Satellite Navigation service is an emerging satellite-based system with commercial and strategic applications. ISRO is committed to provide the satellite-based Navigation services to meet the emerging demands of the Civil Aviation requirements and to meet the user requirements of the positioning, navigation and timing based on the independent satellite navigation system. To meet the Civil Aviation requirements, ISRO is working jointly with Airport Authority of India (AAI) in establishing the GPS Aided Geo Augmented Navigation (GAGAN) system. To meet the user requirements of the positioning, navigation and timing services based on the indigenous system, ISRO is establishing a regional satellite navigation system called Indian Regional Navigation Satellite System (IRNSS).
GPS Aided Geo Augmented Navigation (GAGAN)
GAGAN Stability tests were successfully completed in June 2013. The overall performance of the systems was reviewed by the review committee. As part of certification activity, DGCA personnel visited GAGAN complex, Kundalahalli in Bengaluru and carried out final inspection activities on Indian Land Uplink Station (INLUS), Indian Master Control Centre (INMCC), Indian Reference Earth Station (INRES) and other facilities.
The implementation of GAGAN has numerous benefits to the aviation sector in terms of fuel saving, saving in equipment cost, flight safety, increased air space capacity, efficiency, enhancement of reliability, reduction in work load for operators, coverage of oceanic area for air traffic control, high position accuracy, etc. The quantum of benefits in the aviation sector would depend on the level of utilisation of such benefits.
Some of the benefits GAGAN is expected to bring for Civil Aviation sector are:
- Safety benefits – Vertical guidance improves safety, especially in adverse weather conditions
- Reduction of circling approaches
- Environmental benefits–Approach with Vertical Guidance procedures will help facilitate better energy and descent profile management during the final approach
- Global seamless navigation for all phases of flight including arrival, departure, oceanic and en route
- Allow direct routings, multiple approaches resulting in considerable fuel savings to airlines and provide for capacity enhancement of airports and airspace
In addition to aviation sector, GAGAN is expected to bring benefits to other sectors like:
- Navigation and Safety Enhancement in Railways, Roadways, Ships, Spacecraft
- Geographic Data Collection
- Scientific Research for Atmospheric Studies
- Natural Resource and Land Management
- Location based services, Mobile, Tourism, etc
Indian Regional Navigation Satellite System (IRNSS)
IRNSS will provide two types of services, namely, Standard Positioning Service (SPS) which is provided to all the users and Restricted Service (RS), which is an encrypted service provided only to the authorised users. The IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area.
Space Segment consists of seven satellites, three satellites in GEO stationary orbit (GEO) and four satellites in Geo Synchronous Orbit (GSO) orbit with inclination of 29° to the equatorial plane. All the satellites will be visible at all times in the Indian region. The first satellite is scheduled to be launched in 2013 and the total seven satellite constellation is scheduled to be in place by 2016. Ground Segment is responsible for the maintenance and operation of the IRNSS constellation. It provides the monitoring of the constellation status, computation of the orbital and clock parameters and navigation data uploading. The Ground segment comprises of TTC & Uplinking Stations, Spacecraft Control Centre, IRNSS Timing Centre, CDMA Ranging Stations, Navigation Control Centre and Data Communication Links. Space segment is compatible with single frequency receiver for Standard Positioning Service (SPS), dual frequency receiver for both SPS & RS service and a multi-mode receiver compatible with other GNSS providers.
Some applications of IRNSS are:
- Terrestrial, Aerial and Marine Navigation
- Disaster Management
- Vehicle tracking and fleet management
- Integration with mobile phones
- Precise Timing
- Mapping and Geodetic data capture
- Terrestrial navigation aid for hikers and travellers
- Visual and voice navigation for drivers