Indian Plan for Satellite-Based Navigation Systems for Civil Aviation

A.K. Sisodia, J.K. Hota, N.J. Vora, A. Siddiqui, H.C. Sanandiya, S.C. Bera

Abstract:	The Indian Space Based Augmentation System (SBAS) known as GAGAN (GPS And GEO Augmented Navigation) system is a Proof of Concept system for introducing satellite-based CNS/ATM services in India. The Indian Space Research Organisation (ISRO) is implementing GAGAN for the Airports Authority of India (AAI). This paper describes the Indian Plan for satellite-based navigation system for civil aviation. The ground segment consists of eight Indian Reference Stations (INRESs), an Indian Master Control Centre (INMCC), an Indian Land Uplink Station (INLUS) and necessary communication links. Grid based Iono-tropo model for low latitude regions will be developed through deployment of a large number of Total Electron Content (TEC) receivers over the Indian sub-continent and analyzing the data collected. An Indian GEO stationary satellite will carry a navigation bent pipe transponder with CxC , CxL1 and CxL5 links. The helical array antennas for L1 & L5 downlinks are powered by 40 Watt RF amplifiers to achieve the required Equivalent Isotropically Radiated Power (EIRP), Preliminary analysis indicates that L1 & L5 downlink EIRPs would be in the vicinity of 33 dBW over the Indian Airspace. This increased EIRP is necessary to incorporate higher baud rates (upto 1 K baud) for L5 downlink and addition of a Q-channel for L1 downlink. Necessary link calculations for the Indian Nav. Payload are presented. Short term clock and carrier coherence is achieved through a highly stable Master oscillator on-board generating all local oscillator frequencies and with closed loop control with the INLUS. The Indian SBAS when operationalised is expected to fill the gap between the European EGNOS and the Japanese MSAS to provide seamless navigation to civilian aircrafts.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	2795 - 2811
Cite this article:	Sisodia, A.K., Hota, J.K., Vora, N.J., Siddiqui, A., Sanandiya, H.C., Bera, S.C., "Indian Plan for Satellite-Based Navigation Systems for Civil Aviation," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 2795-2811.
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