RU2525472C1 - Acoustic range-finder - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: acoustic range-finder has higher accuracy of range-finding owing to use of a tuneable frequency generator, maximum signal indicator, a signal trailing edge determining unit, an adjustment code output panel and a subtractor, wherein the output of the tuneable frequency generator is connected to the input of the indicator and the input of an acoustic wideband, low-frequency band receiver, and the input of the generator is connected to the output of said receiver, also connected to the input of the maximum signal indicator and through the signal trailing edge determining unit to the second input of a time mismatch converter, the group of outputs of which is connected to a first group of inputs of the subtractor, having a second group of inputs connected to a group of outputs of the adjustment code output panel and having a group of outputs connected to a group of inputs of the indicator.

EFFECT: high accuracy.

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Description

The invention relates to the field of acoustic technology and can be used in exploration technology in underground and underwater conditions.

Known acoustic device for determining the range described in the book "Acoustics", S. Ya. Vakhitov. Hotline - Telecom, 2009, p. 633. In it, with the help of an acoustic emitter, which can operate in the low-frequency range, the frequency is swayed. Sound waves from the emitter can be reflected from the object and enter the acoustic receiver. During the arrival of the reflected frequency, the emitter frequency will change. The magnitude of this change will characterize the range. However, the accuracy of determining the range is not always sufficient.

Known acoustic device for determining the range described in the aforementioned source on pages 631-632. It can be used acoustic broadband emitter, including low-frequency range, emitting a frequency, for example 15-20 Hz.

Sound waves emitted by the emitter may be reflected from the object. To determine the range, the emitter can emit sound frequency pulses at the moment of arrival at its input, for example, of a signal from a controlled pulse generator. The pulse reflected from the object enters the low-frequency acoustic broadband receiver. The range is determined in the time difference converter by the time interval between the pulse from the generator and the signal from the acoustic receiver and is displayed on the indicator. However, the accuracy of determining the range is not always sufficient. Using the proposed device increases the accuracy of determining the range. This is achieved by introducing a tunable frequency generator, a maximum signal indicator, a trailing edge detection unit, a correction code issuing panel and a subtractor, while the output of the tunable frequency generator is connected to the indicator input and to the input of the low-frequency acoustic broadband receiver, and the generator input is connected to the output of this receiver also connected by the input of the maximum signal indicator and through the block determining the trailing edge of the signal with the second input of the transformer ervala group of outputs of which is connected with the first group of inputs of a subtractor, having a second input group connected to the group output panel issuing correction code and having an output group connected with the group indicator inputs.

In figure 1 and in the text the following notation:

1 - controlled pulse generator

2 - acoustic broadband low-frequency radiator

3 - reflective object

4 - maximum signal indicator

5 - acoustic broadband low-frequency receiver

6 - block determining the trailing edge of the signal

7 - adjustable frequency generator

8 - indicator

9 - time misalignment converter

10-subtractor

11 - panel issuing edit code,

wherein the output of the controlled pulse generator 1 is connected to the first input of the time mismatch transducer 9 and to the input of the acoustic broadband low-frequency emitter 2 having an acoustic output connected to the acoustic input of the reflective object 3, the acoustic output of which is connected to the acoustic input of the acoustic receiver of the low-frequency range 5, having an input connected to the input of the indicator 8 having a group of inputs connected to a group of outputs of a subtractor 10 having a second and ne group of inputs, respectively, connected to the group of outputs of the panel issuing the correction code 11 and to the group of outputs of the transient mismatch transducer 9, having a second input connected via the trailing edge detection unit 6 to the output of the acoustic broadband low-frequency receiver 5, also connected to the input of the maximum indicator signal 4 and having an input connected to the output of the adjustable frequency generator 7, the input of which is connected to the output of the acoustic broadband receiver low frequency range 5.

The operation of the device is as follows.

Sound waves emitted by an acoustic broadband radiator of the low frequency range 2 are reflected from the reflective object 3, which may be, for example, the bottom of a well formed as a result of drilling. Sound signals are emitted when a pulse arrives at the input of the emitter 2 from a controlled pulse generator 1. In this case, a generator operating mode with elongated and shortened pulses is possible. Reflected sound waves enter the acoustic broadband low-frequency receiver 5, where they are converted into electrical signals. Using the adjustable frequency generator 7, the receiver 5 is tuned to the received frequency at which the maximum amplitude is observed on the maximum amplitude indicator 4. This is due to the fact that there is a resonant effect for a certain frequency, depending on the depth of the well, and at the time of maximum amplitude allocation on indicator 4 on indicator 8, the frequency from generator 7 is fixed, which characterizes the depth of the well. Thus, each resonant frequency will correspond to a certain depth, that is, the distance to the bottom of the well. In this mode, the sound pulse can be elongated and equal to the measurement time. The accuracy of determining the depth can be fractions of a meter. If there is drilling equipment inside the well or other interfering reflectors, there may be no resonance. Therefore, shortened emitting pulses are also used, the repetition rate of which depends on the maximum delay time of the reflected signal. However, the duration of the reflected signal can be increased due to the presence of successive reflections inside the well. Therefore, using the time mismatch transducer 9, the depth to the target at the bottom of the well is determined. In this case, the time mismatch between the pulse from the controlled generator 1 and the trailing edge of the signal from the receiver 5 is measured, which through the trailing edge detection unit 6 is supplied to the second input of the converter 9, and the signal from the generator 1 is supplied to the first input. The execution of the trailing edge detection unit is similar to the block secondary processing, where the signal duration can be analyzed and random signals excluded. An example of a specific implementation of the secondary processing unit is presented in the book "Radio Engineering Systems", V.P. Pestryakov et al., 1985, p. 219. The temporary mismatch code from the group of outputs of the converter 9 goes to the first group of inputs of the subtractor 10, and the second group of its inputs receives the correction code from the panel issuing the correction code 11, characterizing the duration of the acoustic shortened pulse emitted by the emitter 2. The difference from the group of outputs of the converter 9 carrying information about the range, enters the indicator 8 for display.

An example of a specific implementation of the transducer 19 is presented in the book "Reference-task book on radiolocation", Vasin VV, Stepanov BM, -M., 1977, p.214, Fig.9.7. The proposed device can be used to determine the depth of the wells. This increases the accuracy of determining the depth of the beds. The device can be used to determine the range, including to the terminal object, as well as elongated, for example, in mines, tunnels and other enclosed spaces, as well as to determine the depth of water bodies and ranges to suddenly appearing obstacles.

Claims (1)

An acoustic ranging device consisting of a controlled pulse generator, an acoustic broadband low-frequency emitter, a reflective object, a time mismatch transducer and an indicator, where the output of a controlled pulse generator is connected to the first input of a temporary mismatch transducer and to the input of a low-frequency acoustic broadband emitter having an acoustic output associated with the acoustic input of a reflective object, acoustics the output of which is connected to the acoustic input of the acoustic receiver of the low-frequency range, having an input connected to the indicator input, characterized in that it includes: a tunable frequency generator, a maximum signal indicator, a signal trailing edge detection unit, a subtractor and a correction code issuing panel, while the output the adjustable frequency generator is connected to the input of the indicator and to the input of the acoustic broadband low-frequency receiver, and the input of the generator is connected to the output of this a nickname, also connected by the input of the maximum signal indicator and through the signal trailing edge determination unit to the second input of the time mismatch converter, the group of outputs of which is connected to the first group of inputs of the subtractor having the second group of inputs connected to the group of outputs of the panel for issuing the correction code and having the group of outputs, connected to a group of indicator inputs.