Indian Regional Navigation Satellite System (IRNSS)

Satellite-based Navigation System has emerged as a forerunner in providing the positioning, navigation and timing (PNT) services to the users across the world. India has entered into the arena of satellite navigation with its two major projects viz. GAGAN (GPS Aided Geo Augmented Navigation), & IRNSS (Indian Regional Navigation Satellite System). GAGAN is a space-based augmentation for GPS developed jointly by ISRO and Airports Authority of India (AAI) to meet the stringent Civil Aviation Requirements. IRNSS is ISRO's initiative in developing India's indigenous regional navigation system providing PNT services to users in the Indian region.

IRNSS - Indian Regional Navigation Satellite System

Indian Regional Navigation Satellite System (IRNSS) project envisages establishment of a regional navigational satellite system using a combination of GEO and GSO spacecrafts and state-of-the-art ground systems. The IRNSS System provides navigation solution all time with position accuracy better than 20m during all weather conditions, anywhere within India and a region extending about 1500 km around India. IRNSS provides Standard Positioning Service (SPS) and Restricted Service (RS) to the users on dual frequencies in L5 and S band.

IRNSS is an independent regional navigation satellite system being developed by India. It is designed to provide accurate position information service to users in India as well as the region extending up to 1500 km from its boundary, which is its primary service area. IRNSS will provide two types of services, namely, Standard Positioning Service (SPS) and Restricted Service (RS) and is expected to provide a position accuracy of better than 20 m in the primary service area.

IRNSS-1A is the first satellite in the Indian Regional Navigation Satellite System (IRNSS). PSLV-C22 launched IRNSS-1A on July 01, 2013 It is one of the seven satellites constituting the IRNSS space segment. IRNSS-1A carries two types of payloads navigation payload and ranging payload. The navigation payload of IRNSS-1A will transmit navigation service signals to the users. This payload will be operating in L5 band (1176.45 MHz) and S band (2492.028 MHz). A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1A consists of a C-band transponder which facilitates accurate determination of the range of the satellite. IRNSS-1A also carries Corner Cube Retro Reflectors for laser ranging.

Applications of IRNSS

• 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 travelers
• Visual and voice navigation for drivers

India launched satellite IRNSS-1D atop a Polar Satellite Launch Vehicle from the Satish Dhawan Space Centre at Sriharikota, about 90 km from Chennai on 28 March 2015. IRNSS-1D, which joined India’s three other satellites already in orbit, was the fourth in the planned seven of the Indian Regional Navigation Satellite System (IRNSS) constellation. The first three satellites in the IRNSS series were launched from Sriharikota in July 2013, April and October 2014 respectively. The IRNSS series was designed to provide the country's own navigation system together with the US-designed GPS.

GAGAN - GPS Aided GEO Augumented Navigation

GPS Aided GEO Augmented Navigation (GAGAN) is a step by the Indian Government towards initial Satellite-based Navigation Services in India. It is a system to improve the accuracy of a global navigation satellite system (GNSS) receiver by providing reference signals. The Airports Authority of India (AAI) and Indian Space Research Organization (ISRO) have collaborated to develop the GPS Aided Geo Augmented Navigation (GAGAN) as a regional Satellite Based Augmentation System (SBAS). The GAGAN's goal is to provide a navigation system to assist aircraft in accurate landing over the Indian airspace and in the adjoining area and applicable to safety-to-life civil operations. GAGAN is inter-operable with other international SBAS systems.

GAGAN Payload is now operational. The satellites GSAT-8 and GSAT-10 satellites have the GAGAN payloads. The third payload of the system was launched with GSAT-15 satellite which is scheduled for launch in late of 2015. The total approximate cost of the project is Rs 7.74 billion ($117 million) and is being created in three phases since 2008.

GAGAN is the first Satellite-Based Augmentation System in the world which has been certified for approach with vertical guidance operating in the equatorial ionospheric region. GAGAN covers the area from Africa to Australia and has expansion capability for seamless navigation services across the region. GAGAN provides accuracy, availability, and integrity essential for each phase of flight, en route the approach for airports within the GAGAN service volume. This makes airline operations more efficient and effective, increase air safety, and fuel efficiency. Further, with vertical guidance at runways, a significant cost will be saved due to withdrawal of ground aids and reduced workload of airline crew and traffic controllers.

One essential component of the GAGAN project is the study of the ionospheric behaviour over the Indian region. GAGAN ionospheric algorithm was developed by ISRO. This makes India the third country in the world which has such precision approach capabilities. GAGAN has been developed for aviation but it will provide benefits to other sectors as well like transportation, railways, surveying, maritime, highways, telecom industry, and security agencies.