OD&TS Process Evolution Based on Interoperability Between Different Navigation Satellite Systems

M.D. Laínez, M.M. Romay

Abstract:	The objective of this paper is to investigate the potential improvements that would be obtained in the operation of a GNSS navigation system, if the original constellation was augmented with a regional Low Cost Navigation Satellite System (LCNSS) constellation, based on the use of geosynchronous satellites. The performed analyses are supported by the study of the covariance matrix for the different considered Orbit Determination and Time Synchronization (OD&TS) scenarios. A dedicated tool has been developed for simulating the processing of a batch of input ranging measurements so that a realistic estimation of the accuracy of the OD&TS process involved parameters can be obtained. The considered ranging measurements are both usual pseudo-range and phase measurements obtained from Earth tracking stations, as well as inter-satellite links (ISL). These ISL are also navigation signals based on pseudo-range and phase measurements, but between pairs of satellites, instead of between a satellite and a tracking station. The use of ISL is a key issue in the improvement of the relative tracking geometry. It is thus fundamental for the improvement of the OD&TS processes under investigation, as well as for integrity. In addition, ISL processing between satellites belonging to different constellations may help the interoperability between the different systems, ensuring compatible geodetic and clock references. Improvements are expected to be obtained in one or several of the following aspects, depending on the selected GNSS and LCNSS interoperability scenario: positioning accuracy tracking network optimization integrity interoperability The outcomes of the performed work are expected to be relevant for the evolution of the GNSS systems, and for the evolution of the interoperability concept between them and other navigation systems.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	1504 - 1518
Cite this article:	Laínez, M.D., Romay, M.M., "OD&TS Process Evolution Based on Interoperability Between Different Navigation Satellite Systems," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 1504-1518.
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