AAS 95-334

Designing Clusters of Satellites for Radiolocalisation Purposes

E. Frayssinhes and E. Lansard, ALCATEL ESPACE, TOULOUSE CEDEX, FRANCE

Abstract

High precision localization of beacon positions is achieved by means of an innovative satellite system: a cluster of satellites. Each satellite measures the time-of-arrival of the signal transmitted by the beacon. The derived time-differences-of arrival are processed to estimate the beacon position. This paper investigates the localization accuracy with respect to the cluster geometry. For that purpose, we propose a mathematical formulation relying on a strong analogy with GPS geometrical characterization of navigation performances. This formulation is applied to design the optimal geometry of a cluster made of three LEO satellites, and to assess the impact of its short-term evolution on the localization accuracy. Correlative problems dealing with the relative localization and synchronization of the satellites are also addressed.