The Laser Radar Weak Signal Processing Method Based On Wavelet Transform

Due to its special capabilities, laser radar could complete the tasks which common radar can't achieve. Ladar have been widely used in many different subjects and research fields, such as detection of stealth aircraft, submarine, mine and biochemical weapons. But the detection capability of ladar is limited because of the extremely complex environment for ladar performing. In order to improve detection capability and increase detection range, more effective methods of signal detection and processing have to be found. The noise characteristics of direct detection ladar system are analyzed. The model of ideal transmitted Gaussian pulses and the return waves are created to simulate the transmitted laser and its propagation. In order to process the simulated received signal, we propose a new approach called Wavelet Multi-resolution Threshold and Correlation Denoising, which is more suitable for weak signal processing of ladar system. Some appropriate wavelets methods and the optimal decomposition levels are analyzed, and also the feasibility and validity are evaluated by simulation. For irregular received signals, we add the Automatic Gain Control system (AGC system) for the denosing processing. The restoration of signals and the improvement of SNR is proven to be effective. The methods of this paper could effectively increase the ladar detection capability of weak signals.