Real-Time Attitude Determination of a Nanosatellite using GPS Signal-To-Noise Ratio Observations
Abstract
In support of the FASTRAC nanosatellite mission, a COTS, single antenna GPS receiver has been augmented for use in space as a multi-purpose navigation sensor. In addition to providing measurements of position and velocity, the Mitel Orion GPS receiver has been coupled with a three-axis magnetometer to provide robust attitude determination for the FASTRAC nanosatellite pair. An algorithm is presented for attitude determination of small spacecraft using single antenna GPS signal-to-noise ratio observations coupled with a magnetometer. Real-time accuracies of 5-7 degrees RMS are demonstrated in simulation. In addition, a benchmark testing procedure for evaluating the on-orbit performance of the receiver is presented. The procedure is used to characterize the raw measurement accuracy and systematic tracking loop errors for the Orion receiver. An on-orbit demonstration of the integrated sensor is planned for 2006. The integrated device is intended as a low-cost, standard solution for use on small spacecraft. Algorithm and hardware simulation results are provided to show the usefulness, accuracy, and robustness of this approach.
Real-Time Attitude Determination of a Nanosatellite using GPS Signal-To-Noise Ratio Observations
In support of the FASTRAC nanosatellite mission, a COTS, single antenna GPS receiver has been augmented for use in space as a multi-purpose navigation sensor. In addition to providing measurements of position and velocity, the Mitel Orion GPS receiver has been coupled with a three-axis magnetometer to provide robust attitude determination for the FASTRAC nanosatellite pair. An algorithm is presented for attitude determination of small spacecraft using single antenna GPS signal-to-noise ratio observations coupled with a magnetometer. Real-time accuracies of 5-7 degrees RMS are demonstrated in simulation. In addition, a benchmark testing procedure for evaluating the on-orbit performance of the receiver is presented. The procedure is used to characterize the raw measurement accuracy and systematic tracking loop errors for the Orion receiver. An on-orbit demonstration of the integrated sensor is planned for 2006. The integrated device is intended as a low-cost, standard solution for use on small spacecraft. Algorithm and hardware simulation results are provided to show the usefulness, accuracy, and robustness of this approach.
