Improving the range accuracy of Gm-APD photon counting chirped amplitude modulation ladar with minimum variance unbiased estimation method

Due to the limitation of the increase of the sampling frequency and modulation bandwidth resulting from the dead time of the Gm-APD detector of photon counting chirped amplitude modulation ladar and the discrete FFT spectrum of the echo signal, the improvement of range accuracy is hard to achieve. The echo signal was deduced according to the signal processing. The expression of the IF signal was obtained, and the method was processed. Finally, the method was simulated and its result was compared with the simulation result of the center of gravity estimation method. The result that the maximum range error is reduced from 4.3m to 0.4m shows that the IF signal processing method of the minimum variance unbiased estimation improves the range accuracy of photon counting chirped amplitude modulation ladar with Gm-APD as the detector greatly.