes the step of performing frequency analysis on the port side n-th received signal and the starboard side n-th received signal, and regarding the port side n-th received signal and the starboard side n-th received signal after the frequency analysis. The method according to any one of claims 6 to 8, wherein the error detection is performed by the error detection step for each frequency band. 10. The running noise according to claim 9, wherein the result of performing the error detection by the error detection step for each of the frequency bands is integrated by the integration step for each of the frequency bands. Removal method.