Control Algorithm of the Hardware Simulator for a Remote Synchronization System for the Japanese Quasi-Zenith Satellite System

Fabrizio Tappero, Ken Nakajima, Toshiaki Iwata, Michito Imae, Yasuhiro Fukuyama, Akira Iwasaki, Ken Hagimoto, Takeshi Ikegami and Hiroshi Murakami

Abstract:	The Japanese quasi-zenith satellite system (QZSS) represents an innovative multi-service satellite system able to provide communication, broadcasting and positioning service improvement for mobile users. The integration of the QZSS with the present GPS and/or the European GALILEO will improve accuracy, availability and capability of the present GPS over a very wide area. Currently, a novel Time Keeping System (TKS) architecture for the QZS is being studied. It consists of a remote synchronization scheme where the satellite-on board time reference is constantly linked to a second, ultra stable, time reference located in the ground station. An up-link/down-link network provides an opportune synchronization/correction signal that keeps the two time references in lock-step. This novel system will need no on board atomic clock. The new TKS concept has been studied through the adoption of a dedicated hardware simulator as well as software simulator tools. The following paper presents the latest hardware/software simulator design changes together with recent architectural improvements. A complete description of the structure of the TKS software simulator his presented. A new adaptive controller for the synchronization of the on board voltage controlled crystal oscillator (VCXO) is also introduced. Considerations of noise modeling are given together with a presentation of some preliminary results of the performance of the VCXO control algorithm.
Published in:	Proceedings of the 2005 National Technical Meeting of The Institute of Navigation January 24 - 26, 2005 The Catamaran Resort Hotel San Diego, CA
Pages:	1001 - 1008
Cite this article:	Tappero, Fabrizio, Nakajima, Ken, Iwata, Toshiaki, Imae, Michito, Fukuyama, Yasuhiro, Iwasaki, Akira, Hagimoto, Ken, Ikegami, Takeshi, Murakami, Hiroshi, "Control Algorithm of the Hardware Simulator for a Remote Synchronization System for the Japanese Quasi-Zenith Satellite System," Proceedings of the 2005 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2005, pp. 1001-1008.
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