JP2012202837A - Passive sonar signal processing device, passive sonar signal processing method and passive sonar signal processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a passive sonar signal processing device free from the occurrence of any blind zone or ghost.SOLUTION: A passive sonar signal processing device comprises differential processing means that calculates the increase/decrease ratio of signal levels between orientation channels; integral processing means that calculates the total increase/decrease ratio for each section determined on the basis of the increase/decrease ratio based on the increase/decrease ratio of orientation channels included in the section; and S/N ratio detection processing means that calculates the S/N ratios of the signals on the basis of the total increase/decrease ratio of a plurality of mutually different orientation channels selected on the basis of the value of the total increase/decrease ratio.

Description

  The present invention relates to a passive sonar signal processing device, a passive sonar signal processing method, and a passive sonar signal processing program, and more particularly to a passive sonar signal processing device, a passive sonar signal processing method, and a passive sonar signal processing method used for processing to detect the direction of a signal emitted by a target. The present invention relates to a passive sonar signal processing program.

  Commonly known ordinary passive sonar devices are described in Patent Documents 1 and 2, for example.

The basic principle of the passive sonar device is not limited to the examples of Patent Documents 1 and 2, but a plurality of arrays are arranged, and the receiving directionality is given to a specific direction by phasing processing. For wave signals
(1) Feature frequency is extracted by frequency analysis. (2) Processing for calculating the signal arrival direction from the phase difference or the energy distribution of the received signal is performed. Whatever pre-processing or post-processing is performed, ultimately, the characteristic frequency of the sound emitted by the target and its direction are detected.

  By the way, since the background noise level always changes due to random noise, it is difficult to detect a signal by simply setting a threshold value. Therefore, it is essential to extract the S / N ratio (Signal / Noise ratio) regardless of the processing system.

  In general, AGC processing for estimating a background noise level from statistical data such as moving average from currently acquired data and normalizing the background noise level is well known.

  However, the method of estimating the background noise level by statistical processing always depends on the past data, so if the background noise level fluctuates significantly or if an abnormal value is mixed, signal detection is performed normally. There is a problem that makes it impossible.

  As a technique for solving this problem, a technique described in Patent Document 3 has been proposed.

  The technique described in Patent Document 3 uses three integrated output signals, includes a minimum value detection circuit, and uses the output signal of the minimum value detection circuit to make the background noise level of a received signal having a wide dynamic range uniform. The present invention relates to an automatic gain adjustment circuit.

  In addition, the techniques described in Patent Documents 4 and 5 are related to the present invention.

Japanese Patent Publication No. 6-93016 JP-A-4-143683 JP 62-245173 A JP-A-5-66256 JP-A-8-184661

  In ordinary technology, BDAGC processing has been used as a processing method for detecting the direction of a signal emitted from a target. This is a quadratic curve regression calculation using the adjacent azimuth data to be processed with respect to the frequency processing band addition data for each azimuth at an arbitrary time, and the result is an estimated value of the background noise level. This is a method of calculating the S / N ratio by normalization.

However, when BDAGC is used, if a strong signal level is detected in a certain direction (see FIG. 1), the estimated background noise level on both sides of the direction is increased by the quadratic curve regression calculation. There is a problem that it becomes a blind zone in which the / N ratio is not calculated (see FIG. 2).
Furthermore, for the direction closest to the direction that becomes the blind zone, since the estimated background noise level is significantly reduced by the quadratic curve regression calculation, the signal S / N ratio is calculated by performing normalization with that value, There is a problem that a ghost in which the signal S / N ratio is detected in an unintended direction occurs (see FIG. 2).

  An object of the present invention is to provide a passive sonar signal processing apparatus, a passive sonar signal processing method, and a passive sonar signal processing program in which neither a blind zone nor a ghost occurs.

  According to the first aspect of the present invention, the differential processing means for calculating the increase / decrease ratio between the azimuth channels of the signal level and the azimuth included in the interval for each interval determined based on the value of the increase / decrease ratio Based on the increase / decrease ratio of the channel, the integration processing means for calculating the total increase / decrease ratio, and based on the total increase / decrease ratio of the plurality of different azimuth channels selected based on the value of the total increase / decrease ratio, There is provided a passive sonar signal processing apparatus comprising: S / N detection processing means for calculating an S / N ratio of a signal.

  According to the second aspect of the present invention, the differential processing step for calculating the increase / decrease ratio between the azimuth channels of the signal level and each interval determined based on the value of the increase / decrease ratio are included in the interval. An integration processing step for calculating a total increase / decrease ratio based on the increase / decrease ratio of the azimuth channel, and based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio And a S / N detection processing step for calculating an S / N ratio of the signal. A passive sonar signal processing method is provided.

  Furthermore, according to a third aspect of the present invention, there is provided a passive sonar signal processing program for causing a computer to function as a passive sonar signal processing apparatus, wherein the computer calculates a ratio of increase / decrease between azimuth channels of signal levels. Differentiation processing means, integration processing means for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section, and the total increase / decrease ratio S / N detection processing means for calculating the S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the signal, and passive sonar for functioning as S / N detection processing means A signal processing program is provided.

  According to the present invention, neither a blind zone nor a ghost occurs.

It is a figure which shows an example of the input signal for showing the effectiveness of this invention. It is a figure for demonstrating the problem at the time of using a normal technique. It is a block diagram which shows the whole structure of the passive sonar signal processing apparatus by embodiment of this invention. It is a figure which shows the increase / decrease ratio for every azimuth | direction channel which is an output signal of the differentiation process part shown in FIG. It is a figure which shows the total increase / decrease ratio for every azimuth | direction channel which is an output signal of the one cross integration process part shown in FIG. It is a figure which shows S / N ratio for every azimuth | direction channel which is an output signal of the S / N detection process part shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 2 shows the overall configuration of the passive sonar signal processing apparatus according to the present embodiment.

  Referring to FIG. 2, the passive sonar signal processing apparatus according to the present embodiment includes a differential processing unit 1 that calculates an increase / decrease ratio between azimuth channels of signals for each azimuth channel received by the passive sonar, a section in which the increase / decrease ratio is 1. One cross integration processing unit 2, which calculates the total increase / decrease ratio by multiplying the interval where the increase / decrease ratio exceeds 1 and the interval where the increase / decrease ratio is less than 1 by the increase / decrease ratio of the azimuth channel included in that interval The signal S / N ratio for each azimuth channel is obtained by extracting the increase / decrease ratio and the total increase / decrease ratio not exceeding 1 as a pair and taking the geometric mean of the total increase / decrease ratio exceeding 1 and the inverse of the total increase / decrease ratio not exceeding 1 S / N calculation processing unit 3 is calculated.

  Next, a passive sonar signal processing method performed by the passive sonar signal processing apparatus according to the present embodiment will be described.

  The differential processing unit 1 calculates the signal increase / decrease ratio diff [ch + 1] for each azimuth channel by the equation (1).

ch:受信チャネル（方位） (ch=0,1,・・・,N)
ワンクロス積分処理部２は、（２）式により、信号増減比が１未満であることが続く区間、信号増減比が１を超えることが続く区間及び信号増減比が１である区間毎にその区間に含まれる方位チャネルの増減器を掛け合わせることにより合計増減比Integral[j+1]を算出する。

ch: Reception channel (azimuth) (ch = 0,1, ..., N)
The one-cross integration processing unit 2 uses the equation (2) to calculate the interval for each interval where the signal increase / decrease ratio is less than 1, the interval where the signal increase / decrease ratio exceeds 1 and the interval where the signal increase / decrease ratio is 1. The total increase / decrease ratio Integral [j + 1] is calculated by multiplying the increase / decrease units of the azimuth channels included in the section.

但し、
信号増減比が１未満であることが続く区間については、
Diff[i-1]=>1, Diff[i]<1, Diff[i+1]<1,・・・,Diff[j]<1, Diff[j+1]=>1
信号増減比が１を超えることが続く区間については、
Diff[i-1]=<1, Diff[i]>1, Diff[i+1]>1,・・・,Diff[j]>1, Diff[j+1]=<1
信号増減比が１である区間については、
Diff[i]=Diff[i+1]=…Diff[j]=1
なおそのとき、（２）式によっては、i番目の方位チャネルからｊ番目の方位チャネルについての合計増減比を計算することができないが、それらのチャネルについての合計増減比を１とする。すなわち、
Integral[i]=integral[i+1]=integral[j]=1
とする。

However,
For the section where the signal increase / decrease ratio continues to be less than 1,
Diff [i-1] => 1, Diff [i] <1, Diff [i + 1] <1, ..., Diff [j] <1, Diff [j + 1] => 1
For sections where the signal increase / decrease ratio continues to exceed 1,
Diff [i-1] = <1, Diff [i]> 1, Diff [i + 1]> 1, ..., Diff [j]> 1, Diff [j + 1] = <1
For sections where the signal increase / decrease ratio is 1,
Diff [i] = Diff [i + 1] =… Diff [j] = 1
At this time, the total increase / decrease ratio for the i-th azimuth channel to the j-th azimuth channel cannot be calculated according to equation (2), but the total increase / decrease ratio for these channels is set to 1. That is,
Integral [i] = integral [i + 1] = integral [j] = 1
And

  The S / N ratio detection processing unit 3 calculates the signal S / N ratio based on the two total increase / decrease ratios for the azimuth channel whose total increase / decrease ratio exceeds 1. That is, the S / N ratio detection processing unit 3 checks the total increase / decrease ratio of all the azimuth channels. Then, for each azimuth channel having a total increase / decrease ratio exceeding 1 (hereinafter referred to as a “first primary azimuth channel”), an azimuth channel closest to the target azimuth channel (hereinafter referred to as “first primary azimuth channel”) is less than 1 , “Secondary target orientation channel”). Then, the signal S / N ratio S of the azimuth channel adjacent to the primary azimuth channel is the geometric average of the total increase / decrease ratio of the primary azimuth channel and the reciprocal of the total increase / decrease ratio of the second azimuth channel. Calculate as / N [ch-1]. A calculation formula for this calculation is expressed by the following equation (3).

ch :第１次着目方位チャネル
ch’:第２次着目方位チャネル
合計増減比が１を超えない方位チャネルについては、信号Ｓ／Ｎ比率を１とする。

ch: Primary orientation channel
ch ′: Secondary attention azimuth channel For the azimuth channel whose total increase / decrease ratio does not exceed 1, the signal S / N ratio is set to 1.

  According to the present embodiment, there is an effect that neither a blind zone nor a ghost occurs.

  The reason for this is that in the process of this embodiment, instead of the process of estimating the background noise level or the like from the input signal, the increase / decrease ratio for each direction is directly calculated by differential processing, and the total increase / decrease ratio is calculated by one-cross integration processing. Since the S / N ratio for each direction is calculated based on the total increase / decrease ratio by the S / N ratio detection process, the peak that can be confirmed in the input signal and the increase / decrease ratio are directly calculated without estimating the noise level or the like. That is.

  Next, a passive sonar signal processing method performed by the passive sonar signal processing apparatus will be described using a specific example.

  As shown in FIG. 3, it is assumed that data obtained by adding energy in a certain frequency band for each reception azimuth channel is input for 36 azimuth channels at a certain time. Referring to FIG. 3, the signal level of the 33rd azimuth channel is about 650, the signal level of the 34th azimuth channel is about 1700, the signal level of the 35th azimuth channel is about 550, and The signal level is about 100.

  The differentiation processing unit 1 calculates the signal increase / decrease ratio for each azimuth by the above-described equation (1). The result is shown in FIG. Referring to FIG. 4, the increase / decrease ratio of the 33rd azimuth channel is about 6.5 (= 650/100), the increase / decrease ratio of the 34th azimuth channel is about 2.6 (= 1700/650), The increase / decrease ratio of the azimuth channel is about 0.3 (= 550/1700), the increase / decrease ratio of the 36th azimuth channel is about 0.2 (= 100/550), and the increase / decrease ratio of the other azimuth channels is 1 ( = 100/100).

  Specifically, the one-cross integration processing unit 2 is a section in which the increase / decrease ratio of the section composed of the 33rd azimuth channel and the 34th azimuth channel continues to exceed 1, so the increase / decrease ratio of the 33rd azimuth channel (= about 6.5) and the increase / decrease ratio of the 34th azimuth channel (= about 2.6), the value (= about 16.9) obtained by multiplying the 35th azimuth channel is the 35th azimuth channel that is the next azimuth channel. Calculated as the total increase / decrease ratio of the azimuth channel. Further, the one-cross integration processing unit 2 is specifically a section in which the ratio from the 35th azimuth channel to the first azimuth channel via the 36th azimuth channel continues to be less than 1. Multiplying the increase / decrease ratio of the 35th azimuth channel (= about 0.3), the increase / decrease ratio of the 36th azimuth channel (= about 0.2) and the increase / decrease ratio of the first azimuth channel (= about 0.99). Is calculated as the total increase / decrease ratio of the second azimuth channel, which is the next azimuth channel after the first azimuth channel (= about 0.06).

  Specifically, the S / N detection processing unit 3 is configured such that the first target azimuth channel is the 35th azimuth channel and the second target azimuth channel is the second azimuth channel. The geometric mean (= about 16.8) of the reciprocal of the ratio (= about 16.9) and the total increase / decrease ratio of the second channel (= 0.06) is calculated for the adjacent azimuth channel one level below the 35th azimuth channel. The signal S / N ratio of a certain 34th azimuth channel is calculated.

  The passive sonar signal processing apparatus described above can be realized by hardware, software, or a combination thereof. The passive sonar signal processing method performed by the above passive sonar signal processing apparatus can also be realized by hardware, software, or a combination thereof. Here, “realized by software” means realized by a computer reading and executing a program.

  The program may be stored using various types of non-transitory computer readable media and supplied to the computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Read Only Memory), CD- R, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
Differential processing means for calculating an increase / decrease ratio between the azimuth channels of the signal level;
Integration processing means for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
S / N detection processing means for calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
A passive sonar signal processing apparatus comprising:

(Appendix 2)
The passive sonar signal processing device according to appendix 1,
The passive sonar signal processing apparatus, wherein the differential processing means calculates a ratio between adjacent azimuth channels of the signal level as the increase / decrease ratio.

(Appendix 3)
The passive sonar signal processing device according to appendix 1 or 2,
The integration processing means is included in each section where the increase / decrease ratio continues to be less than 1, for each section where the increase / decrease ratio exceeds 1 and for each section where the increase / decrease ratio is 1. A passive sonar signal processing apparatus, wherein the total increase / decrease ratio for each section is calculated by multiplying the increase / decrease ratios of the azimuth channels.

(Appendix 4)
The passive sonar signal processing device according to any one of appendices 1 to 3,
The S / N detection processing means includes, for each azimuth channel corresponding to the total increase / decrease ratio exceeding 1, one of the total increase / decrease ratio exceeding 1 and the azimuth channel corresponding to the total increase / decrease ratio less than 1. The S / N ratio of the signal is calculated based on the ratio of the total increase / decrease ratio corresponding to the nearest azimuth channel of the azimuth channel corresponding to the total increase / decrease ratio exceeding SNR.

(Appendix 5)
A differential processing step for calculating an increase / decrease ratio between the azimuth channels of the signal level;
An integration processing step for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
An S / N detection processing step of calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
A passive sonar signal processing method characterized by comprising:

(Appendix 6)
The passive sonar signal processing method according to appendix 5,
In the differential processing step, a ratio between adjacent azimuth channels of the signal level is calculated as the increase / decrease ratio.

(Appendix 7)
The passive sonar signal processing method according to appendix 5 or 6,
In the integration processing step, each interval in which the increase / decrease ratio continues to be less than 1, each interval in which the increase / decrease ratio exceeds 1 and each interval in which the increase / decrease ratio is 1 are included in the interval And calculating the total increase / decrease ratio for each section by multiplying the increase / decrease ratios of the azimuth channels.

(Appendix 8)
The passive sonar signal processing method according to any one of appendices 5 to 7,
In the S / N detection processing step, for each azimuth channel corresponding to the total increase / decrease ratio exceeding 1, one of the total increase / decrease ratio exceeding 1 and the azimuth channel corresponding to the total increase / decrease ratio less than 1 The S / N ratio of the signal is calculated based on the ratio of the total increase / decrease ratio corresponding to the nearest azimuth channel of the azimuth channel corresponding to the total increase / decrease ratio exceeding SNR.

(Appendix 9)
A passive sonar signal processing program for causing a computer to function as a passive sonar signal processing device,
Computer
Differential processing means for calculating an increase / decrease ratio between the azimuth channels of the signal level;
Integration processing means for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
S / N detection processing means for calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
Passive sonar signal processing program to function as

(Appendix 10)
A passive sonar signal processing program according to attachment 9, wherein
The differential processing means calculates a ratio between adjacent azimuth channels of the signal level as the increase / decrease ratio, and a passive sonar signal processing program.

(Appendix 11)
A passive sonar signal processing program according to appendix 9 or 10,
The integration processing means is included in each section where the increase / decrease ratio continues to be less than 1, for each section where the increase / decrease ratio exceeds 1 and for each section where the increase / decrease ratio is 1. A passive sonar signal processing program for calculating the total increase / decrease ratio for each section by multiplying the increase / decrease ratios of the azimuth channels.

(Appendix 12)
A passive sonar signal processing program according to any one of appendices 9 to 11,
The S / N detection processing means includes, for each azimuth channel corresponding to the total increase / decrease ratio exceeding 1, one of the total increase / decrease ratio exceeding 1 and the azimuth channel corresponding to the total increase / decrease ratio less than 1. The S / N ratio of the signal is calculated based on a ratio of the total increase / decrease ratio corresponding to the nearest azimuth channel of the azimuth channel corresponding to the total increase / decrease ratio exceeding SNR.

1 differential processing unit 2 one-cross integration processing unit 3 S / N ratio calculation processing unit

Claims (6)

Differential processing means for calculating an increase / decrease ratio between the azimuth channels of the signal level;
Integration processing means for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
S / N detection processing means for calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
A passive sonar signal processing apparatus comprising: The passive sonar signal processing device according to claim 1,
The passive sonar signal processing apparatus, wherein the differential processing means calculates a ratio between adjacent azimuth channels of the signal level as the increase / decrease ratio. The passive sonar signal processing device according to claim 1 or 2,
The integration processing means is included in each section where the increase / decrease ratio continues to be less than 1, for each section where the increase / decrease ratio exceeds 1 and for each section where the increase / decrease ratio is 1. A passive sonar signal processing apparatus, wherein the total increase / decrease ratio for each section is calculated by multiplying the increase / decrease ratios of the azimuth channels. The passive sonar signal processing device according to any one of claims 1 to 3,
The S / N detection processing means includes, for each azimuth channel corresponding to the total increase / decrease ratio exceeding 1, one of the total increase / decrease ratio exceeding 1 and the azimuth channel corresponding to the total increase / decrease ratio less than 1. The S / N ratio of the signal is calculated based on the ratio of the total increase / decrease ratio corresponding to the nearest azimuth channel of the azimuth channel corresponding to the total increase / decrease ratio exceeding SNR. A differential processing step for calculating an increase / decrease ratio between the azimuth channels of the signal level;
An integration processing step for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
An S / N detection processing step of calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
A passive sonar signal processing method characterized by comprising: A passive sonar signal processing program for causing a computer to function as a passive sonar signal processing device,
Computer
Differential processing means for calculating an increase / decrease ratio between the azimuth channels of the signal level;
Integration processing means for calculating a total increase / decrease ratio for each section determined based on the value of the increase / decrease ratio, based on the increase / decrease ratio of the azimuth channel included in the section;
S / N detection processing means for calculating an S / N ratio of the signal based on the total increase / decrease ratio of a plurality of different azimuth channels selected based on the value of the total increase / decrease ratio;
Passive sonar signal processing program to function as

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