Distributed multi-channel voice coherent laser radar interception method and device

Abstract

The invention discloses a distributed multi-channel voice coherent laser radar interception method and device. A light beam of a laser light source in a radar platform is divided into N output light beams through a 1*N beam splitter, and N is greater than or equal to 2; frequency shift is carried out on each output light beam through a frequency shifter, and the output light beam is divided into alocal oscillation light beam and an emission light beam through a 1*2 beam splitter; the emitted light beams are directionally emitted to a target through beam control to form an array topological structure, the echo light beam of the target is received, N echo light beams and the corresponding local oscillation light beams are subjected to coherent receiving to obtain N signal data, the N signaldata are transmitted to a digital signal processing system, and the data processing system obtains high-definition voice information through demodulation and enhancement of the voice information. Multiple pieces of sound source information can be flexibly obtained through an array topological structure formed by multiple output light beams, and the system has good spatial selectivity, and also has the characteristics of strong anti-noise interference capability, long interception distance, high precision and clear voice.

Description

technical field [0001] The invention relates to the technical field of laser radar, in particular to a method and device for distributed multi-channel voice coherent laser radar interception. Background technique [0002] The laser voice interception radar emits a laser beam to the target and its surroundings, detects the nanoscale weak vibration signal on the surface of the object caused by the sound pressure in real time, and demodulates the signal to obtain the micro-vibration information of the object, so as to realize the long-range The acquisition of passive voice signals at a distance has the advantages of high sensitivity, strong anti-interference, non-contact, long detection distance, security and privacy, etc., and can effectively make up for the shortcomings of traditional electronic interception methods. Intelligence and other fields have important application value. [0003] At present, according to the detection system, laser voice interception radar can be ro...

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Problems solved by technology

Lu Tao et al. (One of the prior technologies, see Lu Tao, Zhang Heyong, Guo Jin, Yan Chunhui, Laser coherent acquisition and enhancement of long-distance speech, Optical Precision Engineering, 2017, Volume 25, Issue 3, 569-575) The all-fiber laser coherent heterodyne vibration measurement system is used, combined with the speech enhancement algorithm based on Wiener filtering to improve the signal-to-noise ratio, but this algorithm needs to first perform noise judgment in the frequency domain and then perform filtering and noise reduction. The effect is very poor in low cases, and it is difficult to apply to real-time high-precision speech acquisition

Rui Li et al. (Second of prior art, see Rui Li, Nicholas Madampoulos, Zhigang Zhu, and Liangping Xie, Performance comparison of an all-fiber-basedlaser Doppler vibrometer for remote acoustical signal detection using short and long coherence length lasers, Applied Optics ,2012,Vol.51,No.21,5011-5018) proposed a method of tunable optical delay line compensation to suppress the noise in the process of heterodyne detection, but this method is not suitable for long-distance detection

Shi-song Wu et al. (the third prior art, see Shi-song Wu, Tao Lv, Xi-yuHan, Chun-hui Yan, He-yong Zhang, Remote audio signals detection using apartial-fiber laser Doppler vibrometer, Applied Acoustics , 2018, 130, 216–221) proposed a free space-fiber hybrid solution to suppress the crosstalk noise introduced by the fiber circulator, but the coupling efficiency of the signal light will decrease, and the system complexity will be increased

[0005] To sum up, although the existing speech enhancement technologies can improve the quality of noisy speech to a certain extent, because these technologies are based on single-channel detection, the noise in the received signal is directly superimposed on the speech signal, so with the environment With the enhancement of noise, its performance will inevitably decline. Especially in a strong noise environment, it is still difficult to achieve good results with the existing voice enhancement technology, resulting in low detection accuracy and poor anti-noise interference ability of the existing voice interception lidar. The voice is not clear, which seriously limits the application prospects

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