Space Applications Algorithms and Initial Simulation Results for the ITT Low-Power Transceiver

Sasha Draganov, Boris Veytsman and Lin Haas

Abstract:	ITT Industries’ Low Power Transceiver (LPT) combines a GPS receiver and a transceiver for space, ground and cross link communications in a single, modular multi- channel unit. This paper describes the LPT’s relative navigation and attitude determination algorithms and initial simulation results. Relative navigation is modeled for the Techsat 21 mission involving three spacecraft, which will fly in close proximity to each other with separations of less than 1 km. Each spacecraft is equipped with an LPT unit. In addition to tracking GPS satellite signals, each LPT also performs two-way communications via cross-links to the other spacecraft. Cross-link range measurements augment those from GPS satellites. Code and phase measurements are differenced for each pair of spacecraft/GPS. Integer ambiguity is estimated by a Bayesian algorithm. Non-redundant measurements from all three pairs of spacecraft are processed via a Kalman filter. The propagation algorithm uses an Earth- centered inertial coordinate system for the relative position and velocity, and takes into account the Earth’s point-mass acceleration and the oblateness term. The absolute position is obtained from the spacecraft’s orbit determination software. In some missions, the LPT will be used to determine the attitude of a spacecraft. An innovative technique is presented for applying corrections to the spacecraft attitude matrix, which ensures that orthonormal/rotational constraints are not violated.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	94 - 102
Cite this article:	Draganov, Sasha, Veytsman, Boris, Haas, Lin, "Space Applications Algorithms and Initial Simulation Results for the ITT Low-Power Transceiver," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 94-102.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In