All-optical focusing coherent laser method and device for symmetric pseudo-random code phase modulation

Abstract

The invention discloses an all-optical focusing coherent laser method and device for symmetric pseudo-random code phase modulation. A laser light source outputs a light beam, and the light beam is divided into a signal light beam and a local oscillation light beam through a polarization-maintaining beam splitter; high-speed electro-optic phase modulation is performed on the signal light beam through the symmetric pseudo-random code, then the signal light beam is sent to a target and an echo light beam of the target is received. Coherent orthogonal reception is performed on the echo light beamand a local oscillation light beam to obtain a coherent receiving signal; a first amplitude type linear array spatial light modulator is used for loading a delay symmetric pseudo-random code in a coherent receiving signal; and meanwhile, the original symmetric pseudo-random code passes through a variable delay circuit to obtain a variable delay symmetric pseudo-random code, all-optical focusing processing is carried out on the variable delay symmetric pseudo-random code and the delay symmetric pseudo-random code, and high-precision distance information of a long-distance target is obtained through the delay amount of a focusing point. The invention can overcome the bottleneck caused by a traditional digital correlation processing mode, has the advantages of high speed and simple structure,can realize high repetition frequency laser radar distance detection, and has the characteristics of miniaturization of the whole system and easiness in operation.

Description

technical field [0001] The invention relates to the technical field of laser radar, in particular to a method and device for phase modulation all-optical focusing coherent laser with symmetric pseudo-random code. Background technique [0002] The use of lidar to measure the target distance in a complex environment, with high real-time performance and measurement accuracy, is an urgent need for autonomous driving environment perception. ability is important. At present, the main principles of laser radar are single pulse time-of-flight method and continuous wave signal frequency modulation technology. The advantages of single-pulse time-of-flight ranging are simple structure and mature technology. The disadvantage is that when working at a long distance, the laser needs to have a very high peak power. In order to ensure the safe operation of the laser, the repetition frequency of the outgoing pulse is low. , so it is difficult to improve the spatial resolution of the measur...

AI Technical Summary

Problems solved by technology

The advantages of single-pulse time-of-flight ranging are simple structure and mature technology. The disadvantage is that when working at a long distance, the laser needs to have a very high peak power. In order to ensure the safe operation of the laser, the repetition frequency of the outgoing pulse is low. , so the spatial resolution of the measurement is difficult to improve

The traditional correlation processing method is all digital, because the distance resolution of the coded waveform is proportional to the modulation rate, that is, the higher the modulation rate, the higher the range resolution, and the higher the modulation rate, the greater the amount of calculation. Therefore, it takes a long time to image the target, and the requirements for the operating environment are also high. Usually, the high-performance Field Programmable Logic Array (FPGA) is the core, and the electronic system is complex and expensive. one of the main bottlenecks

Images