Research Of Pulse-Phase Laser Ranging System Key Technologies

Based on the principle of the pulse and the phase laser ranging, this paper puts forward a practical pulse-phase laser ranging system, which has the advantages of long measuring distance, high resolution, strong anti-interference capability, small volume and light weight.The pulse-phase laser ranging system designed by this paper consists of laser transmitting, laser receiving, digital phase measurement and signal processing four parts. The laser transmitting part adopts the design of automatic frequency tracking and direct modulation method, which can launch Semi continuous sinusoidal signal with repetition frequency4MHZ and repetition frequency10KHZ. The laser transmitting part selects the PIN as laser receiving module, completing signal amplification and filter. At the receiving of received signal, the system completes the measurement of phase and flight time.Phase measurement module samples signal4MHZ with high speed A/D chip. The laser transmitting and receiving circuits is simulated and perfected by using the software of ORCAD pspice. Mixing circuit solves the problems of the interference between the high frequency range optical ruler and the low one. The module realizes the rapid and high precision automatic digital phase measurement technology by adopting multi-cycle synchronization phase method. The simulation shows that the signal-to-noise ratio is17.5dB and the phase measurement error is not more than0.0032rad. In actual measurement of the hardware circuit, phase measurement accuracy reaches0.0004rad without adding noise.Finally, analyses of the system error and noise based on the experimental results of laser ranging system and that of simulation are conducted. The ranging accuracy of the whole system was improved, which confirm the feasibility of the pulse-phase laser ranging method. The system completed the measurement of the Phase difference, and the system achieved the design and the simulation of the pulse-phase laser ranging system, and meets the requirements of technical indicators in project issues.