Health management of laser rangefinder considering maximum continuous working time

High-power lasers have severe thermal effects. The heat buildup during long-term operation will increase the threshold current of the laser and the internal defects, which will seriously affect the lifetime of the device. A temperature sensor is difficult to install on the laser rangefinder due to the small size of the solid-state laser device. Considering this situation, this work analyses the thermal mechanism of the laser rangefinder and proposes a temperature calculation method for the crystal working substance inside the laser rangefinder based on the finite element simulation to obtain the crystal center temperature and thermal model with the working time. Then, the prediction model of the maximum continuous working time of the laser can be obtained. The proposed model can provide an early scientific warning for the remaining continuous working time of the solid-state laser and improve the single-shot utilization of the solid-state laser to a certain extent. A comprehensive health management framework of laser rangefinders including FMEA is also proposed.