Pseudo-random code time delay self-differential interference three-dimensional imaging laser radar method and device

Abstract

The invention discloses a pseudo-random code time delay self-differential interference three-dimensional imaging laser radar method. A differential pseudo-random code sequence is generated after a pseudo-random code generated by a pseudo-random encoder in a radar platform passes through a differential encoder; the differential pseudo-random code sequence performs phase modulation on an output light beam, transmits the output light beam to a target and receives an echo signal from the target; the echo signal is orthogonally received after passing through a non-equal-arm differential interferometer; arc tangent phase solution and high-pass filtering are carried out to obtain phase information, and normalization and binarization are carried out to reconstruct a pseudo-random pulse sequence after target time delay; cross-correlation processing is carried out on the pseudo-random code and the reconstructed pseudo-random pulse sequence after target time delay to obtain distance information of the target; three-dimensional position information is obtained through coordinate system transformation according to angle information; and finally, a three-dimensional point cloud chart is generated. The three-dimensional position information of the target can be accurately obtained. The method has the characteristics of high anti-interference capability, miniaturization of the whole system andeasy operation.

Description

technical field [0001] The present invention relates to the technical field of laser radar, in particular to a method and device for pseudo-random code time-delay self-differential interference three-dimensional imaging laser radar 。 Background technique [0002] Due to the advantages of high directivity, strong anti-interference ability, high measurement accuracy, and high temporal and spatial resolution, lidar technology is widely used in aerospace, national economy, and national defense, such as deep space navigation, satellite-ground synchronous observation, wireless Autonomous rendezvous and docking of manned spacecraft, autonomous safe landing, deep space exploration, vehicle-mounted environment perception, and three-dimensional map construction, etc. The traditional laser radar ranging method often uses the pulsed laser time-of-flight method, that is, to emit pulses with higher peak power, use the time interval of the laser pulse to and fro to obtain distance informa...

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Problems solved by technology

However, if there is a high-speed relative motion between the lidar and the ranging target, a large Doppler frequency shift will be generated. This Doppler frequency shift will lead to the broadening of the correlation peak, causing the deterioration of the correlation performance and affecting the ranging accuracy. Therefore, a certain method must be used to eliminate the Doppler frequency shift of the target during the ranging process to ensure the normal demodulation of the receiver.

In addition, the outdoor atmospheric turbulence will seriously interfere with the pseudo-random code phase modulation ranging, and the system phase noise introduced by the laser line width, laser amplifier and phase modulator will seriously affect the accuracy of the pseudo-random phase ranging

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