Parameter Design for Inter-Satellite Laser Link Acquisition Under Weak Light Conditions

For the Taiji program or other LISA-like space-based gravitational wave (GW) detection missions, establishing laser links is a prerequisite for entering the normal science mode. There has been a lack of in-depth research on inter-satellite link acquisition under weak light and low-speed conditions. In this paper, we comprehensively analyze the impact of key parameters, including scan speed, track width, acquisition camera integration time, and jitter, on the acquisition process. By introducing laser spot location error under weak light conditions, we derive an analytical expression for the acquisition failure probability. Focusing on variations in scan speed and track width and carefully selecting the appropriate acquisition camera integration time, we then simulate the actual acquisition process to closely replicate real conditions. Analytical results of the acquisition failure probability align closely with the simulation results. Under the Taiji program’s parameter settings, the scan speed is set to 3.31 μrad/s, the track width to 0.87 μrad, and the integration time to 800ms. These parameters are optimized to minimize the mean acquisition time over multiple scans, resulting in a single link acquisition time of 223.77s. The analytical model can be used for the parameter design of inter-satellite laser link acquisition under weak light conditions.