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IRNSSIndian Regional Navigation Satellite

System

SAAD BABAR ABBASIMS-GNSS-02150511011

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CONTENTSBACKGROUND

WHY LAUNCHED?

SATELLITE CONSTELLATION

SATELLITE GENERATIONS

ARCHITECTURE

IRNSS SIGNAL

IRNSS COVERAGE

REFERENCE FRAME

PERFORMANCE (IRNSS vs GPS)

SERVICES

BENEFITS

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BACKGROUND

Approved by Government of India in May 2006

The total cost of the project is expected to be US$209 million

In April 2010, it was reported that India plans to start launching satellites by the end of 2011, at a rate of one satellite after every six months

This would have made the IRNSS functional by 2015, but program was delayed

The IRNSS signal has been released for evaluation in Sep 2014

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Why Launched?

Selective availability of GPS signal made it less effective and reliable

Access to foreign government-controlled global navigation satellite systems (GPS) is not guaranteed in hostile situations

Indian military depending on American GPS during Wars

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SATELLITE CONSTELLATION

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SATELLITE CONSTELLATION

There are 9 satellites in total

3 satellites in GEO stationary orbit

4 satellites in GSO orbit

2 on the ground as stand-by

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SATELLITE GENERATIONS

IRNSS-1A was the first navigational satellite in the Indian Regional Navigation Satellite System series of satellites to be placed in geosynchronous orbit. The satellite was launched on-board PSLV-C22on 1 July 2013 from the Satish Dhawan Space Centre at Sriharikota.

IRNSS-1B is the second out of seven in the Indian Regional Navigation Satellite System. It was very precisely and successfully placed in its orbit through PSLV-C24rocket on 4 April 2014.

IRNSS-1C is the third out of seven in the Indian Regional Navigation Satellite System series of satellites. The satellite was successfully launched using India's PSLV-C26from the Satish Dhawan Space Centre at Sriharikota on 16 October 2014.

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SATELLITE GENERATIONS

IRNSS-1D is the fourth out of seven in the Indian Regional Navigation Satellite System series of satellites system. It was successfully launched using India's PSLV-C27on 28 March 2015.

IRNSS-1E is the fifth out of seven in the Indian Regional Navigation Satellite System series of satellites system. It was successfully launched on January 20, 2016 using India's PSLV-C31

IRNSS-1F will be the sixth and IRNSS-1G will be seventh of the Indian Regional Navigation Satellite System series of satellites. Their launches are planned for March and April 2016

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ARCHITECTURE

The IRNSS architecture mainly consists of:

Space Segment

Ground Segment

User Segment

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ARCHITECTURE

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SPACE SEGMENTBased on various considerations the minimum number of satellites required for IRNSS constellation is worked out to be 7 (3 GEO and 4 GSO).

The 3 GEOs will be located at 32.5º E, 83º E and 131.5º E and the 4 GSOs have their longitude crossings 55º E and 111.75º E (two in each plane).

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GROUND SEGMENT Ground Segment is responsible for the maintenance and operation of the IRNSS constellation. The Ground segment comprises of:

ISRO Navigation Centre

IRNSS Spacecraft Control Facility

IRNSS Range and Integrity Monitoring Stations

IRNSS Network Timing Centre

IRNSS CDMA Ranging Stations

Laser Ranging Stations

Data Communication Network

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USER SEGMENT The User segment mainly consists of:

Single frequency IRNSS receiver capable of receiving SPS signal at L5 or S band

frequency

A dual frequency IRNSS receiver capable of receiving both L5 and S band frequencies.

A receiver compatible to IRNSS and other GNSS signals

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IRNSS SIGNAL PLAN

The first proposal for the Signal and Frequency Plan presented in November 2006 during the First ICG Meeting in Vienna by Indian Space Research Organization (ISRO).

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IRNSS SIGNAL PLAN

Given the similarity with the Galileo signals in terms of services that IRNSS might be providing, the same convention as for Galileo was employed. That is A for the PRS and B and C for the Open Service data and pilot signals respectively

When seen in frequency spectra the overall picture of IRNSS signal would be….

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SPETRA OF SIGNAL IN E-5b BAND

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IRNSS SIGNAL PLANIt is interesting to mention that the Indian Satellite Navigation Programme has been doing much work in the past years on ionospheric and tropospheric modelling in the Region of India what could mean that IRNSS does not plan to use dual frequency at least in the first generation.

Moreover, India also plans to transmit similar signals for the S-band to those we have just described for the L5 band.

The carrier frequency of S-band is at 2491.75 MHz. The modulation schemes and data rates would be the same as for L5 but no final decision on the other parameters has been made yet.

In addition, it seems that India also plans to transmit signals in L1 as announced during the second Meeting of the ICG in India, in 2007.

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FINAL SIGNAL PLAN OF IRNSS

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IRNSS CLOSE UP

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IRNSS COVERAGE 1,500-2,000 km’s around Indian land-mass SAARC countries can use IRNSS navigation system

SAARC members countries included are

India

Afghanistan

Bangladesh

Bhutan

Maldives

Nepal

Pakistan

Sri Lanka

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IRNSS REFERNCE FRAME IRNSS makes use of the International Terrestrial Reference System (ITRS).

The ITRS defines a geocentric system of coordinates using the System International.

An International Terrestrial Reference Frame (ITRF) is a realization of the ITRS. New ITRF solutions are produced every few years, using the latest mathematical and surveying techniques to attempt to realize the ITRS as precisely as possible.

IRNSS Time is the reference time generated by IRNWT (IRNSS network timing).

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IRNSS PERFORMANCECurrent status with 4 satellites of IRNSS, the GDOP (Geometric Dilution of Precision varies from 2m to 9m in a day) which means we are getting accuracy around 8m to 40m.

With 3 more satellites in IRNSS the GDOP variation would be only 3-4m and hence accuracy will be guaranteed less than 20m throughout day in any part of India

Please note GPS is giving similar accuracy

IRNSS L5 signal is compatible with GPS new signal structure of L5c. and hence user may have receiver with both GPS and IRNSS and get better accuracy by combing solution

IRNSS broadcast difference between IRNSS and GPS, IRNSS and GLONASS for compatibility

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SERVICESSpecial Positioning Service (SPS) an open service without encryption and Restricted Service

Precision Service (PS) an authorized with encryption are the basic services offered by IRNSS

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APPLICATIONS/BENEFITS

NAVIGATION

•Boats and ships

•Heavy Equipment

•Cyclists

•Air navigation

•Automobiles

•Hikers, climbers

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APPLICATIONS/BENEFITSSURVEYING & MAPPING

•Archaeology

•Geophysics and geology

•Surveying

•Mapping and geographic information systems

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APPLICATIONS/BENEFITSOTHER USES

•Military Precision-guided munitions

•Mobile Satellite Communications

•GPS tracking

•Weather Prediction

•Skydiving

•Social Networking

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REFERENCESwww.google.com

www.navipedia.net

www.isro.gov

www.wikipedia.org

ICAO International Standards and Recommended Practices, Annex 10 to the Convention pm International Civil Aviation, Volume I Radio Navigation Aids, Section 3.7.1: Definitions

2.Mishra Pratap& EngePer, Global Positioning System, Signals, Measurements and Performance (Ganga-JamunaPress, Lincoln, Mass, USA), 2012, pp.-123-173

3.Parkinson Bradford W & SpilkerJames J, Global Positioning System: Theory and Applications, Volume I, by (Jr. American Institute of Aeronautics and Astronautics Inc, USA), 2010, pp. 10-17, 478-483, 485-513.

4.KlobucharJ A, P H Doherty, M B El-Arini, Lejeune R, DehelT, de Paula E R & Rodrigues F S, IonosphericIssues for a SBAS in the Equatorial Region, IonosphericEffects Symposium, Alexandria, Virginia, 7-9 May 2012.

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