JPS62288586A - Acoustic position measuring system - Google Patents

Abstract

PURPOSE:To estimate the depth, the distance and the bearing of a sound source and to perform positional limitation, by arranging a plurality of submerged receivers by utilizing a ship and reading an incident angle to draw a chart to measure the depth and distance of the sound source. CONSTITUTION:A plurality of submerged receivers are arranged by utilizing a ship. When the min. incident angle theta1 or theta4 from above and the min. incident angle theta2 or theta3 from below are calculated with respect to a horizontal reference plane, sea bottom angle-of-reflection theta2 > direct incident angle theta1 is formed in a region I and sea bottom angle-of-reflection theta3 < sea level angle-of-reflection theta4 is formed in a region II and, when it is judged whether an upper side is large or a lower side is large with respect to a horizontal plane in the relation between theta1 and theta2 and that between theta3 and theta4, it is cleared whether a receiving point is present in the region I or the region II with respect to a sound source. When the region is cleared, the position of the sound source of Fig. 2 can be calculated on a chart from the chart in the vicinity of the region and the seasonal sound velocity profile of a sea area on the basis of the aforementioned relation of theta1 and theta2 or theta3 and theta4.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a passive acoustic measurement method for audible positioning of a sound source existing underwater, and particularly relates to a six-dimensional measurement method including the depth of the sound source. This invention relates to a passive acoustic measurement method suitable for

[Background of the invention]

The conventional device is "Marine Sounds J4 Year Acoustics - Fundamentals and Applications - Part 6 Applied Edition Chapter 8 Fukagawa Sound Sources (Passive Usage)" edited by Marine Sound Research Group, pp. 8, 256-243 (1984, 3).
．． As described in Section 4 "Measurement of Underwater Position J (P2S5), in passive acoustic measurements, one set of measurement equipment can only determine the direction of the sound source, and if it is necessary to know the distance, two sets of measurement equipment are required. Or, use more devices to measure the direction from two or more locations, find the intersection, and localize the location.
The method used was a response signal similar to a transponder. Especially when measuring the depth of a sound source,
As described in Publication No. 507, a position localization method that uses depth information from a sound source by transmitting depth information using a pinger, etc. However, some of the targets of passive acoustic positioning include In some cases, the transmitted depth information cannot be used. Under such circumstances, it is extremely difficult to localize the depth of the target sound source. .

On the other hand, there is a characteristic phenomenon related to the propagation of underwater sound waves that has a major influence on this difficulty. Particularly in the sea, it is strongly influenced by water temperature and water pressure, and its propagation characteristics exhibit complex aspects. This example is R,
J. URICK, translated by Akira Tsuchiya; “Principles of Underwater Acoustics J.
Quoted from P 153, Figure 6.14 (Kyoritsu Shuppan KK, published December 1, 1978), and shown in Figure 1F+. As shown in the figure, the propagation form differs depending on the depth of the f source. These complex physical phenomena represent the difficulty of underwater acoustic measurements.

[Purpose of the invention]

An object of the present invention is to provide location localization including the depth of a sound source based on the propagation form of sound waves in the sea, for sound sources for which depth information is not provided.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention detects the phase of the signal between the output sides of the vertically arranged receivers, and
In the liquid, the angle of incidence from above and below the horizontal reference point is the minimum angle of incidence θ8. θ, or θ,·θ4 is determined, and a sound line diagram is drawn based on this to determine the depth and horizontal distance of the unknown sound source S.

[Embodiments of the invention]

As illustrated in Figure 1, the propagation form differs depending on the depth of the sound source, but this will be explained in an easy-to-understand manner using Figure 2, which shows the relationship between the sound source and the receiving point.

Diagram 2 shows sound rays with depth on the vertical axis and distance on the horizontal axis, but among the sound rays that are incident on the receiving point, there are waves that are incident from above (i.e., shallower) than the receiving point. If we focus on the incident waves from below (deeper side), the situation is reversed in areas ■ and ■. In particular, for waves incident on the receiving point, the sound ray with the smallest incident angle among the waves coming from above with respect to the horizontal direction of the receiving point, and the one with the smallest incident angle among the waves coming from below the receiving point. By focusing only on two sound rays with small angles, one above and one above, and using their normal angle of incidence to draw the sound rays based on the nearby chart, it is possible to estimate the depth of the sound source. is possible.

In addition, in the conventional ranging method that calculates the intersection point from the orientation of multiple (minimum 2 points) receiving points in a horizontal plane, the interval between the receiving points is generally short compared to the distance to the target point. It wasn't necessarily good in terms of accuracy. According to the present invention, when drawing a diagram, since the receiving point includes seabed reflection or sea surface reflection, the point between the receiving point and the virtual receiving point reflected in the reflection is regarded as the baseline. Even with one receiving point, the distance calculation accuracy is improved compared to the conventional method.

Based on the method described above, the depth of the sound source is estimated and positioned, but the horizontal direction is also determined.

As exemplified in Reference (1), it can be determined using the conventional method, so when used in conjunction with the conventional method, the depth, distance, and direction of the sound source position can be determined, making it possible to perform true location localization. It is. In the following, description will be given using expressions focusing only on depth.

Hereinafter, one embodiment of the present invention will be explained with reference to Figures 3 to 4. As shown in Figure 3, the underwater receiver uses a ship's belly or the like to arrange a plurality of receivers 1. The normal angle of incidence is determined by correlating the signal outputs of the individual receivers. The minimum angle of incidence θ from above with respect to the horizontal reference plane, or θ4. Determining the minimum angle of incidence θ or θ from below: 1. ? In Figure 2, in region ■, the seafloor reflection angle θ and the direct incidence angle θ.

Therefore, in region (2), the seafloor reflection angle is θ, and the sea surface reflection angle is θ4. The relationship between θ and θ, and the relationship between θ and 04 can be determined by determining whether the upper side or the lower side is larger with respect to the horizontal plane.
It turns out that there is. Once the area is known, the above θ, and θ,
Alternatively, from the relationship between θ and θ4, the position of the sound source in Figure 2 can be found graphically from the nearby nautical chart and the sound speed profile of the sea area depending on the season.

〔Effect of the invention〕

According to the present invention, it is possible to measure the depth and distance of a sound source by arranging a plurality of underwater receivers on the hull of a ship, interpreting the angle of incidence, and plotting, so in passive acoustic position measurement,
It has the effect of estimating the depth, distance and direction of the sound source, and localizing the location.

[Brief explanation of drawings]

,? Figure 1 is an explanatory diagram illustrating the sound wave propagation characteristics when the water depth of the sound source is different, Figure 172 is an explanatory diagram using sound rays for sensing the depth of the sound source according to the present invention, and Figure 3 is an explanatory diagram illustrating the wave receiver. Figure 4 is a block diagram of a system configuration showing one embodiment of the present invention. S...Sound source, P...Receiver array, θ8
．． θ Keeper shooting angle, A, △, ■, ■... sound ray, ■, ~Vn
Vertical output, 81~8m horizontal output, 1... Receiver, 2.
...Input terminal, 3--Amplifier, 4... Beamforming circuit, 5... Beamforming circuit, 6...
Mode detection circuit, 7... Horizontal direction processor, 8... General processor, 9... Display device.

Claims (1)

[Claims] By arranging multiple receivers on the ship's hull, etc., and detecting the phase of the signal between the outputs of the vertically arranged receivers, we can determine the angle of incidence from above and below the horizontal reference point among the incident sound waves. Minimum angle of incidence θ_1, θ_2 or θ_3, θ_4
An acoustic position measurement method characterized by determining the depth and horizontal distance of an unknown sound source S by drawing a sound ray diagram from this.