Precise Positioning and Attitude Determination of Small Satellites Using a Software-defined Radio

Current GPS technologies for satellite navigation are relatively costly, heavy, and utilize a high amount of power. This makes such systems difficult for small satellites to support. In this paper, we describe a lowcost, low-weight, low-power GPS navigation system to support smaller satellites. A key component of our solution involves our patented TIDGET-based receiver design, which takes a brief snapshot of GPS data and powers off until the next position fix is desired. The processing of the TIDGET snapshot data is implemented in a software defined radio (SDR) using a GPS software application. This approach shares the resources available within a spacecraft’s SDR to support both communication and navigation functions reducing the size, weight and cost of the hardware on a micro/nanosatellite. An important aspect of the TIDGET is its modular design, which allows multiple TIDGETs to be placed on the satellite shell for full GPS visibility and robustness to satellite spin.