JP3182754B2 - Frequency analysis device and frequency analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency analysis device and a frequency analysis method, and more particularly to a CPA (Closest).
The present invention relates to a frequency analysis apparatus and a frequency analysis method for calculating a frequency change rate for calculating a CPA range which is a distance between a Point of Approach (the closest point of an underwater target to an underwater acoustic sensor) and an underwater acoustic sensor using a slope cursor.

[0002]

2. Description of the Related Art A frequency analyzer for detecting and classifying underwater targets is a commonly used technique. Such a conventional technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-73648.
There is an acoustic signal display device described in the gazette. That is, the prior art includes a frequency analysis device that performs frequency analysis of underwater sound to obtain a signal level for each frequency, and extracts a signal frequency having a signal level equal to or higher than a predetermined level among the obtained signal levels. A data processing device for judging signal frequency groups having the same time change rate in the frequency direction at the same time among the frequencies to be generated from the same target, and emphasizing the determined signal frequency group; and a data processing device. And a display device for displaying the signal frequency group emphasized by. This type of acoustic signal display device analyzes the frequency of an underwater acoustic signal collected by an underwater acoustic sensor such as a passive sonobuoy and displays the analysis result using display means such as a cathode ray tube. The operator analyzes the underwater target based on the display. As a method of displaying the result, a gram display shown in FIG. 4 is usually used. In this gram display, the vertical axis represents time, the horizontal axis represents frequency, and the luminance represents signal strength, and it is possible to measure a temporal change in a frequency analysis result. The operator can use this gram display to
Underwater target specifications can be calculated by inputting data such as frequency measurement or frequency of the underwater target using a cursor. One of the underwater target specifications is the CPA range. This is a function for calculating a distance between an underwater acoustic sensor such as a passive sonobuoy and an underwater target closest approach point (CPA).
FIG. 3 shows the CPA range. As shown in FIG. 3, when the underwater target is moving from left to right at V (knot), the underwater acoustic signal received by the underwater acoustic sensor S such as a passive sonobuoy is CPA (point C in FIG. 3). The sign of the frequency changes after. When the underwater target is approaching the CPA, the frequency of the sound emitted by the underwater target becomes higher due to the Doppler effect (point A), and the frequency changes from the vicinity of point B to C.
At that point, the Doppler frequency becomes zero. That is, when the underwater target passes the point C, the frequency of the signal received by the underwater acoustic sensor S such as a passive sonobuoy becomes equal to the frequency of the sound emitted by the underwater target. After passing through the CPA, the frequency of the underwater acoustic signal decreases, contrary to the above. FIG. 4 shows this frequency change in gram display. FIG. 4 is an example of a gram display. The points A to E in FIG.
It corresponds to each of the passing positions A to E of the underwater target in FIG. Usually, when calculating the CPA range,
From the gram display in FIG.
Point frequency data is input using a cursor or the like. As the input of the frequency data, all five points may be input, but if two points out of the points A and B and B, C and D are known, the calculation becomes possible. FIG. 5 shows an example of a slope cursor display, and FIG. 6 shows a method of calculating the frequency change rate. When inputting the frequency data, the operator moves the cursor to the measurement point and fixes the data using a switch or the like. In this case, the cursor must be moved to the line of the frequency component of the sound emitted by the underwater target while observing the gram display, and the data must be determined at the point. In particular, B, C,
The input of the point D greatly affects the accuracy of the frequency change rate (the slope of the points B, C, and D) required for the CPA range calculation.

[0003]

However, the prior art has the following problems. The first problem is
The value of the frequency change rate greatly changes depending on how to obtain the frequency data, which greatly affects the accuracy of the CPA range. In particular, the intensity of the underwater acoustic signal is weak (S / N (Si
(gnal to Noise Ratio) is bad), there are cases where some frequency lines on the gram display cannot be recognized, and it becomes difficult to input necessary frequency data. The reason is that the frequency data input method at the time of calculating the CPA range is to input at points using the cursor. The second problem is that at the time of calculating the CPA range, it is necessary to input frequency data of at least four points, which imposes a heavy load on the operator. The reason is that at the time of tracking the underwater target, the operator performs an operation such as class identification of the underwater target in addition to the CPA range. Therefore, while observing the frequency line on the gram display, inputting multiple frequency data by operating the switch
The operator load is increased.

The present invention has been made in view of such a problem, and an object of the present invention is to improve the accuracy of inputting the frequency data required for calculating the CPA range to improve the CPA.
As a result, the accuracy of the range calculation is improved, the frequency change rate is input using a slope cursor, thereby reducing the number of conventional frequency data inputs to reduce the load on the operator. Another object of the present invention is to provide a frequency analysis device and a frequency analysis method that enable calculation of a CPA range even when some frequency lines cannot be recognized.

[0005]

The gist of the present invention is to provide a frequency analyzing apparatus for detecting and classifying an underwater target, wherein an underwater acoustic signal collected by an underwater acoustic sensor is converted to a frequency. Means for analyzing, a frequency analysis result of the underwater acoustic signal, a means for horizontal axis: frequency, a vertical axis: time, and a means for displaying the signal strength in gram with luminance, and a frequency change rate which is a frequency change per unit time, A frequency analysis apparatus having means for displaying using a slope cursor, which is a cursor having a straight line having a predetermined length in a frequency direction with a predetermined inclination, is provided. According to a second aspect of the present invention, there is provided an underwater acoustic sensor, comprising: means for increasing a slope angle of the slope cursor at a constant rate for each operation by an operator; and calculating a tangent of the slope angle of the slope cursor. 2. The frequency analysis apparatus according to claim 1, further comprising means for calculating a frequency change rate required for calculating a CPA range that is a distance between a point of closest approach of the underwater target to the underwater acoustic sensor and the underwater target. . According to a third aspect of the present invention, in accordance with a slope cursor operation for calculating a frequency change per unit time, the slope cursor is tilted based on slope data in conjunction with an operation by the operator. The frequency analyzer according to claim 1 or 2, further comprising a slope cursor conversion unit that generates a slope cursor display signal having a slope. According to a fourth aspect of the present invention, there is provided a data input unit for increasing a slope angle of the slope cursor at a predetermined rate every time an operator performs an operation. In the frequency analysis device described in the paragraph. According to another aspect of the present invention, the tangent of the inclination angle of the slope cursor is calculated, and the C tangent is calculated.
The frequency analysis apparatus according to claim 1, further comprising a frequency change rate calculation unit that calculates a frequency change rate for calculating a PA range. Claim 6 of the present invention
The gist of the present invention resides in a frequency analysis device according to claim 3 , further comprising a display unit for displaying the slope cursor based on the slope cursor display signal. The gist of the present invention is characterized in that the slope cursor conversion unit is configured to output the inclination angle of the slope cursor as inclination data to the frequency change rate calculation unit. A frequency analyzer according to claim 3 or 6. The gist of claim 8 of the present invention is a frequency analysis method for detecting an underwater target and classifying the underwater target, wherein a frequency analysis is performed on an underwater acoustic signal collected by an underwater acoustic sensor; The process of displaying the frequency analysis result of the signal on the horizontal axis: frequency, the vertical axis: time, and the intensity of the signal in terms of luminance in grams, and the frequency change rate, which is the frequency change per unit time, are represented by a predetermined length in the frequency direction. A frequency analysis method characterized by having a step of displaying using a slope cursor which is a cursor having a straight line having a predetermined inclination. Further, the gist of the ninth aspect of the present invention is to increase the inclination angle of the slope cursor at a constant rate for each operation by an operator, and to calculate a tangent of the inclination angle of the slope cursor, Is the distance between the point of closest approach of the underwater target and the underwater acoustic sensor
The frequency analysis method according to claim 8, further comprising a step of calculating a frequency change rate required for calculating the range. The gist of claim 10 of the present invention is that, in accordance with a slope cursor operation for calculating a frequency change per unit time, based on slope data relating to a slope of the slope cursor in conjunction with an operation by the operator. 10. The frequency analysis method according to claim 8, further comprising a slope cursor conversion step of generating a slope cursor display signal having a tilted slope. The gist of claim 11 of the present invention is that the method further includes a data input step of increasing a slope angle of the slope cursor at a predetermined rate every time an operator performs an operation. In the frequency analysis method described in the section. Claim 12 of the present invention
The gist according to claim 8, further comprising a frequency change rate calculating step of calculating a tangent of an inclination angle of the slope cursor and calculating a frequency change rate for calculating the CPA range. Lies in frequency analysis method. The gist of claim 13 of the present invention resides in a frequency analysis method according to claim 10 , further comprising a display step of displaying the slope cursor based on the slope cursor display signal. The subject matter of claim 14 of the present invention, the slope cursor conversion step, claim 10, characterized in that it comprises a step of outputting an inclination angle of the slope cursor to the frequency change rate calculating step as the slope data Or the frequency analysis method described in 13.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION
The frequency analyzer according to the second embodiment includes a means for displaying a slope cursor on a display (the display unit 2 and the slope cursor conversion unit 4 in FIG. 1), and a slope of the slope cursor every time the operator operates a switch or the like. Means for increasing the angle at a fixed rate (data input unit 3 in FIG. 1), and means for calculating the tangent of the inclination angle to calculate the frequency change rate required to calculate the CPA range (FIG. 1)
Is characterized by having a frequency change rate calculation unit 5).

On the other hand, the frequency analysis method executed by the frequency analysis apparatus of the first and second embodiments according to the present invention displays a slope cursor on a display together with the frequency analysis result, and displays the frequency change of the frequency analysis result. By adjusting the inclination and the inclination of the slope cursor, the frequency change rate required for the CPA range calculation is calculated. As a result, there is no need to input the frequency data at points by moving the cursor to the frequency analysis result on the display, and the calculation accuracy is improved. The feature is that it is improved. In addition, the use of the slope cursor reduces the number of input frequency data and reduces the load on the operator. The CPA range is calculated even when the signal strength is weak and some frequency lines cannot be recognized on the gram display. The feature is that it becomes possible. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) Hereinafter, the present invention will be described in detail based on an embodiment. FIG. 1 is a block diagram of a frequency analyzer showing a first embodiment to which the present invention is applied when calculating a CPA range, FIG. 3 is a diagram for explaining a CPA range, and FIG. This is an example.
Here, the gram display is a screen for analyzing the frequency of an underwater acoustic signal collected by an underwater acoustic sensor such as a passive sonobuoy, and displaying the analysis result on the horizontal axis: frequency, the vertical axis: time, and the signal intensity in luminance. This is one of display methods.

In FIG. 1, a frequency analysis unit 1 performs a frequency analysis of an input underwater acoustic signal using a means such as FFT, and obtains frequency analysis data 101 (denoted as FD in the figure).
Is output to the display unit 2, and the analysis result is displayed by the gram display shown in FIG. The data input unit 3 inputs a signal of a switch or the like by an operation of an operator and performs a predetermined operation. First, by a normal cursor operation, a cursor signal 102 (indicated as CS in the figure) is output to the display unit 2 by an operator's switch operation or the like, and the cursor is displayed at a predetermined position of the analysis result displayed on the display unit 2. Let it. Further, in order to input Doppler frequency data (denoted as F1 and F2 in the figure) required for CPA calculation by a switch operation of the operator, frequency data based on the cursor position is selected from the frequency data 101, and Doppler data 106 and Doppler data are selected. The data 107 is output to the SOA calculator 6 and the CPA range calculator 7. Next, by operating the slope cursor for calculating the frequency change rate (the degree of frequency change per unit time), the slope cursor (in the frequency direction (horizontal direction)) is interlocked with the operation of the switch or the like performed by the operator. The slope data 103 (denoted by SD in the drawing) relating to the inclination of a straight line having a predetermined inclination to the slope cursor is output to the slope cursor conversion unit 4. The slope cursor conversion unit 4 generates the slope data 10
Generate a slope cursor with a slope based on 3
It is output to the display unit 2 as a slope cursor display signal 109. On the other hand, the inclination angle of the slope cursor is output to the frequency change rate calculation unit 5 as inclination data 104 (denoted as θD in the figure). The frequency change rate calculation unit 5 calculates an arc tangent based on the inclination data 104 and outputs the calculated arc tangent to the SOA calculation unit 6 as a frequency change rate 105 (denoted by FT in the figure). The SOA calculator 6 calculates the frequency change rate 10
5, SOA (Speed) from Doppler data 106 and 107 and underwater sound velocity data 111 (denoted as VW in the figure)
of Advance: an underwater target speed specification) is calculated and output to the CPA range calculator 7 as SOA data 108 (indicated as VT in the figure). The CPA range calculator 7 calculates the SOA data 108, the frequency change rate 105, the Doppler data 106 and 107, and the underwater sound velocity data 11.
The CPA range is calculated from 1 and the range data 110 (shown as RD in the figure) is output to the display unit 2.

Next, the operation of the first embodiment will be described with reference to FIG.
This will be described in detail with reference to FIG. The frequency analysis unit 1 uses the FFT
The frequency of the underwater acoustic signal input is analyzed using, for example, the display unit 2 as frequency data 101 (denoted by FD in the figure).
And outputs it to the data input unit 3. The operation of the data input unit 3 is switched by an operator's switch operation.

In the case of ordinary cursor operation, a cursor signal 102 is output to the display unit 2 in conjunction with an operation of an operator such as a switch, and the cursor is displayed at a predetermined position.
Further, in order to input Doppler frequency data required for CPA calculation by a switch operation of the operator, frequency data based on the cursor position is selected from the frequency data 101, and the Doppler data 106 and the Doppler data 107 are converted into the SOA calculation unit 6 and the CPA. Output to the range calculator 7.

Further, in the case of a slope cursor for calculating the frequency change rate, the slope data 103 relating to the inclination of the slope cursor is output to the slope cursor conversion section 4 in conjunction with the operation of the switch or the like performed by the operator. FIG. 5 is a display example of a slope cursor. here,
As shown in FIG. 5, the slope angle θ of the slope cursor is set to zero (horizontal state) as an initial value, and the slope angle θ is increased by Δθ each time a switch or the like is operated, and is output as slope data 103. Slope cursor converter 4
Generates a line having an inclination angle θ based on the slope data 103 as shown in FIG. 5 and outputs it to the display unit 2 as a slope cursor display signal 109 (denoted as CD in the figure) to display the slope cursor. Do. Meanwhile,
The supplementary angle θD = 90−θ of the inclination angle θ is calculated, and the inclination data 104 is output to the frequency change rate calculation unit 5. The frequency change rate calculation unit 5 calculates a frequency change rate FT (= ΔF / Δ) near CPA (the point of closest approach of the underwater target to the passive sonobuoy).
In order to calculate T), the tangent of the inclination data 104 is calculated and output to the SOA calculation unit 6 as the frequency change rate 105. In the SOA calculation unit 6, the frequency change rate 105,
The SOA calculation data 108 (denoted as SA in the figure), the Doppler data 106 and 107, and the underwater sound velocity data 111 are input, and the speed specification SOA of the underwater target is calculated by the following calculation formula (1).

SOA = VW × (F1−F2) / (2F0) = VW × (F1−F2) / (F1 + F2) Formula (1) where VW: underwater sound speed, F1: Doppler frequency (high band) Side), F2: Doppler frequency (low frequency side), F0: Underwater target sound source frequency (frequency at zero Doppler effect)
It is.

The calculated SOA is the SOA calculation data 1
As 08, it is output to the CPA range calculation unit 7.

The CPA range calculator 7 calculates the frequency change rate 1
05, the Doppler data 106 and 107, the SOA calculation data 108 and the underwater sound velocity data 111 are input, and the CPA range RD is calculated by the following calculation formula (2).

RD = (F0 × SOA ² ) / (VW × FT) = ((F1 + F2) × SOA ² ) / (2 × (VW × FT)) Formula (2)

The calculated CPA range RD is output as range data 110 to the display unit 2 for display.

(Second Embodiment) Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG.
It is a block diagram of one embodiment which calculates acceleration from change of speed data to which the present invention is applied. Referring to FIG.
The speed measured by the speed measuring unit 8 is the speed data 201
(Shown as VT in the figure) and sent to the display unit 9 to display the speed change. Each time the operator operates a switch or the like, the data input unit 10 increases the slope of the slope cursor at a fixed angle, and outputs this as slope data 202 (denoted by SD in the figure) to the slope cursor conversion unit 11. I do. The slope cursor conversion unit 11 generates a slope cursor having a slope based on the slope data 202 and outputs the generated slope cursor to the display unit 9 as a slope cursor display signal 203 (denoted as CD in the figure). On the other hand, the inclination angle of the slope cursor is output to the speed change rate calculation unit 12 as the inclination data θD. The speed change rate calculation unit 12 calculates a tangent based on the inclination data 204. The calculation result is output to the display unit 9 as acceleration data 205 (denoted by AT in the figure), and the acceleration data is displayed.

As described above, according to the first and second embodiments, instead of inputting the frequency data at points by moving the cursor to the analysis result display as in the related art, the inclination of the slope cursor is analyzed. Just by matching the frequency change on the display, the value of the frequency change rate required for the CPA range calculation can be obtained, and even when the signal strength is weak and some frequency lines cannot be recognized on the gram display, Calculation of the CPA range becomes possible. As a result, there is an effect that the value of the frequency change rate required for the CPA range calculation can be obtained with high accuracy.

Further, the present invention solves the problem that the operator has to perform the operation of identifying the type of the underwater target in addition to the CPA range at the time of tracking the underwater target. As a result, the input of the frequency data is reduced to two points, and the input of the frequency change rate can be visually input using the slope cursor. Thereby, there is an effect that the load on the operator can be reduced.

In the present embodiment, the present invention is not limited to the above-described embodiment. The present invention is not limited to the above-mentioned technology, and a technique for performing a frequency change rate for calculating a CPA range using a slope cursor, which is suitable for applying the present invention. Can be applied. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and are suitable numbers for implementing the present invention.
Position, shape, etc. In each drawing, the same components are denoted by the same reference numerals.

[0022]

Since the present invention is configured as described above, the following effects can be obtained. The first effect is CPA
That is, the value of the frequency change rate required for the range calculation can be obtained with high accuracy. The reason for this is that the slope of the slope cursor is made to coincide with the change in the frequency of the analysis result display, instead of having to move the cursor to the analysis result display and inputting the frequency data at points as in the prior art, which is necessary for the CPA range calculation. This is because the value of the frequency change rate can be obtained, and the CPA range can be calculated even when the signal strength is weak and some frequency lines cannot be recognized on the gram display. The second effect is that the load on the operator can be reduced. The reason is that the present invention solves the problem that conventionally the operator had to perform operations such as class identification of the underwater target in addition to the CPA range when tracking the underwater target, and the operation procedure had to be reduced as much as possible. This is because the input of the frequency data is reduced to two points, and the input of the frequency change rate can be visually input using the slope cursor.

[Brief description of the drawings]

FIG. 1 is a block diagram of a frequency analyzer according to a first embodiment to which the present invention is applied when calculating a CPA range.

FIG. 2 is a block diagram of an embodiment for calculating an acceleration from a change in speed data to which the present invention is applied.

FIG. 3 is a diagram for explaining a CPA range.

FIG. 4 is an example of a gram display.

FIG. 5 is an example of a slope cursor display.

FIG. 6 shows a method of calculating a frequency change rate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 frequency analysis unit 2 display unit 3 data input unit 4 slope cursor conversion unit 5 frequency change rate calculation unit 6 SOA calculation unit 7 CPA range calculation unit 8 speed measurement unit 9 display unit 10 data Input unit 11 Slope cursor conversion unit 12 Speed change rate calculation unit 101 Frequency data (FD) 102 Cursor signal (CS) 103 Slope data (SD) 104 Slope data (θD) 105 Frequency change rate (FT) 106: Doppler frequency data (F1) 107: Doppler frequency data (F2) 108: SOA calculation data (SA) 109: Slope cursor display signal (CD) 110: Range data (RD) 111: Underwater sound velocity data (VW) 201 ... speed data (VT) 202 ... slope data (SD) 203 ... slope cursor display No. (CD) 204 ... inclination data (θD) 205 ... acceleration data (AT)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15 / 00-15/96

Claims (14)

(57) [Claims] 1. A frequency analysis device for detecting and classifying an underwater target, comprising: means for frequency-analyzing an underwater acoustic signal collected by an underwater acoustic sensor; Axis: frequency,
Vertical axis: means for displaying time and signal intensity in gram by luminance, and a cursor that gives a predetermined gradient in a frequency direction, which is a frequency change per unit time, to a straight line having a predetermined length in the frequency direction. A frequency analysis device having means for displaying using a slope cursor. 2. A means for increasing the inclination angle of the slope cursor at a constant rate for each operation by an operator, calculating a tangent of the inclination angle of the slope cursor, and determining the closest approach point of the underwater target to the underwater acoustic sensor. The frequency analysis device according to claim 1, further comprising a unit that calculates a frequency change rate necessary for calculating a CPA range that is a distance between the underwater acoustic sensors. 3. A slope cursor display signal having a slope based on slope data on a slope of the slope cursor in response to an operation by the operator in response to a slope cursor operation for calculating a frequency change per unit time. The frequency analysis device according to claim 1, further comprising a slope cursor conversion unit that generates a signal. 4. The frequency analysis device according to claim 1, further comprising a data input unit for increasing a slope angle of the slope cursor at a predetermined rate every time an operator performs an operation. 5. The frequency according to claim 1, further comprising a frequency change rate calculation unit that calculates a tangent of an inclination angle of the slope cursor and calculates a frequency change rate for calculating the CPA range. Analysis equipment. 6. The frequency analysis apparatus according to claim 3 , further comprising a display unit that displays the slope cursor based on the slope cursor display signal. Wherein said slope cursor conversion unit according to claim 3 or 6, characterized in that it is configured to output an inclination angle of the slope cursor to the frequency change rate calculating section as the slope data Frequency analyzer. 8. A frequency analysis method for detecting and categorizing an underwater target, comprising the steps of: performing a frequency analysis of an underwater acoustic signal collected by an underwater acoustic sensor; Axis: frequency,
Vertical axis: a step in which time and signal strength are displayed in gram by luminance, and a frequency change rate, which is a frequency change per unit time, is a cursor that gives a predetermined inclination to a straight line having a predetermined length in the frequency direction. A frequency analysis method comprising a step of displaying using a slope cursor. 9. A step of increasing the inclination angle of the slope cursor at a constant rate for each operation by an operator; calculating a tangent of the inclination angle of the slope cursor; The frequency analysis method according to claim 8, further comprising a step of calculating a frequency change rate necessary for calculating a CPA range that is a distance between the underwater acoustic sensors. 10. A slope cursor display signal having a slope based on slope data related to a slope of the slope cursor in response to an operation by the operator in response to a slope cursor operation for calculating a frequency change per unit time. The frequency analysis method according to claim 8, further comprising a slope cursor conversion step of generating a slope cursor. 11. The frequency analysis method according to claim 8, further comprising a data input step of increasing a slope angle of said slope cursor at a predetermined rate every time an operator operates. 12. The frequency according to claim 8, further comprising a frequency change rate calculating step of calculating a tangent of an inclination angle of the slope cursor and calculating a frequency change rate for calculating the CPA range. Analysis method. 13. The frequency analysis method according to claim 10 , further comprising a display step of displaying the slope cursor based on the slope cursor display signal. 14. The frequency analysis method according to claim 10, wherein the slope cursor converting step includes a step of outputting the slope angle of the slope cursor as tilt data to the frequency change rate calculating step. .