A Collective Detection Based GPS Receiver for Small Satellites

To solve the problem of autonomous navigation on small satellite platforms less than 20 kg, we propose to develop an onboard orbit determination receiver for small LEO satellites which lack stable Attitude Determination and Control System (ADCS), continuous GPS coverage, or ground tracking. The system is a refinement of existing spaceborne receiver technology built around a new, innovative collective detection and direct positioning algorithm developed by Dr. Penny Axelrad, a reduced set of GPS hardware, and a compact orbit propagator. The small satellite collective orbit determination receiver (SCOR) brings together efficient reference orbit representations, snapshot GPS sampling, collective detection and direct positioning, and modular orbit propagation methods, to produce an effective new approach for onboard support of small satellites. Since the collective detection algorithm does not require continuous GPS tracking to generate navigation solutions, portions of the receiver can be duty cycled to reduce power consumption between measurements. Additionally, this approach allows for satellites without pointing capabilities to obtain sufficient measurements to generate solutions by taking multiple snapshots when the spacecraft attitude is in a favorable orientation with respect to the GPS constellation.