JPH0266481A - Objective position detecting device - Google Patents

Abstract

PURPOSE:To accurately detect an objective position or a moving direction only by three non-directive passive sonobuoys by aiming at the Doppler frequency change of sound generated from an object observed by the three non- directive passive sonobuoys and executing error minimizing processing based upon a Kalman filter. CONSTITUTION:Submarine sounds detected by the three non-directive passive sonobuoys 1 to 3 are sent to a frequency analyzing part 5 mounted on an aircraft through respectively different radio waves such as VHF bands. A sonobuoy position measuring part 4 detects the positions of respective passive sonobuoys to be the originating sources of radio waves by receiving the radio waves sent from the passive sonobuoys 1 to 3 through directive antennas. Three passive buoy signals supplied to a frequency analyzing part 5 are converted from time area data into frequency area data by three channel frequency analyzing circuits corresponding to respective buoys 1 to 3 by means of Fourier transformation or the like and supplied to an objective sound specifying part 6. A Kalman filter part 8 minimizes an error in an objective position and a moving speed momentally sent from a sound source position moving speed calculating part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a target position detection device, and particularly to a target position detection device 1LVC that detects the position of a moving underwater sound source using an omnidirectional sonobuoy.

[Conventional technology]

Conventionally, this type of target position detection device drops a large number of sonobuoys from the aircraft on which the observer is boarding into the search area of Okiichi, receives all deaf people with the sonobuoys, converts them into radio signals, and sends them to the aircraft. , the aircraft receives this and processes it to detect the target. In this case, as a sonobuoy,
They used either active sonobuoys or directional passive sonobuoys.

[Problem to be solved by the invention]

When using the above-mentioned conventional target position detection device, the horn buoy emits a sound to detect the target, so the target detects the sound and retreats to an area where the sound waves cannot reach. It has the disadvantage of being

In addition, the directional passive sonogui must have a structure with multiple directivity for target detection and an omnidirectional microphone for determining the quadrant of the detected target.
The drawback is that the cost becomes excessive in an operational state where a large number of expensive shells are used.

An object of the present invention is to provide a target position detection device capable of detecting a target position using three non-directional sonobuoys, in order to eliminate the above-mentioned drawbacks. The target position detection device of the invention includes three non-directional passive sonoguis deployed in an operational sea area, a sonobuoy position measuring unit that measures the positions of the three passive sonoguis, and a frequency analysis section that analyzes the frequency of the underwater sound signal obtained by the sound source, a target sound identification section that identifies the characteristic sound frequency of the target sound source from the analysis result of the frequency analysis section, and position information of the passive sonogui A sound source position/moving speed calculation unit that calculates the position and moving speed of the sound source from the frequency of the target sound that is being displaced by drag; and a device that minimizes errors in the device and moving speed output from the sound source position/moving speed calculating unit. A Kalman filter section is provided for outputting the signal.

〔Example〕

The invention will now be described in detail with reference to Figure Uii.

FIG. 1 is an output diagram of one embodiment of the present invention. The definition of '# and ψi shown in FIG. Sonobuoy position measurement unit 4 for measuring the positions of passive sonobuoys 1 to 3. A frequency analysis section 51 performs frequency analysis of the underwater sounds supplied from the bass pumps 1 to 3. A sound identification section 6 identifies the characteristic sound frequency of the target sound source from the frequency analysis results of the frequency analysis section 5. ．． A sound source position where the position and moving speed of the mesono gui are calculated based on the position information of the passive sonogui 1 to 3 by the nonpui position measurement unit 4 and the drag displacement amount of the frequency specified by the target sound identification unit 6.・The passive sonograph is equipped with a Kalman filter section 8 that temporally tracks the sound source position and moving speed outputted from the S work rate calculation section 7 and the sound source position/moving speed calculation section 7 and minimizes the error. All except 1 to 3 are carried on the receiving aircraft.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

The underwater sound captured by the three non-directional bass sonophones 1 to 3 is sent to the aircraft-mounted frequency analyzer 5 using different radio waves such as VHF radio waves.

The sonobuoy position measurement unit can easily know the position of each passive sonobuoy, which is the source of one radio wave, by receiving the non-1flA radio waves sent out by the passive sonobuoys 1 to 3 using a directional antenna.

Three passive sonoguidles 1 supplied to the frequency analysis section 5
The signals from 3 to 3 are converted from time domain to frequency domain data using Fourier transform etc. in a 3 channel frequency analysis circuit corresponding to each passive sonograph.
supplied to

Based on the analysis results of the three channels provided by the target sound identification unit 6f'i and the frequency analysis unit 5, the frequency of the sound emitted by the target i is determined for each of the three sonobuoys, one for each sonobuoy identified. , the frequencies of the three received sounds are supplied to the sound position/moving speed calculating section 7. These frequencies are
In response to the Dotsupura displacement corresponding to the relative speed of the target and the passive sonobuoy, the Dotsupura frequency differs for each sonobuoy.

The sound source position/moving speed calculation unit 7 calculates the target position, moving speed, and moving direction as follows using the drag displacement frequency that differs for each passive sonoguid. It is an explanatory view showing contents of sound source position, moving speed, and direction determination in the example of a figure.

Passive Sonogui 1, 2, and 3 are each 0. A.

Assume that at position B), the position dX of the target sound source is at a distance r in the direction β from the position ltO of the passive sonograph, and the target sound source is moving in the direction α at a speed υ.

γ1. Let βl+'ri+β2 be known and the Doppler-displaced frequencies observed by each passive sonoguid 1, 2.3 are fo and fx-f2, respectively.

The Doppler effect when the sound source moves is given by the following equation (1).

C fn=fs...
・・・・・・・・・(1) C+υn In equation (1), f= is the frequency of the 9-sound sound source X, and C is the speed of sound, υn
is the relative velocity between the target sound source and the observed sonobuoy, and 7'n is the observed frequency.0 When the fl1 formula is transformed, six formulas are obtained that yield the following formula (2).

f6acos(β-α)・Gei-11)+ft C08
(tt-α)・ge. −fz )+f2cos(θ2−α
)・(jt fo)−0・・・・・・・・・・・・(
6) Expression (6) will be written as Ft-・(α ri β θ x 5 θ 2) 20 Next, let's consider the relationship between the number of observations, unknowns, and the number of formula 4. First, at time to, the relative speed TJn of the target sound source and the observed sonobuoy can be expressed using the relative position of the sonobuoy and the target sound source, υ, α, and according to equation (2), for each sonobuoy, next(
Three equations 3) to (5) are derived.

If Δ is 1 at later time tl, [3), 14), and fs and υ are eliminated from equation [5], the following (6) is obtained. However, during the short time Δ, the target is considered to be moving straight at a constant speed.

By the way, if the number of observations is k, the number of equations is 5-2), α, β, θ8. θ3. γ, βl#θl/.

The number of unknowns such as θ2' and γ' is 4 + 1.0 The solution is found when the number of equations ≧ unknowns, so 4 + 1 ≦ 5 -
2 ≧ 3, and if you perform at least 3 observations, you will reach the target position.

Movement speed and direction can be determined.

By the way, in the above picture ill, generally the sonogui position 1
Since there is a measurement error in the first observation of the frequency, calculations of the target position, etc., include errors.

The Kalman filter section 8ri minimizes the error between the target position and movement speed sent from the sound source position/movement speed calculation section at time and time by the method described below.If the output of the sound source position/movement speed calculation section is Yt, , the estimated value &1/1 at time t is given by the following equation: O X coordinate of position, y coordinate, velocity component of target in X direction.

(This is a matrix whose elements are velocity components in the y direction), and specifically, it is expressed as follows.

Octopus, ■ is an identity matrix with 4 rows and 4 columns, and F is a matrix with 4 rows and 4 columns, which is expressed by the following equation.

O has the effect of realizing an inexpensive target position detection device that can accurately detect the position and movement direction of

[Brief explanation of the drawing]

is a matrix called the Kalman gain that can be easily obtained by subtracting the equation generally called the Riccati equation, and in the case of this system, it is a matrix of 4 rows and 4 columns. This Kalman gain is determined by considering the magnitude of system noise and bayonet noise. By performing such filtering, errors included in the output of the sound source position/moving speed section can be minimized. [Effects of the Invention] As explained above, according to the present invention, the door 1 of the sound emitted by the target observed with the three omnidirectional passive nozzles is
M by looking at two frequency changes and using a Kalman filter
This is an explanatory diagram showing the contents of target determination using only three non-directional bass sonobuoys by applying the A difference minimization process.・
Nobuoy position measurement section, 5... Frequency analysis section, 6
...Target sound identification section, 7...Sound source position.
Movement speed calculation section, 8...Kalman filter section. Agent Patent Attorney Shinkyo Uchihara 1st time 2nd time

Claims (1)

[Claims] Three omnidirectional passive sonobuoys deployed in the operational area, a sonobuoy position measurement unit that measures the positions of the three passive sonobuoys, and a frequency analyzer that analyzes the frequency of underwater sound signals sent from the passive sonobuoys. a target sound identification unit that identifies a characteristic sound frequency of the target sound source from the analysis result of the frequency analysis unit; and a sound source based on the frequency of the target sound that is Doppler displaced from the position information of the passive sonobuoy. A sound source position/moving speed calculating section that calculates the position and moving speed of the sound source, and a Kalman filter section that minimizes errors in the position and moving speed output from the sound source position/moving speed calculating section. target position detection device.