A system using LEO telecommunication satellites for rapid acquisition of integer cycle ambiguities

This paper addresses the design of a cm-level carrier-phase navigation system which employs Low Earth Orbit (LEO) satellites for rapid resolution of integer-cycle ambiguities. In the short term, the system aims to combine the Navstar GPS fleet with satellites of the Globalstar Telecommunications constellation. We describe how cm-level carrier-phase positioning can be achieved using signals that were not designed for navigation. Our objective is to perform precision navigation without requiring alteration of the communication payload onboard the satellites. The technique accommodates the beam configuration of the satellite downlink, the bent-pipe architecture of the communication payload, the instabilities of the satellite oscillators and the frequency-dependent phase lags in the user and reference receiver front ends. The object of this paper is to characterize those components of the system necessary to achieve high-integrity high-precision performance objectives