Based on time and space phase compensation algorithm for GM-APD photonic coherent lidar detection

Abstract

When detecting rough surface targets with a photon coherent lidar system, the wavelength of light is significantly smaller than the height of the surface roughness. This discrepancy induces decoherence effects, which degrade heterodyne efficiency and reduce the signal-to-noise ratio (SNR). To mitigate these challenges, we propose a time and spatial phase compensation signal processing algorithm. In this method, the spatial phase compensation algorithm is first applied to address the issue of phase inconsistency in the array detector signals. Subsequently, to handle the phase mismatch across multiple frames of the GM-APD signals, a time-phase compensation algorithm is employed to align the phases of the multi-frame signals. Finally, the signals are accumulated in the time domain across multiple frames to obtain the final processed signal. A spatial photon coherent lidar system was established to detect four different targets. The application of this algorithm results in a significant improvement in the SNR, with the maximum increase reaching approximately 14.43 dB and the minimum increase at around 8.45 dB. This research lays a solid foundation for the detection of non-cooperative targets in field conditions using photon-coherent lidar systems.