JPH0368887A - Target azimuth detection method of sonar - Google Patents

Abstract

PURPOSE:To improve the workability of an operator by providing a target frequency detection means and initially setting only the first target frequency and an analytical band to the target frequency detection means. CONSTITUTION:Initial target frequency F0 and an analytical band width (f) are set to a target frequency detection circuit 9. The target frequency detection circuit 9 inputs the data of the signal level to each frequency with respect to all of azimuths from a frequency selecting part 5 and supplies the data of frequency F1 max. in level within a + or -f band from center frequency F0 to an azimuth selection part 4 and also renews the initially set center frequency F0 to the first peak detection frequency F1. When the data of the first peak frequency F1 is inputted, the azimuth selection part 4 calculates the display data of an azimuth signal level in the same way as mentioned above and displays the same on an azimuth display device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a sonar target orientation detection method, and more particularly to a sonar target orientation detection method that detects a target orientation while automatically tracking a target frequency.

[Prior Art] FIG. 2 is a block diagram showing the configuration of a conventional sonar device. Reference numeral 1 denotes a sensor section in which, for example, a plurality of N acoustic wave receiving elements are arranged in an array, and each acoustic wave receiving element is The received acoustic signals are converted into electrical signals and output as independent N-channel electrical signals. 2 is a phasing section, N
It outputs a signal obtained by phasing the acoustic human input signal of the channel for each of a plurality of M directions. Here, phasing means, for example, inserting a variable delay element into each of the N-channel human input signals, adjusting the delay time of the variable delay element, and allowing the sound source in the target direction to pass through each acoustic receiving element and variable delay element. Make sure that all output signal arrival times are the same (in other words, make sure that all N channel input signals are in phase)
, is obtained by adding the output signals of each variable delay element. Therefore, by setting the delay time of the variable delay element in advance for each specific direction, an output signal phased in a specific direction can be obtained. Further, the plurality of directions M means, for example, dividing the entire direction 360' into sectors of every 10 degrees, and providing 36 divided directions. In this case, the divided directions may or may not overlap with each other. In other words, even if it is 0''~10@10'~20'', it is 359
' ~ 11''9'' ~ 21''. In 3, the frequency analysis section analyzes each frequency component (spectrum) of the input phased signal for each M direction, and analyzes the signal for each frequency component. Calculate the level.In principle, each frequency component can be obtained by Fourier transforming the input signal.

Reference numeral 4 denotes an azimuth selection section which inputs the signal levels for each of the M azimuths input into the frequency analysis section 3 as is, calculates display data of the signal level for each azimuth, and displays this on the azimuth display 6.
Output to. Furthermore, when the data of the set frequency is entered manually using the keyboard 8, a signal is extracted from the spectrum signal for each of the M directions in the frequency analysis section 3, and only the set frequency components are manually input, and the direction vs. signal level is Calculate the display data for. Reference numeral 5 denotes a frequency selection section, which manually inputs the signals of each frequency component for each of the M directions from the frequency analysis section 3, and generates a signal for each frequency component for all directions (or it may be selected for each specific direction). Level display data is calculated and output to the spectrum display 7. Reference numeral 6 denotes an azimuth indicator, and in this display example, the horizontal axis represents the azimuth, and the vertical axis displays a waveform as a signal level corresponding to the azimuth. 7 is a spectrum display, and in this display example, the horizontal axis represents frequency, and the vertical axis represents a waveform as a signal level corresponding to the frequency. A keyboard 8 is used for inputting data such as specifying a target frequency.

The conventional sonar device is configured as described above, and the acoustic receiving element included in the sensor section 1 receives an environmental acoustic signal that may include an acoustic signal from a target sound source. The N-channel received signals outputted from each acoustic wave receiving element are each phased by a phasing section 2 for each of a plurality of M directions. The signal level is analyzed every time. This frequency analysis result is supplied to the frequency selection section 5. The frequency selection unit 5 displays signals of each frequency component for each of the M directions inputted, with the horizontal axis representing each frequency component for all directions (or a specific direction) and the corresponding signal level representing the vertical axis. The data is calculated and displayed on the spectrum display 7.

Furthermore, since the frequency analysis section 3 directly supplies the input signal levels for each of the M directions to the direction selection section 4, the direction selection section 4 uses the direction as the horizontal axis and the corresponding signal level as the vertical axis. Display data is calculated and displayed on the direction indicator 6. The operator observes the frequency versus signal level waveform displayed on the spectrum display 7, and if the operator detects that the signal level corresponding to the frequency of the target to be detected is above a certain value, he sets this detection frequency using the keyboard 8. , supplies data of the set frequency to the direction selection section 4. The direction selection section 4 inputs a signal in which only the set frequency component is extracted from the signals for each M direction in the frequency analysis section 3, and displays display data of direction versus signal level for this extracted frequency component. It is calculated and output to the direction indicator 6. From the waveform of the direction versus signal level displayed on the direction display 6, the operator recognizes the direction showing the peak waveform as the direction of the target.

[Problem to be Solved by the Invention] In the conventional sonar device as described above, when receiving an acoustic signal from a moving sound source, the frequency of the target shifts due to Doppler shift, etc., so the operator always needs to check the spectrum display. Monitor the target frequency displayed on the screen, and when a shift in the target frequency occurs,
There was a problem in that it was necessary to reset the set frequency using the keyboard, making the operation complicated.

This invention was made to solve this problem, and is an easy-to-operate sonar target that does not require the operator to reset the target frequency even if the target frequency shifts due to movement of the sound source, etc. The purpose is to obtain a direction detection method.

[Means for Solving the Problems] A sonar target direction detection method according to the present invention involves phasing acoustic signals received through a plurality of acoustic wave receiving sensors for each of a plurality of directions, and The sonar detects the direction of the detection target by analyzing the frequency components of each of the plurality of acoustic signals obtained by In the target direction detection method, the acoustic center frequency (B) and the required bandwidth of the detection target are initially set in the target frequency detection means, and the direction of the detection target is determined from the direction corresponding to the peak reception level in the set acoustic frequency band. At the same time as the detection, the target frequency detection means updates the peak detection frequency in the set acoustic frequency band as the acoustic center frequency of the detection target, and performs the next detection at the updated acoustic center frequency of the detection target and the required bandwidth. The procedure for detecting the direction of the target is repeated, and the target frequency detection means always detects the direction of the detection target while tracking the acoustic center frequency of the detection target.

[Operation] In this invention, acoustic signals received through a plurality of acoustic reception sensors are phased in each of a plurality of directions, and the frequency components of each of the phased acoustic signals are analyzed. In the sonar target orientation detection method for detecting the orientation of the detection target from the orientation corresponding to the peak reception level in the acoustic frequency band of the detection target set based on the frequency analysis result, a target frequency detection means is provided, The acoustic center frequency and required bandwidth of the detection target are initially set in the target frequency detection means, and the direction of the detection target is detected from the direction corresponding to the peak reception level in the set acoustic frequency band, and The target frequency detection means updates the peak detection frequency in the set acoustic frequency band as the acoustic center frequency of the detection target, and detects the updated acoustic center frequency of the detection target and the direction of the next detection target in the required bandwidth. By repeating this procedure, the target frequency detection means detects the direction of the detection target while constantly tracking the acoustic center frequency of the detection target.

[Embodiment] FIG. 1 is a diagram illustrating a sonar target direction detection method according to the present invention, and numerals 1 to 8 are the same as those of the conventional device described above. 9 is a target frequency detection circuit according to the present invention.

The operation shown in FIG. 1 will be explained. Similar to the operation explained in FIG. 2, the environmental sound signal including the target sound signal is displayed on the spectrum display 7 via the sensor section 2, the phasing section 2, the frequency analysis section 3, and the frequency selection section 5. While monitoring this displayed frequency versus signal level waveform, the operator determines the initial target frequency F. and analysis bandwidth f data to the target frequency detection circuit 9 using the keyboard 8.
to set. In the conventional example shown in FIG. 2, data on the set target frequency is directly supplied to the azimuth selection section 4, and display data of azimuth versus signal level for the set frequency component is displayed on the azimuth display 6. In contrast, in the present invention, the initial target frequency F. and analysis bandwidth f are set in the target frequency detection circuit 9.

The target frequency detection circuit 9 inputs signal level data for each frequency for all directions (or a specific direction) from the frequency selection section 5, and determines the center frequency F. The maximum level frequency Fl is detected within a band of ±f. Then, the data of the detected peak frequency F1 is supplied to the direction selection section 4, and the initially set center frequency F is supplied.

is updated to the initial peak detection frequency F1.

When the data of the first peak frequency F1 is input, the direction selection section 4 inputs a signal obtained by extracting only the component of the specified peak frequency F1 from the spectrum signal for each M direction in the frequency analysis section 3, Display data of direction versus signal level is calculated in the same manner as described above, and this display data is displayed on the direction display 6. The direction indicating the peak level displayed in this way is recognized as the direction of the detection target.

In addition, the target frequency detection circuit 9 periodically detects the previously detected peak frequency F (n in the previous example).
Based on the analysis bandwidth f with -1) as the center frequency, the current peak frequency F is detected and the update operation is constantly performed to update this newly detected peak frequency F as the center frequency for the next n+1 times. . Therefore, even if the frequency of the target shifts, such as in the case of an acoustic signal from a moving sound source, the shifted peak frequency is automatically tracked, and data on the acoustic center frequency of the target is always supplied to the direction selection unit 4. Ru. Therefore, the operator does not need to reset the target frequency by shifting the target frequency.

[Effects of the Invention] As described above, according to the present invention, if a target frequency detection means is provided and only the first target frequency and analysis band are initially set in this target frequency detection means, the target frequency detection means will automatically operate from then on. The system automatically detects and tracks the target frequency, and automatically switches the target frequency for direction detection even if the target frequency shifts, eliminating the need for the operator to manually set the target frequency and reducing operator work. The effect of improving sex can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a sonar target direction detection method according to the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional sonar device. In the figure, 1 is a sensor section, 2 is a phasing section, 3 is a frequency analysis section, 4 is a direction selection section, 5 is a frequency selection section, 6 is a direction display, 7 is a spectrum display, 8 is a keyboard, and 9 is a This is a target frequency detection circuit.

Claims (1)

[Scope of Claims] Acoustic signals received via a plurality of acoustic reception sensors are phased in each of a plurality of directions, and each frequency component of the plurality of phased acoustic signals is analyzed, In a sonar target direction detection method that detects the direction of the detection target from the direction corresponding to the peak reception level in the acoustic frequency band of the detection target set based on the frequency analysis result, the acoustic center frequency and required band of the detection target are determined. The width is initially set in the target frequency detection means, and the direction of the detection target is detected from the direction corresponding to the peak reception level in the set acoustic frequency band, and the target frequency detection means updating the peak detection frequency in the frequency band as the acoustic center frequency of the detection target, repeating the procedure of detecting the updated acoustic center frequency of the detection target and the direction of the next detection target in the required bandwidth;
A method for detecting a sonar target direction, characterized in that the target frequency detection means always detects the direction of the detection target while tracking the acoustic center frequency of the detection target.