JPH05119144A - Wide band frequency characteristic signal processing method - Google Patents

Abstract

PURPOSE:To easily specify the azimuth of a target even if the level of an input wide band frequency characteristic signal is very low and to provide display easy to see. CONSTITUTION:A frequency analyzer 2 analyzes the frequency of an input wide band frequency characteristic signal and converts it into data, etc., representing a frequency spectrum. An azimuth calculating part 3 calculates the azimuth of a target for each frequency spectrum from each component of two systems of wide band frequency characteristic signals and sums up for each azimuth. A first statistic part 4 calculates the degree of variation which a spectrum-summed level has from a spectrum average level in all azimuths. A second statistic part 5 calculates the forward and backward azimuths and variation from the past characteristic data for each azimuth with respect to the characteristic data calculated by the first statistic part 4 so that accumulation is done while one of the above is added as a weight. Then a display part 7 displays the results while the horizontal axis is the azimuth and the vertical axis is the inverse of the calculated variation of the second statistic part 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wideband frequency characteristic signal processing method for detecting the direction of a submarine or the like by using an acoustic signal obtained from underwater.

[0002]

2. Description of the Related Art Sound is generated from an object moving underwater. The sound is divided into orthogonal directions such as east-west and north-south and detected by an underwater receiver that can be detected by two systems and detected by each system. The direction in which the target object exists can be calculated from the signal components. The detected signal is
It is a wideband frequency characteristic signal (BBF signal) having a signal component over a wide band.

FIG. 3 shows a structure for processing the wide band frequency characteristic signal of this kind to know the direction of the target object. A solid line with an arrow in the figure shows the flow of control.

In FIG. 3, an input section 11 inputs wideband frequency characteristic signals of two systems from an underwater receiver or the like.

Next, the frequency analysis section 12 frequency-analyzes the input wideband frequency characteristic signal and converts it into a signal or data showing a frequency spectrum. The frequency analysis is performed to facilitate the separation of the signal from the target object and the noise.

Next, the azimuth calculation unit 13 determines, for each frequency spectrum, the target object, which is the source of the signal, from the ratio and polarity of each component of the wideband frequency characteristic signals of the two systems after being converted into the frequency spectrum. Calculate the bearing.

Next, the continuation determination section 14 determines whether or not to continue the process according to an instruction from the outside.

When the process is repeated, the accumulating unit 15 adds the result of that time to the previous result, and shifts to the process of the input unit 11 again.

When the processing is not repeated, the display unit 1
6 displays the result at that time.

FIG. 4 shows an example of the display on the display unit 16, in which the vertical axis represents the azimuth and the horizontal axis represents the frequency, and the collected results are shown by dots.

In FIG. 4, the high dot density 150
The degree indicates the direction of the target object.

[0012]

As described above, in the conventional wideband frequency characteristic signal processing method, noise is removed by frequency analysis. However, as the subsequent processing, the azimuth is simply calculated. Since only the results are accumulated, when the level of the wideband frequency characteristic signal is very small, the background noise disperses the signal from the target object, which makes it difficult to identify the direction.

FIG. 5 shows an example of display when the level of the wide band frequency characteristic signal is very small, and the direction cannot be specified as in the case of FIG.

Further, since the conventional display is "direction" vs. "frequency", it is difficult to see.

The present invention has been proposed in view of the above points, and an object thereof is to make it possible to easily specify the azimuth even when the level of the wideband frequency characteristic signal is minute and to make the display easy to see. It is to provide a wideband frequency characteristic signal processing method capable of performing the above.

[0016]

In order to achieve the above-mentioned object, the present invention provides a frequency analysis section for frequency-analyzing an input wideband frequency characteristic signal and converting it into a signal or data showing a frequency spectrum. The azimuth calculation unit that calculates the azimuth of the target object for each frequency spectrum from each component of the converted wideband frequency characteristic signals of the two systems, and adds up the azimuth for each azimuth, and the spectrum summation level of each azimuth is calculated from the spectrum average level of all azimuths. The first statistic unit that calculates the degree of variation and the characteristic data calculated by the first statistic unit calculates the variation between the front-back azimuth and the past characteristic data for each azimuth, and weights one of them. And a second statistic section for performing cumulative calculation.

In addition to these configurations, the horizontal axis is the azimuth,
A display unit for displaying the result by taking the reciprocal of the variation of the calculation result of the second statistical unit is provided on the vertical axis.

[0018]

In the wideband frequency characteristic signal processing method of the present invention, the input wideband frequency characteristic signal is frequency-analyzed by the frequency analysis unit and converted into a signal or data showing a frequency spectrum, and then converted into a frequency spectrum. Two
The azimuth calculation unit calculates the azimuth of the target object for each frequency spectrum from each component of the wideband frequency characteristic signal of the system and adds the azimuth for each azimuth, and the first statistic unit calculates the spectrum summation level of each azimuth from the spectrum average level of all azimuths. Is calculated, and the second statistic section calculates the variation between the front-back azimuth and the past characteristic data for each azimuth with respect to the characteristic data calculated by the first statistic section. It is added as a weight and then cumulatively calculated. Then, the display unit displays the result by taking the azimuth on the horizontal axis and the reciprocal of the variation of the calculation result of the second statistical unit on the vertical axis.

[0019]

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

FIG. 1 is a block diagram showing an embodiment of a wideband frequency characteristic signal processing system of the present invention. A solid line with an arrow in the figure shows the flow of control.

In FIG. 1, the present embodiment has an input unit 1, and
A frequency analysis unit 2, an azimuth calculation unit 3, a first statistical unit 4,
The second statistics unit 5, the continuation determination unit 6, and the display unit 7 are included. The details of the functions of each unit will be described through the following operations in order to avoid duplication.

The operation of the above embodiment will be described below.

First, the input section 1 inputs the wideband frequency characteristic signals of two systems from the underwater receiver.

Next, the frequency analysis unit 2 frequency-analyzes the input wideband frequency characteristic signal and converts it into a signal or data showing a frequency spectrum. The frequency analysis is performed to facilitate the separation of the signal from the target object and the noise, as described above.

Next, the azimuth calculation unit 3 determines, for each frequency spectrum, the target object, which is a signal generation source, from the ratios and polarities of the respective components of the wideband frequency characteristic signals of the two systems after being converted into the frequency spectrum. Calculate the bearing. The azimuth calculation unit 3 also sums the spectrum levels for each azimuth.

Next, the first statistic unit 4 performs spectrum averaging in all directions, and calculates how much the spectrum summation level in each direction has variation from the average level.

Here, the azimuth of the target object has a small variation. This is because even if there is background noise other than the direction of the target object, the amplitude fluctuates up to negative infinity, which causes large variations, but in the direction of the target object, even if the wideband frequency characteristic signal is small, the amplitude is small. Because does not swing to negative infinity.

Next, the second statistics unit 5 applies the data (characteristic data) calculated by the first statistics unit 4 for each direction.
The variation between the front-rear direction and the past characteristic data is calculated, one of them is added as a weight, and then the cumulative calculation is performed. In addition, to obtain the variation with the characteristic data of the front-back direction,
This is because the azimuth of the target object has a smaller variation and a steeper characteristic can be obtained. Further, the reason why the variation with the past characteristic data is obtained is to reduce the influence of an instantaneous false detection.

Here, the variation with respect to the characteristic data of the front and rear azimuth is taken as the value of the variation of the azimuth by examining the degree of the variation of the peripheral azimuth for several points for each azimuth. Further, the variation between the past characteristic data is obtained by curve fitting the slide correlation result between the characteristic data obtained in the past and the characteristic data obtained at the present time.

Next, the continuation determination section 6 determines whether or not to continue the process according to an instruction from the outside or the like.

When the process is repeated, the process of the input unit 1 is performed again.

When the process is not repeated, the display unit 7
Displays the results at that point.

FIG. 2 shows an example of the display on the display unit 7, in which the horizontal axis represents the azimuth and the vertical axis represents the reciprocal of the variation of the characteristic data in each azimuth, which is the result of the second statistics unit 5. There is.

Since the characteristic data of the azimuth of the target object has a small variation, its reciprocal becomes maximum in the azimuth of the target object and appears as a peak. In FIG. 2, 15
A peak appears near 0 degrees, and this is the direction of the target object.

[0035]

As described above, according to the wideband frequency characteristic signal processing method of the present invention, the dispersion of the spectrum summation level of each azimuth with respect to the spectrum average level of all azimuths, the front and rear azimuths and the past azimuths of each azimuth. Since the variation between the characteristic data and the characteristic data is calculated and added together, the azimuth of the target object can be sufficiently specified even if the wideband frequency characteristic signal is at a minute level, and the recognition accuracy can be improved. is there.

Further, by displaying the result by taking the azimuth on the horizontal axis and the reciprocal of the variation of the characteristic data on the vertical axis, the azimuth of the target object can be expressed as a peak, and the result can be easily recognized. There is also.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a wideband frequency characteristic signal processing system of the present invention.

FIG. 2 is a diagram showing an example of a display.

FIG. 3 is a configuration diagram showing an example of a conventional wideband frequency characteristic signal processing method.

FIG. 4 is a diagram showing an example of a conventional display.

FIG. 5 is a diagram showing an example of a conventional display.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Input part 2 ... Frequency analysis part 3 ... Direction calculation part 4 ... 1st statistics part 5 ... 2nd statistics part 6 ... Continuation determination part 7 ... Display part

Claims (2)

[Claims] 1. A frequency analysis unit for frequency-analyzing an input wideband frequency characteristic signal and converting it into a signal or data showing a frequency spectrum, and a component of each of two systems of wideband frequency characteristic signals converted into frequency spectrum. An azimuth calculation unit that calculates the azimuth of the target object for each frequency spectrum and adds up for each azimuth, and a first statistic unit that calculates how much the spectrum summation level of each azimuth has variations from the spectrum average level of all azimuths. A second statistical unit for calculating a variation between the front-back direction and the past characteristic data for each azimuth with respect to the characteristic data calculated by the first statistic unit, adding one as a weight, and then performing cumulative calculation. A wideband frequency characteristic signal processing method characterized by the above. 2. The wideband frequency characteristic signal according to claim 1, further comprising a display unit for displaying the result by taking the reciprocal of the variation of the calculation result of the second statistical unit on the horizontal axis and the azimuth on the vertical axis. Processing method.