RU2042153C1 - Device for determination of distance to bottom - Google Patents

Abstract

FIELD: hydroacoustics. SUBSTANCE: enhanced accuracy of measurement is achieved through more accurate measurement of time of travel of radiated signal to ground and backward which is determined in this case by maximum coefficient of cross-correlation of squares of envelopes of received echo signal and radiated signal. Device is provided with harmonic signal oscillator 1 connected with radiator, receiver 3 connected with amplifier 4 through detector 5 and correlator; device is additionally provided with two computer units 6 and 9 for calculating the envelope square. Input of harmonic signal envelope square computer 9 is connected with output of harmonic signal oscillator 1 and its output is connected with first input of correlator 7. Harmonic signal envelope square computer 6 is connected between detector 5 and second input of correlator 7. EFFECT: enhanced accuracy of measurement. 1 dwg

Description

 The invention relates to sonar and can be used to determine the distance to the bottom.

 A device for the correlation determination (measurement) of depth under the keel of the vessel is known. Its disadvantage is the limitation of the measured distance by the value of the correlation interval of the signal.

 The closest technical solution is a device for determining the distance to the bottom (echo sounder), containing a harmonic signal generator connected simultaneously with the emitter and the first input of the correlator, containing a receiver connected through a series-connected amplifier and detector with the second input of the correlator, the output of the latter is connected to the indicator.

 The disadvantage of the echo sounder is the complexity and lack of accuracy in determining the correlation time delay corresponding to the maximum of the mutual correlation coefficient of the received and emitted signals. This is explained by the weakly expressed maximum of the cross-correlation function (VKF), which limits the accuracy of determining the distance, the stability of the work, and the range of measured distances to the bottom.

 The aim of the invention is to increase accuracy.

This is achieved by the fact that in the device for determining the distance to the bottom two identical blocks for calculating the square of the envelope are introduced, included at the corresponding inputs of the correlator. In this case, the correlator calculates the correlation time delay from the maximum cross-correlation coefficient of the squares of the envelopes of the received echo signal (reflected) from the bottom and the emitted signal. This made it possible to increase the sharpness of the maximum of the mutual correlation of the squares of the envelopes in comparison with the VKF and thereby increase the accuracy of determining the correlation time delay corresponding to this maximum. Such an increase in accuracy is achieved due to the quadratic formula of the VKF, usually described by a power factor, so for the VKF of the form
ρ _xy (τ) = e ^{-b (τ)} cos2πf _o τ, where f _{o is the} frequency of the emitted harmonic signal;
b coefficient taking into account the features of the bottom, a relatively steepness increase of 2˙e ^{-b (τ)} times is obtained, which in the vicinity of the maximum will ensure a gain of exactly 2 times.

 In FIG. 1 shows the proposed device.

 A device for determining the distance to the bottom, comprising a harmonic signal generator 1 connected to an emitter 2, and a receiver 3 connected through an amplifier 4 to a detector 5, as well as a correlator 7, the output of which is connected to an indicator 8. In addition, the output of a harmonic signal generator 1 is connected not only with the emitter 2, but also through the additionally included second block 9 for computing the envelope square with the first input of the correlator 7, and the second input of the correlator 7 is connected through the additionally included first block 6 for computing the envelope with detector output 5.

 The device operates as follows.

The electric signal from the harmonic signal generator 1 is transmitted to the emitter 2, where it is converted into an acoustic signal, which is emitted vertically downward and reflected from the bottom. The reflected signal (echo signal) is received by the receiver 3, converted into electrical signal, amplified by block 4, detected by block 5, and fed to the first envelope square calculation block 6, the output of which is connected to the second input of the correlator 7, the first input of which is the square of the envelope from the output the second block 9 calculates the square of the envelope of the signal from the generator 1 of the harmonic signal. The correlation device 7, using the adjustable delay of the squared envelope of the signal from the harmonic signal generator, searches for the maximum VKF of the squared envelopes of the echo signal and the signal of the harmonic signal generator 1. The maximum occurs when the introduced adjustable delay equals the transport delay (echo). The distance to the bottom is calculated in indicator 8 according to the formula
H C τ / 2, where C is the speed of sound in the medium;
τ delay of the echo signal.

 This device provides for the inclusion of two identical blocks 6 and 9 and new connections.

Claims (1)

 DEVICE FOR DETERMINING DISTANCE TO THE BOTTOM, comprising a harmonic signal generator connected to an emitter, a receiver connected through an amplifier to a detector, and a correlator, the output of which is connected to an indicator, characterized in that the output of the harmonic signal generator is also connected through an additionally included second unit calculating the envelope squared to the first input of the correlator, the second input of which is connected through an additionally included first envelope squared calculator to the amplifier output.