Indian GPS Overlay System Wins Provisional Certification

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India’s GAGAN ground- and space-based GPS augmentation system has won provisional approval from the country’s civil aviation authorities to provide mid-route aircraft navigation services, the Indian Space Research Organisation (ISRO) announced Jan. 3.

Developed by ISRO and the Airports Authority of India at a cost of 7.74 billion rupees ($126 million), the GPS Aided Geo Augmented Navigation, or GAGAN, system uses a network of eight ground stations to enhance the accuracy and monitor the integrity of signals from the U.S. GPS satellite navigation constellation. The corrected signals are then sent up to a pair of geostationary-orbiting satellites, which relay the data directly to aircraft cockpits.

ISRO’s provisional Required Navigation Performance 0.1 certification will enable aircraft equipped with GAGAN receiver equipment to use the service “for en-route navigation and non-precision approaches without vertical guidance over Indian air space,” ISRO said in a statement. 

The GAGAN system “is poised to achieve the next level (APV1/1.5) of certification in the near future to offer precision approach services over the Indian land mass,” ISRO said.

Currently the GAGAN signal is being broadcast via two geostationary ISRO satellites: GSat-8, launched by a European Ariane 5 rocket in May 2011, and GSat-10, launched aboard an Ariane 5 in September 2012. Together these satellites cover the “whole Indian Flight Information Region and beyond,” ISRO said. 

An on-orbit spare GAGAN transponder will be included on ISRO’s GSat-15 communications satellite, whose launch date has not been announced. The first GAGAN payload was included aboard the GSat-4 satellite, which was lost in an Indian rocket failure in April 2010.

According to ISRO officials, GAGAN is interoperable with similar GPS augmentation systems operated by the United States, Europe and Japan.