Relative state estimation and observability for formation flying satellites in the presence of sensor noise

This paper presents an investigation of the relative state estimation and observability for two formation flying satellites using two different relative navigation sensor sets. The first set consists of a transmitter antenna on one satellite and a single receiver antenna on the other satellite to measure the inter-satellite range using a radiofrequency ranging signal. The second set uses three receiver antennas to measure multiple ranges, effectively providing angular information. In this paper, it is shown for the more complete sensor set that the estimation error in the relative state is a function of the pseudorange error, the inter-satellite distance, and the receiver antenna baselines. By varying these parameters, conditions are found for which the measurements obtained using the first sensor set result in relative state estimation and observability comparable to those obtained with the more complete sensor set. This offers potential reductions in cost and complexity for certain mission scenarios.

► We study the relative state estimation and the observability for two formation flying satellites.
► Two different inter-satellite radiofrequency ranging sensor sets are compared.
► We derive empirical relationships for the accuracy in the estimation for both sensor sets.
► The results suggest that cost and complexity can be reduced for certain mission scenarios.