Active sonar single-frequency pulse train waveform design and detection algorithm

A waveform design and detection algorithm technology, applied in the re-radiation of sound waves, radio wave measurement systems, measurement devices, etc., can solve the problems of difficult underwater sound detection and complex underwater acoustic environment, and achieve improved detection performance and strong real-time performance. , the effect of resolving the impact

Inactive Publication Date: 2020-01-10
中国船舶重工集团公司七五0试验场
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the underwater acoustic environment is becoming more and more complex, and it cannot be a Gaussian white noise background. The appearance of reverberation makes underwater sound detection difficult. How to effectively suppress reverberation is an urgent problem to be solved for current active sonar

Method used

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  • Active sonar single-frequency pulse train waveform design and detection algorithm
  • Active sonar single-frequency pulse train waveform design and detection algorithm
  • Active sonar single-frequency pulse train waveform design and detection algorithm

Examples

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example 1

[0044] Example 1: If the manual is attached figure 1 As shown, an active sonar single-frequency pulse train waveform design and detection algorithm includes the following steps:

[0045] Step S1: Design single-frequency pulse signal parameters, design single-frequency pulse signal parameters as center frequency 5kHz, sub-pulse effective duration 10ms, duty cycle 0.4, sub-pulse number 4, total duration 100ms, where the parameter spectrum There are 5 comb teeth in the effective bandwidth, and then transmit the signal through the transmitter, and receive the echo data;

[0046] Step S2: Orthogonal demodulation and down-sampling, the transmitted signal and the echo are respectively subjected to quadrature demodulation, and the calculation formula is as follows,

[0047] the s c (t)=exp[2s(t)exp(j2πf d t)] LPF (1)

[0048] r c (t)=exp[2r(t)exp(j2πf d t)] LPF (2)

[0049] Step S3: Set the copy signal, set the scale factor and the number of copies according to the target s...

example 2

[0066] Example 2: If the manual is attached Figure 2-3 As shown, the active sonar single-frequency pulse train waveform design is as follows: single-frequency pulse signal, its calculation formula is as follows,

[0067]

[0068] In shallow sea environment, reverberation is the main interference of active sonar. The anti-reverberation waveform design and the corresponding signal processing algorithm are the basic ways to solve the target detection in the reverberation background. The Q function is used as a tool to analyze the anti-reverberation performance of the signal. The smaller the value of the Q function, the better the anti-reverberation performance. The expression of the Q function is as follows:

[0069]

[0070] The Q function of the short-pulse CW signal is basically consistent in a large speed range, the Q function of the long-pulse CW signal decreases as the speed increases, and the Q function of the single-frequency pulse train signal decreases and then ...

example 3

[0071] Example 3: The single-frequency pulse signal waveform design and detection algorithm verification were completed by means of computer simulation, and the submarine reverberation model was established. During the simulation, it is assumed that the target is located at 1.23s, and the target is in the background of reverberation and noise interference, where the signal-to-mix ratio is 0dB and the noise-to-noise ratio is 0dB. The simulation does 100 experiments, if the target is found at 1.2 / 1.25s, it is considered that the target is detected correctly. Such as Figure 4-9 It is the detection output diagram when the target speed is 0m / s, 1m / s, 2m / s, 3m / s, 4m / s, 5m / s respectively.

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Abstract

The invention discloses an active sonar single-frequency pulse train waveform design and detection algorithm. Firstly, waveform parameters are designed according to detection requirements and hardwareconditions. After the waveform parameters are designed, on one hand, a signal is transmitted by virtue of a transmitter, and received echo data is subjected to quadrature demodulation, downsampling and automatic gain control and then passes a Doppler filter bank; on the other hand, a copy of the signal is set, and the copy of the signal is subjected to the quadrature demodulation and downsamplingand then passes the Doppler filter bank. Finally, two data segments passing the Doppler filter bank are subjected to segmented correlation processing, thus one output is obtained. The method disclosed by the invention is small in calculation amount and strong in real-time performance, a waveform diversity technology is adopted, influence of reverberation on active sonar detection is solved to a certain extent, and the effect of the active sonar detection is improved, thereby having a better engineering application prospect.

Description

technical field [0001] The invention belongs to the field of underwater active sonar detection, in particular to an active sonar single-frequency pulse train waveform design and detection algorithm. Background technique [0002] Existing active sonar usually uses single-frequency signals or frequency-modulated signals for underwater acoustic detection. For the Gaussian white noise background, the matched filter is the optimal detector, as long as the pulse width of the transmitted signal is large enough, the maximum output signal-to-noise ratio can be obtained. However, the underwater acoustic environment is becoming more and more complex, and it cannot be a Gaussian white noise background. The appearance of reverberation makes underwater sound detection difficult. How to effectively suppress reverberation is an urgent problem to be solved for current active sonar. The long single-frequency pulse signal has better anti-reverberation performance for high-speed moving targets...

Claims

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Application Information

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IPC IPC(8): G01S7/527G01S7/539G01S7/537G01S15/88
CPCG01S7/527G01S7/539G01S7/537G01S15/88
Inventor 岳雷
Owner 中国船舶重工集团公司七五0试验场
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