Indian Defence Review

Introduction

GSAT series of Geosynchronous Satellites, developed by Indian Space Research Organisation (ISRO) with an objective of making India self-reliant in broadcasting services (primarily Telecommunication and Television Sector) and weather forecasting (including disaster warning).  The GSAT-1 was launched on 18 April 2001.  Since then 20 GSAT satellites have been launched, of which 14 are in service.  Presently there are 10 GSAT satellites with a total of 168 transponders are  available commercially.  95 transponders are leased to broadcasters alone.  The GSAT series of satellites basically use ‘C’, extended ‘C’ and ‘Ku’ bands for uplink and downlink. 

ISRO has gone about its satellite program in a very systematic way.  It has planned its course of gradual improvement in the provision of better services and facilities in a timed and phased manner.  Accordingly, Department of Space (DoS) gave its nod to ISRO for the launch of GSAT-11, way back in 2012.  GSAT-11 is an Indian geostationary communications satellite.

GSAT-11

The original plan was to launch the GSAT-11 in May 2018.  However, due to lost communication with GSAT-6A post its successful launch in March 2018 and some glitches detected in the electrical circuit, GSAT-11 was recalled for a thorough recheck.  The fresh date of launch was set as 04 December 2108.  GSAT-11 was launched successfully from the European Space Agency space station in French Guiana at    0207 hours IST on 05 December 2018.  The launch rocket was Ariane VA 246 and after a flawless flight of 29 minutes and 07 seconds, the satellite module separated from it.

GSAT-11 is an advanced communication satellite with multi-spot beam antenna coverage over Indian mainland as well as Islands.  It brings an advantage to the user community, compared to the existing INSAT/GSAT satellite systems. With this new system architecture and the advanced technology elements employed for realization will generate a capacity of 16 GBPS for users from a single platform.  GSAT-11 is India’s most capable and top-of-the-line satellite in orbit (and ISRO’s portfolio) as on date.

GSAT-11 will carry a next-generation I-6K bus (communication satellite hub) to provide services in two widely-used wavelengths for telecommunications: the Ku- and Ka-bands.  GSAT-11 has 32 Ku-band transponders and 8 Ka-band hubs on board, making GSAT-11 three to six times more powerful than any of ISRO’s (and India’s) satellite roster today.

Salient Features

The salient features of GSAT-11 are as follows: –

Lift of Mass                           5854 kgs.

Orbital Location                    74 deg East

Spacecraft Power                 13.6 kW.

Power Source                       Two solar arrays and four antenna reflectors

Solar panels                          4 m long.

Payload                                 32 beams in Ka Band &

beams in Ku band.

Data Rate                              16 Gigabits per second (GBPS).

Satellite bus                          I-6K.

Mission Life                           15 years.

Control Center                      ISRO Master Station, Hassan.

Frequency    

Ka x Ku : Up Link   27 to 27.5 GHz; 29.5 to 30 GHz (LV & LH)

  Down Link 10.7 to 10.95 GHz; 11.2 to 11.45 GHz (LV & LH)

Ka x Ku: Up Link   12.75 to 13.25 GHz (LV & LH)

  Down Link 18.1 to 18.6 GHz; 19.7 to 20.2 GHz (LV & LH)

Coverage  –    16 Ku band beams covering Indian mainland & Island in both Polarization.

2 Ka-band beams over New Delhi & Bengaluru.

Four terrestrial gateways or ‘Hubs” located in Delhi, Ahmedabad, Bengaluru and Ranchi.  All Hubs are inter-connected to each other via Optical Fibre Network to ensure seamless connectivity.

Cost       1174 Cr.

Main highlights of the system configuration are as follows: –

• Multibeam coverage of the entire country.
• Star network-based gateway connectivity.
• ACM as fade mitigation techniques.
• Modern on-board power management techniques.

In addition, advanced onboard technologies are used to include: –

• Ground system technology with user terminals employing adaptive coded modulation. 
• Site diversity for Ka-band hub stations.
• Adaptive Coding Modulation as a fade mitigation technique.

Upgraded ISRO Satellite Profile

Presently of the 1.3 Billion Indian population, only 350 Million were covered by the footprint of various GSAT satellites.  90% of these are able to use only 2G.  Which such poor connectivity, the dream of Digital India and Smart Cities would seem implausible.  ISRO planned a series of GSAT satellites to cover entire India with overlaps for high-speed connectivity.  These included GSAT-19 (launched on 05 June 2017), GSAT-29 (launched on 14 November 2018), GSAT-11 and GSAT-20 (replacement of GSAT-6A and planned for launch in early 2019).  Besides two more satellites will be in a support role; GSAT-17 (launched on 28 June 2017) and GSAT-9 (launched on 05 May 2017, also provide data to ASEAN countries).  In effect, by mid-2019, these six satellites will cover the entire nation and 750 million people.  In all 110 Transponders will be in service and will support high data applications for enterprises and consumers.  This boost in broadband services will result in improvement in ‘Reach, Speed, and Capacity’.  The frequency reuse scheme of the system – will provide more than 200 # 36 MHz equivalent transponders.

Game Changer

GSAT-11 will act as a game changer in many ways as follows: –

• It along with other system satellites will aid Bharat Net Project aim ie, to boost access to voice and video streaming in most of rural India.  It will Bridge the communication gap between urban and rural populace.  It will boost connectivity to inaccessible Gram Panchayats.  Overall it will enhance public welfare schemes like E-banking, E-health, E-governance among others.
• Support India’s growing mobile and internet users in household, businesses and public organisations.
• Under Digital India Program it will enable implementation of ‘Smart Villages and Cities’.

Important Development for Indian Army        

The Indian Army is woefully short of bandwidth and is in dire need of high-speed data connectivity, especially along the International Border (IB), Line of Control (LC) and Line of Actual Control (LAC).  The border posts are in urgent need for data connectivity.  High-quality real-time data on enemy activity from drones and remote sensing satellites is available at data centers; the same needs to be transferred to field formations and units.  Besides, the sensor to shooter connectivity and Air Defence Control & Reporting Network too requires high-speed data transfer.  The Bharat Net Project can make it all possible.  The Indian Army should project its bandwidth requirement to ISRO / DoS for same.   

For Satellite communication, Army may go in for Very Small Aperture Terminal (VSAT).  The same is being manufactured by Bharat Electronics Limited (BEL).  Post the acquisition of VSAT (down to Battalion and Company Headquarters), the satellite communication should become the primary mode and Optical Fibre backed communication be the secondary mode.  Both together will provide seamless connectivity to each and every post; including those located in remotest areas.

Conclusion

The ISRO satellite program is on track.  As we await the launch of GSAT-20, the replacement satellite for GSAT-6A, people of India will start receiving data at a speed which we now only dream of.  India will come one step closer to establishing the dream of having ‘Smart Cities and Villages’.

1. India’S Heaviest Communication Satellite GSAT-11 Launched Successfully From French Guiana – ISRO”. 2018. Isro.Gov.In. https://www.isro.gov.in/update/05-dec-2018/india%E2%80%99s-heaviest-communication-satellite-gsat-11-launched-successfully-french.
2. GSAT-11 – ISRO”. 2018. Isro.Gov.In. https://www.isro.gov.in/gsat-11.
3. India’s Heaviest Satellite GSAT-11 Is Aloft In Space From Kourou”. 2018. The Hindu. https://www.thehindu.com/sci-tech/science/indias-heaviest-satellite-gsat-11-launched-successfully/article25668466.ece.

Courtesy: http://www.claws.in/1955/gsat-11-a-game-changer-brig-akhelesh-bhargava.html