I. Introduction
In recent years, for the detection of non-cooperative target remote weak photon echo, as well as to achieve the target distance and speed synchronous detection, the photon counting technology and heterodyne detection technology combined photon pulses heterodyne detection system has been studied. At present researches on the photon pulse heterodyne detection technology is in rapid development period, the theoretical modeling and experimental research is still not complete on the performance of system detection, so far, only a small amount of literature on the ranging precision of direct detection of pulsed laser radar, the study on the photon pulse heterodyne detection system ranging accuracy had not yet been reported in the literature.