Low Cost, High Precision Navigation and Attitude Determination System for Microsatellites

Microcosm and NAVSYS propose to develop and assess the performance of a precision navigation with integrated attitude determination (PNIAD) system designed specifically for microsatellites (mass < 100kg). Designing hardware for use on microsatellites requires more than simply reducing component size, weight, power, and cost. Satellite attitude properties and motion do not scale linearly with mass. Moments of inertia increase approximately as the fifth power of the radius, and the required control bandwidth decreases as the square of the radius. Thus, small spacecraft will be more agile, but also easier to tumble and will require much faster and more subtle control than traditional large satellites. With these effects in mind, Microcosm and NAVSYS will perform a systems-level design of a PNIAD system. The system will combine GPS receivers, microelectromechanical (MEMS) inertial measurement units (IMUs), and a miniature star tracker under development. Estimated performance for the integrated system will be compared to simulated results. Phase I will establish the design and system requirements for a microsatellite PNIAD system. Phase II will include prototype development and hardware tests. There will also be an option to add an Earth sensor for full redundancy, and an option to integrate Microcosm's software for autonomous orbit control.