Antenna efficiency and aperture optimization analysis of spaceborne coherent wind lidar

Abstract

In this paper, the effects of turbulence intensity and transmit-receive matching angle residuals on detection performance of spaceborne coherent wind lidar were studied and analyzed. The antenna efficiency equation was derived and simulated in the target plane by Monte Carlo and Backpropagated local oscillator (BPLO) methods. Normalized CNR was defined as a measure. The antenna aperture corresponding to the maximum normalized CNR was considered optimal. We simulated the optimal aperture with different mismatch angles of 0 µrad, 2 µrad, 4 µrad, and 6 µrad under weak, intermediate, and strong turbulence intensities respectively. From the simulation results, it is concluded that:as the turbulence intensity and angular residual increase, the coherence length and the optimal antenna aperture decreases. Besides, under strong turbulence, the effect of mismatch angle on the normalized CNR is weakened and the appropriate range of antenna aperture is narrow. The optimal antenna aperture is about 400 mm under the condition of weak or intermediate turbulence.