JP3529670B2 - Underwater target specification analyzer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention analyzes the time change of the receiving frequency of a sound wave emitted by a running body (also referred to as a target) traveling in water to determine the frequency (target frequency) of the generated sound wave and the target. It belongs to the technical field of analyzing target specifications such as speed, target depth, closest approach distance, and closest approach time.

[0002]

2. Description of the Related Art When there is a target that is moving at a constant frequency in water while emitting a sound wave of a constant frequency, this sound wave is received by a sound wave receiver provided in the water and the frequency is analyzed by time-frequency analysis. A frequency analysis phenomenon due to the Doppler effect is confirmed when analyzed with a vessel. That is, the frequency becomes a certain constant value g ₁ (starting frequency) as approaching from a distance.
Gradually decreases from the
Thereafter, as the distance increases, the degree of decrease gradually decreases and approaches a certain value g ₂ (end frequency).
This is illustrated in FIG. 7. Conventionally, the received frequency change as shown in FIG. 7 is drawn on the recording paper, or is drawn on the screen of an electronic display means (for example, a cathode ray tube display device or a liquid crystal display device). The values of the start frequency g ₁ , the end frequency g ₂ and the maximum rate of change K of the frequency and their times are read by a ruler or, in the case of an electronic display means, a cursor operation by a GUI or the like, and these values are used as input data. , The target specifications such as the closest approach time, the target speed, the closest approach distance, and the target frequency are calculated.

Further, the sound wave propagation path from the target to the sound wave receiver, which is performing constant velocity linear motion in the water near the sound wave receiver at a constant depth while transmitting sound waves of many different frequencies,
If there are two paths, a direct propagation path and a reflection propagation path that is reached by being reflected on the water surface, sound waves with a frequency such that the difference between these two paths becomes an integral multiple of the wavelength are mutually strengthened to form a strong signal. Received. The number of such frequencies is not limited to one, and theoretically, a plurality of such frequencies are possible, and therefore, a plurality of frequencies out of a large number of frequencies transmitted by the target are simultaneously strengthened. When such a received signal is analyzed by the time-frequency spectrum analyzer and displayed on the coordinates consisting of the time axis and the frequency axis, frequency interference fringes as shown in FIG. 8 are observed.

Conventionally, the frequency changes appearing in stripes as shown in FIG. 8 are drawn on the recording paper, or on the screen of the electronic display means. In the case of the expression display means, the frequency of the apex of each curve (intersection with the G (T) line in the figure) and the interval of the apex (this is equal to the frequency and the frequency interval at the closest approach time) by operating the cursor with a GUI or the like. Further, the frequency G _n (t) at the arbitrary time T is read, and using these as input data, target specifications such as the closest approach time, the closest approach distance, the target speed, and the target depth are calculated.

[0005]

However, the actual observation diagrams drawn by the analysis of the received signal as described above are not clear as in FIGS. 7 and 8, and there are fluctuations and clear curves. Since it is not a straight line and is blurred (called diffusion), the contrast of light and shade in the image is poor, and it is affected by noise, the measured value itself read by a ruler or a cursor contains a large amount of error. There is also no means for confirming whether or not an actual observation map would be obtained if an image was drawn based on the read measured values. After all, there is a problem that there is a high probability that a measurement value that causes calculation of unrealistic target specifications is read. The root of the above problem is that only a part of the information on the screen of the frequency change obtained by the actual received signal is used, and the whole information related to the aspect of the frequency change is not used. .

In view of the above-mentioned problems of the prior art, an object of the present invention is to display an actual observation diagram (frequency curve) by the frequency or frequency spectrum of the received signal on the electronic image display means as in the conventional case. Set the expected speed, expected depth, expected frequency, expected closest approach time, expected closest approach distance, and estimated underwater sound velocity of a constant-velocity linear motion target, and receive sound waves from a target having such specifications. Then, theoretically calculate what kind of image is obtained, display this predicted value theoretical image (frequency curve) so as to overlap with the actual observed image on the electronic image display means, and observe the screen. However, so that the predicted value theoretical image agrees with the actual observed image, the above-mentioned expected value increase / decrease adjustments are repeated, and the value of each expected value when it is thought that they agree on the whole Hands that are the values of specifications To provide a water target specifications analyzer provided with the.

[0007]

In order to achieve the above object, the present invention has the following means configuration. First, a first aspect of the present invention is an underwater target parameter analysis device including the following means. (B) Sound wave receiver installed in water (b) Frequency of sound wave emitted by a sound wave receiver emitted from a target that is moving at a constant velocity in the water near the sound wave receiver while emitting sound waves of a constant frequency Time-frequency analysis means (c) for analyzing the change corresponding to the passage of time of the received signal image memory for recording the frequency change of the received signal corresponding to the passage of time as a curve image on the time-frequency coordinate ( D) Drawing means (e) for drawing the frequency change corresponding to the passage of time analyzed by the time-frequency analysis means on the time-versus-frequency coordinates of the received signal image memory, the assumed target velocity of the assumed constant velocity linear motion target, Input value varying means capable of changing the input values of the assumed transmission frequency, the assumed closest approach time, the assumed closest approach distance, and the assumed underwater sound velocity (f) Input value display means (g) for displaying the respective input values etc When the target speed, transmission frequency, closest approach time, closest approach distance, and underwater sound velocity of the linear motion target are assumed and set, the assumed frequency that will be received by the sound wave receiver is calculated in correspondence with the passage of time. Assumed theoretical observation value calculation means (h) Theoretical observation value image memory for recording the frequency change of the theoretical observation value with time as a curve image on the coordinate of time vs. frequency (i) For the passage of time of the theoretical observation value Drawing means for drawing the corresponding frequency change on the time-frequency coordinates of the theoretical observation value image memory (n) Image superimposing process for superimposing the image on the received signal image memory and the image on the theoretical observation value image memory Means (L) Electronic image display means for displaying the superimposed images

Next, a second invention is an underwater target parameter analyzing device comprising the following means. (B) Sound wave receiver installed in water (b) Sound wave receiver emits sound waves of many different frequencies and is emitted from a target that is moving at a constant depth in water near the sound wave receiver at a constant speed. Time-frequency spectrum analysis means for analyzing changes in the frequency spectrum of the received sound wave over time (c) Recording changes in the frequency spectrum of the received signal over time as a curve image on time-frequency coordinates A received signal image memory (d) for drawing a drawing means (e) which draws a frequency spectrum change corresponding to the passage of time analyzed by the time frequency spectrum analysis means on the time-frequency coordinate of the received signal image memory. Assuming the target speed, target depth, target closest distance, target closest time, sonic receiver depth and target underwater sound velocity Input value variable means (f) capable of changing the input value display means for displaying the input values (g), based on the assumed input values, a linear distance from the constant velocity linear motion target to the sound wave receiver, Assumed theoretical observation value calculation means (h) for calculating the time change in reception at the sound wave receiver at multiple frequencies whose difference from the distance at which the sound wave is reflected by the water surface and reaches the sound wave receiver is an integer multiple of the wavelength Theoretical observation value image memory for recording the frequency spectrum change of the theoretical observation value over time as an image on the coordinate of time versus frequency (i) The calculated change of the frequency spectrum corresponding to the passage of time Drawing means for drawing on the time-versus-frequency coordinates of the observation value image memory (n) Image superimposing processing means (l) for superimposing the image of the received signal image memory and the image on the theoretical observation value image memory Electronic image display means for displaying the superimposed image

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention include at least a sound wave receiver similar to a conventional underwater target parameter analyzer,
A time-frequency analysis unit (or time-frequency spectrum analysis unit), a received signal image memory, a drawing unit, and an electronic image display unit are provided, and an assumed target velocity, an assumed target depth, an assumed target frequency of an assumed constant velocity linear motion target are provided. , Input closest variable such as estimated closest distance, estimated closest time, and estimated underwater sound velocity, sound wave receiver depth, etc., and input value changing means that can change this input value, and this input value If it is assumed that there is an input display means for displaying and a target having a constant speed linear motion having the above-mentioned main specification values,
Assuming theoretical observation value calculation means for theoretically calculating the frequency or frequency spectrum of the sound wave that will be received by the sound wave receiver, and this theoretical observation value is imaged in the same way as for the actual received signal. An image to be displayed on the electronic image display means by superposing the image on the received signal image memory and the image on the theoretical observation image memory, the theoretical observation value image memory for recording, the drawing means on this memory A superimposing processing means is provided, and the method of using the superimposing processing means is to increase or decrease the main specification values by the input value varying means so that the curve image based on the theoretical observation value is matched with the curve image based on the actual received signal. The main specification value at the time of coincidence is read from the input value display means, and this value is used as the actual target main specification value.

Now, as shown in FIG. 9 for the first invention.
The target 12 is close to the sound wave receiver 7 fixedly installed in the water.
By the constant frequency f_MRight at speed V while transmitting the sound wave of
When moving in a straight line at a constant speed, it is received by the sound wave receiver 7.
How the frequency of sound waves changes over time
Let's take a look. In FIG. 9, t indicates the movement of the target.
Represents the time of day, P₀From the sound wave receiver 7
It is the intersection with the normal line drawn to the
The closest position is shown. t₀Target 12 is the closest
Position P₀Is the time when I came to X (t ₀) Is the closest
Indicates the distance. V (t-t₀) Is target 12 at time t
Position and closest position P₀Indicates the distance between. (T-t
₀) Indicates that the target 12 is the closest position P₀When it is to the left of
Is negative and positive when on the right. X (t) is at time t
The distance between the position of the target 12 and the sound wave receiver 7
Is a function of time t since the target 12 moves. t
Is the time about the movement of the target 12 as described above.
From the target 12 to the sound wave receiver 7 at the time t
For the propagation time required to reach the point, let C be the speed of sound in the water.
For example, X (t) / C from the above. Therefore, the eyes
The sound wave emitted by the mark 12 at time t is received by the sound wave receiver 7.
The time T to be turned is as shown in Formula 1.

[0011]

[Equation 1]

In FIG. 9, when the target 12 moves rightward on the course, X (t) naturally changes, so that the target 12 has a relative speed with respect to the sound wave receiver 7. Therefore, this relative speed is represented by V _m . In this relative velocity, V _m is represented by the time derivative of X (t). Therefore, first, X (t) is obtained. Since X (t) is the hypotenuse of a right-angled triangle that connects the target position at time t, the closest position P _0, and the position of the sound wave receiver 7, X (t) can be calculated according to the Pythagorean theorem by Equation 2. expressed.

[0013]

[Equation 2]

When this X (t) is differentiated at time t, the relative velocity V _m is obtained as shown in equation 3.

[0015]

[Equation 3]

On the other hand, when the target 12 moves and the relative velocity V _m exists between the target 12 and the sound wave receiver 7, the Doppler phenomenon occurs. Now, if the relative speed is V _m (negative when approaching, positive when moving away), the frequency of the emitted sound of the target 12 (target frequency) is f _M , and the underwater sound velocity is C, the Doppler effect causes The frequency of the dial tone is as shown by f (t) in the following Expression 4.

[0017]

[Equation 4]

[0018] The so Equation 5 by substituting _{V m} of Equation 3 to _{V m} of Equation 4.

[0019]

[Equation 5]

That is, this undergoes the Doppler effect,
It is the frequency of the dial tone of the moving target 12 at time t. If a sound wave of this frequency is received by the sound wave receiver 7 at time T shown in Formula 1, what frequency is at time T is t from time T.
Is calculated back to obtain the frequency f (t) at the time t. Therefore, by substituting X (t) in Equation 2 into X (t) in Equation 1 showing the relationship between T and t, the following Equation 6 is obtained.
When a solution for t is obtained from the above, a function h (T) of T is obtained as in the following Expression 7.

[0021]

[Equation 6]

[0022]

[Equation 7]

By substituting this t, that is, h (T) into t of the equation 5, the sound wave frequency g (T) received by the sound wave receiver at the time T can be obtained. That is, Equation 8 is established.

[0024]

G (T) = f (t) = f (h (T))

After all, the received sound wave frequency g (T) at the sound wave receiver at the time T is the transmitted sound frequency f _M of the target 12, the target speed V, the closest approach time t ₀ , and the closest approach distance X (t.
₀ ) and the underwater sound velocity C as parameters, and is expressed as a function g (T) of the time T. Therefore, the change of the frequency g (T) with respect to the passage of the time T can be obtained by performing the calculation of Expression 8 by the assumed theoretical observation value calculation means. By drawing the frequency change of the theoretical observation value thus obtained with time with the drawing means on the coordinate of time versus frequency on the theoretical observation value image memory,
A curved line image similar to the curved line image based on the actual received signal of is obtained. This curve and the curve based on the actual received sound wave in the received signal image memory are displayed on the screen of the electronic image display means by the image superimposition processing means so as to be superimposed, and the curve based on the theoretical observation value is actually received. Input of the target frequency f _M , the target speed V, the closest approach time t ₀ , the closest approach distance X (t ₀ ) and the underwater sound velocity C as assumed values by the input value varying means so as to match the curve based on the wave sound waves. Increase or decrease the value. Of these, the underwater sound velocity C is basically a fixed physical quantity and increases or decreases within a range that can change depending on temperature and other conditions. In this way, the values of the target frequency f _M , the target velocity V, the closest approach time t _0, and the closest approach distance X (t ₀ ) when the curve based on the theoretical observation value exactly matches the curve based on the actual received signal are input. It is read from the value display means, and this is judged to be the main specification value of the target.

Next, the second invention will be described. In the second invention, unlike the first invention, the following two points are premised. The first is that the sound wave emitted from the target that moves in a straight line in water at a constant speed is not one frequency but simultaneously emits sound waves of different frequencies. The second is that the propagation path of the sound wave is from the target to the sound wave receiver. In addition to the direct propagation path to the sound wave, there is a reflection propagation path that is reflected by the sea surface and then reaches the sound wave receiver. Sound waves with a frequency at which the difference between the two propagation path lengths is an integral multiple of the wavelength is received by the sound wave. This means that sound waves having a frequency that strengthens each other when they are received by the receiver and has a difference in the two propagation path lengths that is an odd multiple of a half wavelength weaken each other when received by the sound receiver. Of these, the received signals received constructively are analyzed by the time-frequency spectrum analyzer, and the constructive frequencies are displayed at the coordinates where the time axis and the frequency axis are orthogonal to each other. The image is observed.

Therefore, when the sound wave receiver 7 is installed at a point of the depth h in the water and the target 12 that moves in a constant speed linear motion at a constant depth exists in the vicinity thereof, the installation point of the sound wave receiver 7, FIG. 10A shows the positional relationship on a plane including the straight line along which the target moves, and FIG. 10B shows the installation point of the sound wave receiver 7 and the positions of the vertical plane and the water surface including the target position at time t. Show the relationship. 9A is the same as FIG. 9 except that the depth of the target 12 is constant. In FIGS. 10A and 10B, the direct propagation path length from the target 12 to the sound wave receiver 7 is X (t). On the other hand, the reflection propagation path length Y (t) that reaches the sound wave receiver 7 after being reflected on the water surface once is the sum of Y ₁ (t) and Y ₂ (t) shown in (b).
That is, Y (t) = Y ₁ (t) + Y ₂ (t). When the sound waves are received by the sound wave receiver 7, the fact that the sound waves strengthen each other means that the difference Y between the direct propagation path length X (t) and the reflection propagation path length Y (t).
That is, (t) -X (t) is an integer (n) times the wavelength of the sound wave. Let F _n (t) be the frequency of the sound wave that is multiplied by n, and let the underwater sound velocity be C.
Then, the wavelength is C / F _n (t). Since n times this wavelength is the difference in the propagation path length, the following formula 9 is established.

[0028]

[Equation 9]

Therefore, F _n (t) is given by the following formula 10.

[0030]

[Equation 10]

First, as in the case of FIG. 10A to FIG. 9, the equation 2 is established. Regarding the reflection propagation path length Y (t), if the shortest distance at the closest approach time t ₀ is Y (t ₀ ), the following formula 11 is established.

[0032]

[Equation 11]

On the other hand, from FIG. 10B, the following equations 12 and 13 are established by the Pythagorean theorem.

[0034]

## EQU12 ## Y ² (t) = (D _R + D _T ) ² + D ² (t)

[0035]

X ² (t) = (D _R −D _T ) ² + D ² (t)

Subtracting Equation 13 from Equation 12 gives
The following Expression 14 is obtained.

[0037]

## EQU14 ## Y ² (t) -X ² (t) = 4D _R D _T

Therefore, at the closest time t ₀ , the following equation 15 is obtained.

[0039]

[Equation 15] Y^Two(T₀) -X^Two(T₀) = 4D_RD_T ∴Y^Two(T₀) = X^Two(T₀) + 4D_RD_T

[0040] ^{Y 2} of ^Y 2 _{(t 0)} the formula 11 of the formula 15
Substituting for (t ₀ ) yields Y (t) as in Equation 16.

[0041]

[Equation 16]

Next, Y is added to the denominator and the numerator on the right side of Expression 10.
Multiplying by (t) + X (t) yields Equation 17.

[0043]

[Equation 17]

Substituting equation 14 into the denominator of equation 17,
Substituting Equation 2 into X (t) of the numerator and Equation 1 into Y (t)
Substituting 6 gives F (t) as in Eq.

[0045]

[Equation 18]

That is, when the sound wave is received by the sound wave receiver 7, the mutually strengthening target sound wave frequency F _n (t) has a target velocity V and a target depth D.
_It is expressed as a function of time t, with _{T 1} , the closest time t ₀ , the closest distance X (t ₀ ), the sound receiver depth D _R and the underwater sound velocity C as parameters. The sound wave of the target frequency F _n (t) shown in Expression 18 is emitted at time t, and the time T when the sound wave is received by the sound wave receiver 7 is shown in Expression 6. Formula 6
Equation 7 is a solution of t to t as a function h (T) of T. Therefore, by substituting t in Equation 7 into Equation 18, the sound wave frequency G _n at the sound wave receiver 7 at time T is calculated. (T) can be obtained. That is, Equation 19 is established.

[0047]

G _n (T) = F _n (t) = F _n (h (T))

As described above, at time T,
In the sound wave receiver 7, the frequency G _n (T) of the sound wave in which the direct propagating wave and the reflected propagating wave are intensified is, as shown in Expression 18 and Expression 19, the target velocity V, the target depth D _T , and the closest time t. ₀ , the closest distance X (t ₀ ), the sound wave receiver depth D _R, and the underwater sound velocity C as a function of the time T. Therefore, the change of the frequency G _n (T) with respect to the passage of the time T can be obtained by performing the calculation of the mathematical formula 19 by the assumed theoretical observation value calculation means.

By drawing the frequency change of the theoretical observation value thus obtained with time with the drawing means on the coordinate of time versus frequency on the theoretical observation value image memory,
A curved line image similar to the curved line image based on the actual received signal is obtained. This curve and the curve based on the actual received sound wave in the received signal image memory are displayed on the screen of the electronic image display means by the image superposition processing means in an overlapping manner, and the curve based on the theoretical observation value is the actual The target value V, the target depth D _T , the closest approach time T ₀ , the closest approach distance X (t ₀ ), and the underwater sound velocity C, which are assumed values, are adjusted by the input value varying means so as to match the curve based on the received sound waves. Increase or decrease the input value. Of these, the underwater sound velocity C is basically a fixed physical quantity, and increases or decreases within a range that can change depending on temperature and other conditions.

[0050] Furthermore, wave receiver depth D _R is set to the same depth value as the depth at the time of receiving the actual waves. Thus, the target velocity V, the target depth D _T , the closest approach time T ₀ and the closest approach distance X (t ₀ ) when the curve based on the theoretical observation value matches the curve based on the actual received sound wave are input from the input value display means. Read and judge this as the main specification value of the target.

Although the first and second aspects of the invention have been separately described above, the first and second aspects of the invention have been described.
A device-implemented form is also possible. The means configuration in that case is the same as the configuration of the first invention described in the problem solving means, but in (b), (e), (f) and (g), This can be realized by having a configuration that also has the functions of (e), (f), and (g).

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an underwater target parameter analyzing apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration block diagram common to the first embodiment of the invention and the second embodiment of the invention. In the figure, a sound wave receiver 7, a time frequency (or time frequency spectrum) analyzing means 8, a drawing means 9, a received signal image memory 10 and an electronic image displaying means 11 are included in a conventional underwater target parameter analyzing device. With the same configuration as the configuration, when there is a target performing constant velocity linear motion in the water in the vicinity of the sound wave receiver 7 while emitting a sound wave of a constant frequency, this sound wave is received and the received signal image is received. A time-frequency curve as shown in FIG. 7 is drawn on the time-frequency coordinates on the memory 10, and this curve image is displayed on the electronic image display means 1.
Display on the screen of 1. Further, when there is a target that performs constant velocity linear motion in the water near the sound wave receiver 7 while emitting sound waves of many different frequencies, this sound wave is received and stored on the received signal image memory 10. A striped time-frequency curve as shown in FIG. 8 is drawn on the time-frequency coordinate, and this curve image is displayed on the screen of the electronic image display means 11.

In the first aspect of the invention, the assumed theoretical observed value calculation means 3 is provided with the assumed values of the target velocity V and the target frequency f.
_M , the closest approach time t ₀ , the closest approach distance X (T ₀ ) and the underwater sound velocity C are input, and these input values can be increased or decreased by the input value varying means 2 and are actually input. The respective values are displayed on the input value display means 1. Assumed theoretical observation value calculation means 3
[Mathematical formula-see original document] calculates and outputs the theoretical observation frequency g (T) with respect to the reception time (observation time) T by changing the T according to Expression 8. This calculation output is drawn by the drawing means 4 on the coordinate of the time T vs. frequency g (T) in the theoretical observation value image memory 5 as shown in FIG. The shape of this curve is variously changed by changing the target speed V, the target frequency f _M , the closest approach time t ₀ , the closest approach distance X (t ₀ ) and the underwater sound velocity C by the input value varying means 2. Change.

The curve image on the theoretical observation value image memory 5 and the curve image on the received signal image memory 10 thus drawn are superimposed and synthesized by the image superposition processing means 6 and sent to the electronic image display means 11 to display the screen. It is displayed as shown in FIG. The solid line is a curve based on the actual received signal, and the dotted line is a curve based on theoretical observation values. While viewing this screen, the analysis operator increases or decreases the value of each parameter by the input value varying means 2 so that the curve (dotted line) based on the theoretical observed value matches the curve (solid line) based on the actual received signal, The target speed V, the target frequency f _M , the closest approach time t ₀ , and the closest approach time X (t ₀ ) when they match are read from the input value display means 1 and judged to be the specifications of the target received at that time. To do.

FIG. 4 shows a specific example of the operation panel in which the input value varying means 2 and the input value displaying means 1 are integrated. The value of each parameter can be increased / decreased between the upper limit value and the lower limit value by moving the cursor of the slider. Fine adjustment is possible by pressing the fine decrease button and the fine increase button. The currently input value of each parameter is displayed in the current value column. After all, the slider, the slightly decrease button, and the slightly increase button correspond to the input value changing means 2, and the current value column corresponds to the input value display means 1.

In the second aspect of the invention, the assumed theoretical observation value calculating means 3 is provided with the assumed values of the target velocity V, the target depth D _T , the closest approach time t ₀ , the closest approach distance X (t ₀ ), and the sound wave receiver. The depth D _R and the underwater sound velocity C are input, and these input values can be increased / decreased by the input value changing means 2, and the values currently input are displayed on the input value display means 1. It has become. Assumed theoretical observation value calculation means 3 calculates the reception time (observation time) according to Equation 19.
As a theoretical observation frequency for T, G _n (T) is calculated and output while changing T. This calculation output is drawn by the drawing means 4 from the time T of the theoretical observation value image memory 5 to the frequency G.
A curve as shown in FIG. 8 is drawn on the coordinates of _n (T). The shape of this curve is determined by the input value changing means 2 by the target speed V, the target depth D _T , the closest approach time t ₀ , and the closest approach distance X (t.
₀ ), the sound wave receiver depth D _R and the underwater sound velocity C are increased / decreased to be variously changed. Of these, the sound wave receiver depth D _R should be set to the same depth value as the depth at which the sound wave is actually received, and the underwater sound velocity is basically a fixed physical quantity and changes depending on temperature and other conditions. What should be increased / decreased within the obtainable range As described above.

The curve image on the theoretical observation value image memory 5 and the curve image on the received signal image memory 10 thus drawn are superimposed and synthesized by the image superimposition processing means 6 and sent to the electronic image display means 11 to display the screen. It is displayed as shown in FIG. The solid line is a curve based on the actual received signal, and the dotted line is a curve based on theoretical observation values. While viewing this screen, the analysis operator increases or decreases the value of each parameter by the input value varying means 2 so that the curve (dotted line) based on the theoretical observation value matches the curve (solid line) based on the actual received signal. ,
The target value V, the target depth D _T , the closest approach time t _0, and the closest approach distance X (t ₀ ) at the time of coincidence are input value display means 1.
It is judged from the specifications of the target received at that time.

FIG. 5 shows a concrete example of the operation panel in which the input value varying means 2 and the input value displaying means 1 are integrated. The operation and display are the same as in the case of FIG. FIG. 6 shows the first
A specific example of the operation panel when the invention of FIG.

[0059]

As described above, according to the present invention, it is assumed that the target values are assumed, and the target emits a sound wave with such a value value while performing a uniform linear motion near the sound wave receiver. Then, theoretically calculate the frequency of the sound wave that will be received by the sound wave receiver at each time, and draw this as a curve on the time-frequency coordinate, while receiving the actual wave from the actual target. For sound waves to be generated, the frequency or frequency spectrum is analyzed in the same manner as in the past, and it is drawn as a curve on the time-frequency coordinate, both curves are displayed on the same display screen, and the curve based on the theoretical value Try changing various assumed specifications to match the curve of the received signal,
Since the assumed specification values when they match are determined as the target specification values, the start frequency, end frequency, and maximum rate of change of frequency are read from the curve image as shown in FIG. To calculate the target specification values, or read the frequencies of the vertices of each curve and their intervals from the curve group as shown in FIG. 8 and the frequency at an arbitrary time for the focused curve, and use them as data. The present invention makes full use of the information from the entire curve image by the received signal, as compared with the case where the partial read-out data of the curve image obtained is used to calculate the value. Since we are seeking the original, the accuracy of the obtained target specifications is much higher than in the past. In particular, when the curve image due to the actual received signal has fluctuations, the curve is blurred, the contrast of the image is poor, or the noise is strong, it is very difficult to read data from the image in the past. While the target specifications to be calculated become inaccurate or scattered and are uncertain, in the present invention in which the entire curve image is the information source, the degree of being affected by the adverse conditions as described above is extremely low. There is an effect that.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an underwater target parameter analyzer of the present invention.

FIG. 2 is an explanatory diagram in a case where an attempt is made to match a curve based on a theoretical observation value with a curve based on an actual received sound wave on the display screen in the embodiment of the first invention.

FIG. 3 is an explanatory diagram in a case where an attempt is made to match a curve based on a theoretical observation value with a curve based on an actual received sound wave on a display screen in the embodiment of the second invention.

FIG. 4 is a diagram showing a configuration example of a parameter operation panel in the embodiment of the first invention.

FIG. 5 is a diagram showing a configuration example of an operation panel for parameters in an embodiment of the second invention.

FIG. 6 is a diagram showing a configuration example of an operation panel for parameters when the first invention and the second invention are implemented by one device.

FIG. 7 shows a time-frequency variation curve of a sound wave observed by the sound wave receiver when a target emitting a sound wave of a constant frequency makes a uniform linear motion in the vicinity of the sound wave receiver installed in water. FIG.

FIG. 8: A target that emits sound waves of many different frequencies near the sound wave receiver installed in water has a propagation path to the sound wave receiver that is a direct propagation path and a reflection propagation path on the water surface. It is a figure which shows that the change curve of the time versus frequency of the sound wave observed mutually constructively by a sound wave receiver appears as an interference fringe when performing a constant velocity linear motion at a constant depth.

FIG. 9: Analyzes time-frequency changes of the sound wave observed by the sound wave receiver when a target emitting a sound wave of a constant frequency makes a uniform linear motion in the vicinity of the sound wave receiver installed in water. FIG.

FIG. 10: A target that emits sound waves of many different frequencies near the sound wave receiver installed in water has a propagation path to the sound wave receiver that is a direct propagation path and a reflection propagation path on the water surface. FIG. 6 is an explanatory diagram for analyzing a time-frequency change of sound waves that are observed constructively by a sound wave receiver when performing uniform linear motion at a constant depth.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 input value display means 2 input value varying means 3 assumed theoretical observed value calculation means 4 drawing means 5 theoretical observed value image memory 6 image superposition processing means 7 sound wave receiver 8 time frequency analysis means or time frequency spectrum analysis means 9 drawing means 10 Received signal image memory 11 Electronic image display means 12 Target

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Claims (2)

(57) [Claims] 1. An underwater target parameter analyzer comprising the following means. (B) Sound wave receiver installed in water (b) Frequency of sound wave emitted by a sound wave receiver emitted from a target that is moving at a constant velocity in the water near the sound wave receiver while emitting sound waves of a constant frequency Time-frequency analysis means (c) for analyzing the change corresponding to the passage of time of the received signal image memory for recording the frequency change of the received signal corresponding to the passage of time as a curve image on the time-frequency coordinate ( D) Drawing means (e) for drawing the frequency change corresponding to the passage of time analyzed by the time-frequency analysis means on the time-versus-frequency coordinates of the received signal image memory, the assumed target velocity of the assumed constant velocity linear motion target, Input value varying means capable of changing the input values of the assumed transmission frequency, the assumed closest approach time, the assumed closest approach distance, and the assumed underwater sound velocity (f) Input value display means (g) for displaying the respective input values etc When the target speed, transmission frequency, closest approach time, closest approach distance, and underwater sound velocity of the linear motion target are assumed and set, the assumed frequency that will be received by the sound wave receiver is calculated in correspondence with the passage of time. Assumed theoretical observation value calculation means (h) Theoretical observation value image memory for recording the frequency change of the theoretical observation value with time as a curve image on the coordinate of time vs. frequency (i) For the passage of time of the theoretical observation value Drawing means for drawing the corresponding frequency change on the time-frequency coordinates of the theoretical observation value image memory (n) Image superimposing process for superimposing the image on the received signal image memory and the image on the theoretical observation value image memory Means (L) Electronic image display means for displaying the superimposed images 2. An underwater target parameter analyzer comprising the following means. (B) Sound wave receiver installed in water (b) Sound waves are emitted from a target that is performing constant velocity linear motion in the water near the sound wave receiver at a constant depth while transmitting sound waves of many different frequencies. Time-frequency spectrum analysis means for analyzing changes in the frequency spectrum of the received sound wave over time (c) Recording changes in the frequency spectrum of the received signal over time as a curve image on time-frequency coordinates A received signal image memory (d) for drawing a drawing means (e) which draws a frequency spectrum change corresponding to the passage of time analyzed by the time frequency spectrum analysis means on the time-frequency coordinate of the received signal image memory. Input values of assumed target velocity, assumed target depth, assumed closest approach distance, assumed closest approach time, sound wave receiver depth, and assumed underwater sound velocity of constant velocity linear motion target Variable input value changing means (f) Input value display means for displaying each input value (g) Based on each assumed input value, a linear distance from the constant velocity linear motion target to the sound wave receiver, Assumed theoretical observation value calculation means (h) for calculating the time change in reception at the sound wave receiver at multiple frequencies whose difference from the distance at which the sound wave is reflected by the water surface and reaches the sound wave receiver is an integer multiple of the wavelength Theoretical observation value image memory for recording the frequency spectrum change of the theoretical observation value over time as an image on the coordinate of time versus frequency (i) The calculated change of the frequency spectrum corresponding to the passage of time Drawing means for drawing on the time-versus-frequency coordinate of the observation value image memory (n) Image superimposition processing means (l) for superimposing the image of the received signal image memory and the image on the theoretical observation value image memory Electronic image display means for displaying the serial superimposed image