A cross-correlation driven adaptive dual-domain enhancement method for OCMSI measurement

Abstract

Optical carrier microwave scanning interferometry (OCMSI) is a new precision laser ranging method. However, conventional demodulation techniques are incapable of efficiently extracting useful signals from low Signal-to-Noise Ratio (SNR) signals, resulting in serious decrease of ranging accuracy. In this paper, a cyclic inter-correlation method based on combining time and frequency domains is proposed, which aims to facilitate the demodulation of OCMSI distance signals in scenarios characterized by low signal-to-noise ratios, with a concomitant emphasis on both precision and stability. Firstly, the amplitude-frequency spectrum of the interference signal is extracted through a microwave frequency scanning process integrated with synchronous demodulation. Subsequently, the inverse discrete Fourier transform (IDFT) is applied to the interference spectrum to generate the optimal reference signal, after which the mutual correlation function is computed to synthesize the enhanced reference signal. This cross-domain processing strategy effectively isolates and enhances interference signatures for subsequent noise suppression and error compensation. Preliminary simulations offer compelling evidence for the feasibility and efficacy of the proposed methodology. The experimental results show that the ranging accuracy of the algorithm is better than ± 50 μm, and it is improved by 50 % compared with the traditional direct processing method, which proves that the method has good effectiveness and robustness.