Effect of Tracking Errors on Performance of Telescope Arrays Receiver for Deep Space Optical Communication

On Earth, a large aperture telescope is required to achieve the substantial data rates needed for a deep space optical communication link. However, not only are large telescopes very costly but, it is also very difficult to attain near diffraction limited performance with large apertures. An array of relatively smaller sized telescopes combined to form a larger synthesized aperture is a viable and efficient alternative to a large monolithic telescope. However, the performance of telescope arrays needs to be investigated under certain limiting factors such as turbulence, tracking errors etc. In this paper, we analyze the impact of tracking errors on the performance of telescope arrays. A deep space optical communication link between Mars and a telescope array receiver on earth is simulated. A closed loop tracking system is employed at the receiver end to cater for the random tracking errors. Monte Carlo Simulation results show that, under tracking errors the performance of telescope arrays can reach very close to that of a large monolithic telescope with the same total photon collecting area. Hence, telescope arrays are a cost-effective alternative for deep space optical communication.