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TRM (time reversal mirror) technology based underwater positioning method

A time-reversal mirror and underwater positioning technology, which is applied to measuring devices, instruments, radio wave measurement systems, etc., can solve problems such as increased computational complexity, difficulty in equalizer design and adjustment, and long-term span, and achieve engineering realization Easy, counteract multi-channel effects, simple algorithm effect

Inactive Publication Date: 2013-02-27
HARBIN ENG UNIV
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AI Technical Summary

Problems solved by technology

Frequency domain equalization must predict or measure the newly arrived frequency characteristics, which brings difficulties to the design and adjustment of the equalizer
Time-domain equalization requires a longer time span for the delay line of the equalizer, which increases the complexity of the calculation.

Method used

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  • TRM (time reversal mirror) technology based underwater positioning method
  • TRM (time reversal mirror) technology based underwater positioning method
  • TRM (time reversal mirror) technology based underwater positioning method

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Embodiment Construction

[0019] The present invention is described in more detail below in conjunction with accompanying drawing example:

[0020] to combine Figure 1~3 , the present invention is described in more detail:

[0021] The short baseline positioning system works in the response mode. Each transducer in the short baseline array is fixed in the water with flexible installation, and the position coordinates of each short baseline array element based on the ship coordinate system are obtained after calibration. The short baseline positioning process is to use the transmitter in the array to send an inquiry signal to the underwater transponder, and the transponder will send a response signal after receiving the interrogation signal. Calculate the time delay of the short baseline four-way array element receiving the response signal relative to the transmitting signal to obtain the distance between the two, and finally use the distance intersection solution to calculate the coordinate position ...

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Abstract

The invention aims to provide a TRM (time reversal mirror) technology based underwater positioning method, which mainly comprises the following steps: determining the coordinate position of each array element of a short baseline relative to a geodetic coordinate system, emitting a broadband linear FM (frequency modulation) interrogating signal to the position of an underwater transponder, and determining a signal emission time; receiving the broadband linear FM (frequency modulation) interrogating signal s (t) by the underwater transponder, and estimating a multi-path spread delay length t byusing the s (t); selecting a time window according to the t, and carrying out time reversal processing on the received signals within the range of the time window; carrying out relative real-time detection on the signal (subjected to time reversal) received by an overwater short baseline processor through sliding, and according to the obtained detection result, judging whether a correlation peak is over a preset threshold scope, if so, judging that an answer signal is arrived, and at this moment, determining a signal receiving moment; and calculating the delay inequality of four circuits of signals of a short baseline array so as to obtain a distance, then obtaining a target position through converged calculation. By using the method provided by the invention, the high precision and low noise requirements of a system can be satisfied, and the multi-path influence of an underwater channel cam be offset effectively.

Description

technical field [0001] The invention relates to an underwater positioning method. Background technique [0002] Due to the great attenuation of electromagnetic waves propagating in highly conductive seawater media, radio navigation equipment is limited. In contrast, acoustic signals propagate in sea water with little attenuation and can travel over long distances. As the transmission medium of underwater acoustic signals, the ocean acoustic channel can be regarded as a slowly time-varying coherent multi-channel channel. In the field of underwater acoustic positioning, multi-channel expansion will seriously increase the error probability of underwater acoustic receiver detection signals, thereby affecting the accuracy of positioning accuracy. Therefore, taking effective measures to resist multi-channel has become a key issue in underwater acoustic signal processing, and it is also one of the difficulties in the realization of underwater positioning systems. [0003] Anti-m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S1/80
Inventor 乔钢李壮何超孙宗鑫马雪飞周峰
Owner HARBIN ENG UNIV
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