Modeling of laser optical detection system for detecting target’s sensitivity and analysis of the impact of optical heterodyne detection performance

Abstract

Aiming at the problem of random interference existing in traditional laser detection target signal, in this paper, we introduce the mechanism of optical heterodyne imaging, study the active laser photoelectric detection system. From the angle of environmental illumination and target reflected laser illumination, we establish the model of the detection system’s sensitivity. According to the parameters of laser photoelectric detection system, we analyze the design method of optical heterodyne imaging detection system. Combining with characteristic parameters such as transmitting laser power, background illumination, target characteristic and local oscillator light source power, we deduce the output current signal function of photoelectric detection receiver, and give the signal to noise ratio (SNR) model of detection system. Through calculation and experimental analysis, in the active laser detection system, with the increase of the difference between the target reflected laser illumination and the background environment illumination, the SNR and the sensitivity of the system are improved. The SNR of the system is obviously changed by changing the power of local oscillator source. The experimental results are in good agreement with the calculated results.