Indian Regional Navigation Satellite System

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Indian Regional Navigation Satellite System ( IRNSS , German: Indian regional satellite navigation system ), also Navigation Indian Constellation ( NAVIC ), is a regional Indian satellite navigation system . In contrast to global systems such as the US GPS and the European Galileo system that is currently being set up , the IRNSS is only designed for use in India. It only covers a 1500 to 2000 km wide belt on the earth's surface.

background

In 2004, the Indian space agency ISRO proposed its own satellite navigation system in order to become more independent from the US GPS system. In September 2005, however, an agreement was signed to participate in the European-led Galileo project. Nevertheless, the Indian government approved the project proposed by ISRO in May 2006 for 14.2 billion Indian rupees (around € 247 million) for the development of an IRNSS consisting of seven satellites and a ground unit. In October 2006 India questioned the cooperation and the offered co-financing of 300 million euros for the Galileo project due to security-related aspects. The possible Chinese access to sensitive Indian data was mentioned in particular. Consideration was also given to using the existing Russian GLONASS system, but this did not seem ideal at the time due to the failed satellites and the resulting poorer coverage.

planning

The satellites, ground stations and receivers for end devices should be produced in India. The system was to be controlled exclusively by India.

Three of the seven satellites were to be placed geostationary , the remaining four in a geosynchronous orbit , but inclined at 29 ° to the equatorial plane . All seven satellites should have a constant line of sight to the ground station in India. The independently developed satellites should have an accuracy of up to 20 meters. The weight of the satellites was planned to be around 1.3 tons each and the energy supply with solar modules with a power output of 1440  watts .

Construction and operation

The first IRNSS-1A satellite was launched on July 1, 2013. With the start of the seventh satellite April 28, 2016 was the completed . With the launch of this satellite, Prime Minister Narendra Modi announced the name NAVIC (Navigation Indian Constellation). The satellite IRNSS-1A, whose rubidium clocks are defective, was then to be replaced by IRNSS-1H, but its launch failed because the payload fairing did not separate from the upper rocket stage. Instead, the defective satellite was replaced in 2018 by the successfully launched IRNSS-1I. In addition, two more identical satellites are available as a reserve.

IRNSS consists of two services: the Special Positioning Service (SPS) and the Precision Service (PS). Both services are broadcast in parallel on the L5 frequency (1.17645 GHz) and in the S band at 2.492028 GHz. The PLC signal is transmitted to a subcarrier of 1.023 MHz by means of binary phase modulation (BPSK), the PS signal for more precise position determination uses the Binary Offset Carrier in the BOC (5.2) configuration. The two different transmission methods are used to support the code division multiplexing method in order to be able to separate the two services broadcast on the same carrier frequency on the receiver side.

Web links

Individual evidence

  1. ↑ KS Jayaraman: India To Develop Regional Navigation System . space.com, May 22, 2006
  2. ↑ europa.eu: GALILEO congregation expands: EU and India sign agreement on September 7, 2005
  3. ↑ Times of India : India puts its money on Galileo October 16, 2006
  4. ↑ Times of India: India may quit EU-led GPS project October 16, 2006
  5. ↑ a b Gunter Krebs: IRNSS 1A, ..., 1K. In: Gunter's Space Page. April 4, 2014, accessed September 10, 2014 .
  6. ^ Indian Space Research Organization: PSLV-C33 Successfully Launches India's Seventh Navigation Satellite IRNSS-1G. April 28, 2016, accessed April 27, 2016 .
  7. ↑ With IRNSS-1G launch, India completes and renames its navigation constellation. In: GPS World. April 29, 2016. Retrieved March 21, 2017 .
  8. ↑ Why navigation satellite IRNSS-1H launch failed: Here is what ISRO chief said. In: The Indian Express. August 31, 2017, accessed October 12, 2017 .
  9. ^ Indian Regional Navigation Satellite System. (PDF; 727 kB) Archived from the original on April 3, 2016 ; Retrieved July 3, 2013 .