A Case Study of an Hybrid RF and Optical Inter-Satellite Link Terminal to Enhance Optical Pointing

The attitude determination and control system of a satellite plays a crucial role, especially in optical communication systems due to the narrow field-of-view of the laser. In the last years, the space ecosystem has shown a large interest in optical technology due to its high speed, reduced size, weight, and power, and reliable communications link. However, its narrow field-of-view puts some challenges in terms of connectivity. For this reason, an optical terminal requires a pointing, acquisition, and tracking system to establish the link. This work proposes the use of a dual-plane communications system in which optics and low throughput radiofrequency technologies are combined in a single module. This hybrid system leverages on the quasi-omnidirectional ability of the radiofrequency antennas to enhance the optical pointing system. The improvement is evaluated by means of a simulator that includes the dynamic pointing between two spacecraft. Results demonstrate that the designed hybrid system can heavily reduce the pointing error.