Wednesday 31 July 2013

India’s First Navigation Satellite Launched


ISRO’s Polar Satellite Launch Vehicle, PSLV-C22, successfully launched IRNSS-1A, the first satellite in the Indian Regional Navigation Satellite System (IRNSS), on July 1 from Satish Dhawan Space Centre, Sriharikota. This is the twenty third consecutively successful mission of PSLV. The ‘XL’ configuration of PSLV was used for the mission. Previously, the same configuration of the vehicle was used thrice to launch Chandrayaan-1GSAT-12 and RISAT-1  satellites. After a flight of 20 minutes 17 seconds, the IRNSS-1A Satellite, weighing 1425 kg, was injected to the intended elliptical orbit of 282.46 km X 20,625.37 km.
IRNSS-1A is the first of the seven satellites constituting the space segment of the Indian Regional Navigation Satellite System. IRNSS is an independent regional navigation satellite system designed to provide position information in the Indian region and 1500 km around the Indian mainland. IRNSS would provide two types of services, namely:
  • Standard Positioning Services (SPS) – provided to all users
  • Restricted Services (RS) provided only to authorised users
A number of ground stations responsible for the generation and transmission of navigation parameters, satellite control, satellite ranging and monitoring, etc., have been established in as many as 15 locations across the country.

Payloads

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 travellers
  • Visual and voice navigation for drivers

IRNSS Overview

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. The Extended Service Area lies between primary service area and area enclosed by the rectangle from Latitude 30 deg South to 50 deg North, Longitude 30 deg East to 130 deg east.
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.
IRNSS consists of a space segment and a ground segment. The IRNSS space segment consists of seven satellites, with three satellites in geostationary orbit and four satellites in inclined geosynchronous orbit. IRNSS ground segment is responsible for navigation parameter generation and transmission, satellite control, ranging and integrity monitoring and time keeping.
The entire IRNSS constellation of seven satellites is planned to be completed by 2015-16.
  • ISRO Navigation Centre (INC) at Byalalu, is the nerve centre of the IRNSS Ground Segment. INC primarily generates navigation parameters
  • IRNSS Range and Integrity Monitoring Stations (IRIMS) perform continuous one way ranging of the IRNSS satellites and are also used for integrity determination of the IRNSS constellation
  • IRNSS CDMA Ranging Stations (IRCDR) carry out precise two way ranging of IRNSS satellites
  • IRNSS Network Timing Centre (IRNWT) at Byalalu generates, maintains and distributes IRNSS Network Time
  • Spacecraft Control Facility (SCF) controls the space segment through Telemetry Tracking & Command networks. In addition to the regular TT&C operations, IRSCF also uplinks the navigation parameters generated by the INC

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