JPH11109024A - Frequency analyzer and submersible target sorter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency analyzer and a submersible target sorter processing a submersible target signal having a width in the frequency direction. SOLUTION: A frequency spectral data 101 subjected to frequency analysis at a frequency analyzing section 1 is delivered to an automatic signal detecting section 2 where only the data exceeding a detection threshold level 107 is extracted and outputted as a cluster data 102. A signal profile deciding section 3 sorts the cluster data 102 into a wide signal and a narrow signal. A cluster data determined to be a narrow signal is delivered, as a narrow signal 104 of frequency having a maximum amplitude, to a target sorting section 5. A cluster data determined to be a wide signal is delivered to an average frequency calculating section 4 where the average frequency of the cluster data is calculated and an average frequency data 105 is delivered to the target sorting section 5. The target sorting section 5 collates the narrow signal 104 and the average frequency data 105, as the automatic detection data of the frequency spectral data 101, with a sample frequency data 109 and delivers the data of an estimated submersible data as a target sort data 106 to a display section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency analyzing apparatus and an underwater target classifying apparatus, and more particularly, to a process for automatically classifying an underwater target when signals having a width in a frequency direction in which the underwater target occurs are mixed. The present invention relates to a frequency analysis device and an underwater target classification device corresponding to.

[0002]

2. Description of the Related Art Conventionally, for example, a sound wave having a specific frequency component obtained by receiving a sound wave radiated from an object existing in water is converted into an electric signal by a receiver, and the converted electric signal is Search devices for detecting a specific frequency component, measuring the position of the object, and automatically classifying the object have been put into practical use.

In this kind of automatic classification processing, as shown in FIG. 3, a frequency spectrum exceeding a level threshold is detected from each frequency spectrum obtained by frequency analysis. Then, the detected frequency spectrum is compared with sample frequency data for each underwater target prepared in advance to automatically detect and classify the underwater target. The classification of the underwater target is performed by the operator based on the spectrum information displayed on the display.

[0004]

As described above, the conventional frequency analyzer detects frequency spectrum data having a level equal to or higher than a predetermined threshold as shown in FIG. The underwater target is detected by comparing the spectrum with sample frequency data prepared in advance. In this case, when a narrow signal having a narrow frequency width such as the signal shown in FIG. 3 is received, the frequency spectrum data can be used as it is as the comparison data. However, as shown in FIG. When a target signal is received, multiple frequency spectra are detected during target detection, and the classification of the underwater target becomes uncertain, and the underwater target signal frequency given to the operator is unnecessary. And hinder the operator's determination of the underwater target.

[0005] Therefore, an object of the present invention is to determine the frequency of detected frequency spectrum data, and to more reliably determine the frequency of the detected frequency spectrum data even when the analyzed frequency spectrum data includes a wide signal having a width in the frequency direction. It is an object of the present invention to provide a frequency analysis device and an underwater target classification device capable of detecting an underwater target.

[0006]

In order to solve the above-mentioned problems, a frequency analyzing apparatus and an underwater target classifying apparatus according to the present invention have the following characteristic configurations. (1) frequency analysis means for frequency-analyzing a received signal, and comparison means for extracting frequency data having a level equal to or higher than a predetermined threshold value from an output signal of the frequency analysis means;
Spread determining means for dividing the frequency data obtained by the comparing means into at least one group adjacent on the frequency axis, and obtaining spread in the frequency axis direction of each group;
Compare the spread width determined by the spread determination means with a predetermined width, classifying means to classify into narrow and wide frequency data groups, as the detection frequency of the narrow and wide group classified by the classification means, A detection frequency setting means for setting a frequency determined based on frequency data included in the narrow and wide groups.

(2) The frequency analyzer according to (1), wherein a frequency having a maximum level among frequency data of the group is set as a detection frequency of the narrow group.

(3) The frequency analyzer according to (1) or (2), wherein an average frequency on the frequency axis of the frequency data of the group is set as the detection frequency of the wide group.

(4) An average frequency on the frequency axis obtained by weighting the amplitude of the frequency data of the group is set as the detection frequency of the wide group.
(3) The frequency analyzer.

(5) A classification means for classifying the detected frequency as a target corresponding to the most similar sample data by comparing it with sample data predetermined for each target in advance (1) to (4). Frequency analyzer.

(6) The frequency analyzer according to any one of (1) to (5), wherein the received signal is an underwater acoustic signal received by a passive sonobuoy.

(7) Frequency analysis is performed on the underwater acoustic signal received by the passive sonobuoy to extract frequency spectrum data, and only cluster data, which is frequency spectrum data having an intensity equal to or greater than a threshold value, is extracted. Means for determining whether the width of the cluster data in the frequency direction is narrow or wide; and, when determining that the width of the cluster data in the frequency direction is narrow, detecting the maximum amplitude value of the cluster data and detecting the frequency having the maximum value. Means for extracting the cluster data as a frequency, and when it is determined that the width of the cluster data in the frequency direction is wide, an average frequency is calculated by weighting the amplitude in the cluster data, and the average frequency is calculated as the cluster data. Means for extracting as a frequency, sample frequency data set for each underwater target, and the class Frequency analyzing apparatus characterized by comprising a means for performing classification of targets to compare the frequency of the metadata.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a frequency analyzer and an underwater target classification device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of an underwater target classification device provided with a frequency analysis device according to the present invention.

An underwater target signal received by a passive sonobuoy as a receiver is subjected to an FFT by a frequency analyzer 1.
And the like, and converted into frequency spectrum data 101.

The signal automatic detection section 2 outputs the frequency spectrum data 101 output from the frequency analysis section 1 (FIG. 2A).
From the cluster data 102 (FIG. 2)
(B)). That is, the signal automatic detection unit 2
Compares the amplitude value of the frequency spectrum data 101 output from the frequency analysis unit 1 with the detection threshold 107, and sets the frequency spectrum at the time when the amplitude value falls below the detection threshold 107 as both ends of the cluster data. FIG. 2 (B)
The detection is performed as shown in FIG. Cluster data 10 detected
2 is sent to the signal shape determination unit 3.

The signal shape judging section 3 judges the width in the frequency direction of the cluster data 102 input from the automatic signal detecting section 2. As shown in FIG.
.. An, the frequency corresponding to each amplitude value is f1, f2... Fn, and the constant for determining the frequency width of the cluster data is a frequency width threshold value WT10.
8, the ratio of the sum of the amplitude values A1, A2,... An of the cluster data for each frequency spectrum to the maximum amplitude value Ap of the cluster data is compared with the frequency width threshold value WT108 to obtain the equation (1). The frequency width of the cluster data is determined as follows.

(Equation 1)

When the relationship of the expression (1) is satisfied, the frequency width of the cluster data is defined to be narrow (narrow signal). At this time, the frequency having the maximum amplitude Ap is the narrow signal 10
4 is sent to the target classification section 5. On the other hand, when the relationship of the expression (1) is not satisfied, that is, when the left side is larger than the frequency width threshold value WT108, the frequency width of the cluster data is defined as wide (wide signal), and the cluster data 102 is wide. The signal 103 is sent to the average frequency calculation unit 4 as a signal 103.

The average frequency calculator 4 calculates the amplitude value A of each frequency spectrum data from the input wide signal 103.
The frequency center of the wide signal 103 is obtained by dividing the sum of the amplitude values and the sum of the results obtained by multiplying the amplitude values by 1, A2... An as the frequency weights of the respective frequency spectrum data. If this is set to the average frequency fv, it will be like the formula (2).

(Equation 2)

The average frequency fv of the wide signal 103 calculated using the amplitude value of each frequency spectrum data as a weight is obtained from the equation (2).
Is output to the target classification unit 5.

The target classification unit 5 compares the narrow signal 104 and the average frequency data 105 with the sample frequency data 109 as automatic detection data of the frequency spectrum data 101, and uses the determined underwater target data as the target classification data 10
6 and output to the display unit 6 for display.

[0022]

As described above, the frequency analyzing apparatus and the underwater target classifying apparatus according to the present invention determine the width in the frequency axis direction of frequency data having a level higher than a predetermined level.
It is determined whether the obtained frequency width is narrow or wide.If it is determined to be narrow, for example, the maximum level is set to the detection frequency, and if it is determined to be wide, for example, the average frequency is set to the detection frequency, and the obtained detection is performed. Classification is performed by comparing and comparing the frequency with the predetermined sample frequency, so even if a wide signal with a width in the frequency direction is mixed with the narrow signal in the frequency spectrum data of the underwater target, the underwater target is reliable. Can be categorized.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of an underwater target classification device to which a frequency analysis device according to the present invention is applied.

FIG. 2 is an operation explanatory diagram of the embodiment shown in FIG. 1;

FIG. 3 is a diagram for explaining the operation of a conventional frequency analyzer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frequency analysis part 2 Automatic signal detection part 3 Signal shape judgment part 4 Average frequency calculation part 5 Target classification part 6 Display part 101 Frequency spectrum data 102 Cluster data 103 Wide signal 104 Narrow signal 105 Average frequency data 106 Target classification data 107 Detect Threshold 108 Frequency width threshold 109 Sample frequency data

Claims (7)

[Claims] 1. A frequency analysis means for frequency-analyzing a received signal; a comparison means for extracting frequency data having a level equal to or higher than a predetermined threshold value from an output signal of the frequency analysis means; Spread data divided into at least one group adjacent on the frequency axis in the frequency data, and a spread determining means for obtaining spread in the frequency axis direction of each group, and comparing the spread width obtained by the spread determining means with a predetermined width. Classifying means for classifying into narrow and wide group frequency data; and frequencies determined based on frequency data included in the narrow and wide groups, respectively, as narrow and wide group detection frequencies classified by the classifying means. And a detection frequency setting means for setting a frequency. 2. The detection frequency of the narrow group:
The frequency analyzer according to claim 1, wherein a frequency having a maximum level among the frequency data of the group is set. 3. The detection frequency of the wide group,
The frequency analyzer according to claim 1, wherein an average frequency on a frequency axis of the frequency data of the group is set. 4. The detection frequency of the wide group,
The frequency analyzer according to claim 1, wherein an average frequency on a frequency axis obtained by weighting the amplitude of the frequency data of the group is set. 5. A classifying means for classifying the detected frequency as a target corresponding to the most similar sample data by comparing it with sample data predetermined for each target.
5. The frequency analyzer according to any one of items 1 to 4. 6. The frequency analyzer according to claim 1, wherein the received signal is an underwater acoustic signal received by a passive sonobuoy. 7. A frequency analysis of an underwater acoustic signal received by a passive sonobuoy to extract frequency spectrum data,
Means for extracting only cluster data that is frequency spectrum data having an intensity equal to or greater than the threshold value, and determining whether the width of each cluster data in the frequency direction is narrow or wide; When it is determined to be narrow, the maximum amplitude value of the cluster data is detected, and a frequency having the maximum value is extracted as the frequency of the cluster data.If the width in the frequency direction of the cluster data is determined to be wide, An average frequency is calculated by weighting the amplitude in the cluster data, and a means for extracting the average frequency as the frequency of the cluster data is compared with the sample frequency data set for each underwater target and the frequency of the cluster data. Means for classifying a target.