Geolocation and Attitude Determination from Laser Communication Systems

To realize the benefits of formation flying multi-spacecraft clusters, four key elements must be present: 1. Broadband inter-spacecraft communications to enable the transport of high resolution sensor data. 2. Precision inter-spacecraft timing synchronization to enable precise multi-sensor sampling throughout the cluster. 3. Precision inter-spacecraft relative range to enable the determination of spacecraft and sensor spacing within the cluster. 4. Precision inter-spacecraft relative position and attitude determination to enable geolocation of cluster craft and sensor planes. An inter-spacecraft laser communications network is the only integrated subsystem that can provide all four of these key elements. The proposed SBIR Phase I effort will leverage several existing SPI programs to extend the resulting models, analyses, and designs beyond the normal scope of a Phase I effort, and--should a follow-on Phase II be awarded--produce fully-functional prototype hardware at a minimum cost. Space Photonics and its subcontractors will develop the analytical models, algorithms, calibration processes, and VHDL code for the inter-spacecraft ranging, timing synchronization and inter-spacecraft position and attitude determination; and will (sub-scale) demonstrate these functions in our gimbal-less, free space optical, lasercom testbed (LaserFire® testbed). However, the algorithms, calibration processes, and VHDL code developed for this SBIR Phase I program can be applied to any gimbaled or gimbal-less lasercom crosslink system. These functions can even be applied to RF crosslink systems (the RF implementation will suffer significant loss of inter-spacecraft position accuracy due to the larger RF beamwidths).