GAGAN is an Indian implementation of
Satellite Based Augmentation System (SBAS),
developed jointly by Airports Authority of India (AAI) and Indian Space
Research Organisation (ISRO). It is in final operational phase with all the
required ground and space segments ready. With the availability of GAGAN
signal-in-space (SIS), the improvement in position solution is investigated
using the two collocated dual frequency GPS receivers. One of the receivers was
configured as SBAS
receiver and the other was kept as GPS stand-alone receiver. It is found that accuracy in
significantly in SBAS receiver due
to GAGAN correction. The impact of scintillation on GNSS was also investigated in terms of position
degradation and loss of lock of the satellite signals. The manyfold effects of
scintillation on GPS and SBAS are discussed in detail. The results indicate
~15% reduction in number of measurements due to loss of lock during severe
R. Acharya, M. R. Sivaraman, K. Bandyopadhyay, N. Nagori, S. Sunda and S. Regar, “Ionospheric Studies for the Implementation of GAGAN,” Indian Journal of Radio & Space Physics, Vol. 36, No. 5, 2007, pp. 394-404.
R. J. Kelly and J. M. Davis, “Required Navigation Performance (RNP) for Precision Approach and Landing with GNSS Application,” NAVIGATION: Journal of the Institute of Navigation, Vol. 41, No. 1, 1994, pp. 1-30.
P. V. S. Rama Rao, S. Gopi Krishna, K. Niranjan and D. S. V. V. D. Prasad, “Study of Spatial and Temporal Characteristics of L-Band Scintillations over the Indian Low-Latitude Region and Their Possible Effects on GPS Navigation,” Annales Geophysicae, Vol. 24, 2006, pp. 1567-1580. http://dx.doi.org/10.5194/angeo-24-1567-2006
P. H. Doherty, T. Dehel, J. Klobuchar, S. H. Delay, S. Datta-Barua, E. R. de-Paula and F. S. Rodrigues, “Ionospheric Effects on Low Latitude Space Based Augmentation Systems,” Proceedings of 15th International Technical Meeting (ION GPS), Institution of Navigation, Portland, 2002.
J. Seo, T. Walter and P. Enge, “Availability Impact on GPS Aviation Due to Strong Ionospheric Scintillation,” IEEE Transactions on Aerospace and Electronic Systems, Vol. 47, No. 3, 2011, pp. 1963-1973. http://dx.doi.org/10.1109/TAES.2011.5937276