Communication and Meteorological Satellite System

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Communication and Meteorological Satellite System

INSAT System
Established in 1983, the Indian National Satellite (INSAT) is the largest domestic communication satellite systems in the Asia Pacific Region with nine satellites in operation – INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT and INSAT-4A. It is a joint venture of the Department of Space, Department of Telecommunications, India Meteorological Department, All India Radio and Doordarshan. The overall coordination and management of INSAT system rests with the Secretary-level INSAT Coordination Committee. The latest satellite in the series, INSAT-4B, is getting ready for its launch from Kourou in French Guyana shortly and will give further boost to INSAT capability, especially for Direct-To-Home (DTH) television broadcast.

Satellites in Service
INSAT-2E: The last of the five satellites in INSAT-2 series, INSAT-2E is now in its eighth year of service.

It carries the following payloads:
• Seventeen C-band and lower extended C-band transponders providing zonal and global coverage with an Effective Isotropic Radiated Power (EIRP) of 36 dBW.
• A Very High Resolution Radiometer (VHRR) with imaging capacity in the Visible (0.55-0.75 micron), Thermal Infrared (10.5-12.5 microns) and Water Vapour (5.7-7.1 microns) channels and providing 2x2 km, 8x8 km and 8x8 km ground resolution respectively.
• A Charge Coupled Device (CCD) camera providing 1x1 km ground resolution in the Visible (0.63-0.69 micron), Near Infrared (0.77-0.86 micron) and Shortwave Infrared (1.55-1.70 micron) bands.
Under an agreement with the International Telecommunications Satellite Organisation (INTELSAT), eleven 36 MHz equivalent units of C-band capacity on INSAT-2E have been leased to INTELSAT.

INSAT-3 Series
Of the five satellites, INSAT-3A through INSAT-3E, planned under INSAT-3 series, four satellites – INSAT-3A, INSAT-3B, INSAT-3C and INSAT-3E – have already been launched and are providing satisfactory service.

The multipurpose satellite, INSAT-3A, was launched by Ariane in April 2003. It is located at 93.5 degree East longitude. The payloads on INSAT-3A are as follows:
• 12 Normal C-band transponders (9 channels provide expanded coverage from Middle East to South East Asia with an EIRP of 38 dBW, 3 channels provide India coverage with an EIRP of 36 dBW and 6 Extended C-band transponders provide India coverage with an EIRP of 36 dBW).
• 6 Ku-band transponders provide India coverage with EIRP of 48 dBW.
• A Very High Resolution Radiometer (VHRR) with imaging capacity in the Visible (0.55-0.75 microns), Thermal Infrared (10.5-12.5 microns) and Water Vapour (5.7-7.1 microns) channels, provide 2x2 km, 8x8 km and 8x8 km ground resolutions respectively.
• A CCD camera provides 1x1 km ground resolution, in the Visible (0.63-0.69 micron), Near Infrared (0.77-0.86 micron) and Shortwave Infrared (1.55-1.70 micron) bands.
• A Data Relay Transponder (DRT) having global receive coverage with a 400 MHz uplink and
4500 MHz downlink for relay of meteorological, hydrological and oceanographic data from unattended land and ocean-based automatic data collection-cum-transmission platforms.
• A Satellite Aided Search and Rescue (SAS&R) payload having global receive coverage with
406 MHz uplink and 4500 MHz downlink with India coverage, for relay of signals from distress beacons in sea, air or land.

Launched in March 2000, INSAT-3B is collocated with INSAT-2E at 83 degree East longitude. It carries 12 Extended C-band transponders and three Ku-band transponders that have coverage over the Indian region. INSAT-3B also incorporates a Mobile Satellite Services (MSS) payload with forward link between the hub and mobile station operating in CxS band and return link between the mobile station and the hub operating in SxC band.

Launched in January 2002, INSAT-3C is positioned at 74 degree East longitude. INSAT-3C payloads include 24 Normal C-band transponders providing an EIRP of 37 dBW, six Extended C-band transponders with EIRP of 37 dBW, two S-band transponders to provide BSS services with 42 dBW EIRP and an MSS payload similar to that on INSAT-3B. All the transponders provide coverage over India.

KALPANA-1 is an exclusive meteorological satellite launched by PSLV in September 2002. It carries VHRR and DRT payloads to provide meteorological services. It is located at 74 degree East longitude.

Launched in September 2003, INSAT-3E is positioned at 55 degree East longitude and carries 24 Normal C-band transponders provide an edge of coverage EIRP of 37 dBW over India and 12 Extended C-band transponders provide an edge of coverage EIRP of 38 dBW over India.

Launched by GSLV in May 2003, GSAT-2 is located at 48 degree East longitude and carries four Normal C-band transponders to provide 36 dBW EIRP with India coverage, two Ku-band transponders with 42 dBW EIRP over India and an MSS payload similar to those on INSAT-3B and INSAT-3C.

Configured for audio-visual medium employing digital interactive classroom lessons and multimedia content, EDUSAT was launched by GSLV in September 2004. Its transponders and their ground coverage are specially configured to cater to the educational requirements. The satellite carries a Ku-band transponder covering the Indian mainland region with 50 dBW EIRP, five Ku-band spot beam transponders for South, West, Central, North and North East regional coverage with 55 dBW EIRP and six Extended C-band transponders with India coverage with 37 dBW EIRP.

EDUSAT is positioned at 74 degree East longitude and is collocated with KALPANA-1 and INSAT-3C.

Launched in December 2005 by the European Ariane launch vehicle, INSAT-4A is positioned at 83 degree East longitude along with INSAT-2E and INSAT-3B. It carries 12 Ku-band 36 MHz bandwidth transponders employing 140 W TWTAs to provide an EIRP of 52 dBW at the edge of coverage polygon with footprint covering Indian main land and 12 C-band 36 MHz bandwidth transponders provide an EIRP of 39 dBW at the edge of coverage with expanded radiation patterns encompassing Indian geographical boundary, area beyond India in southeast and northwest regions.

Launched on board PSLV-C6 as a co-passenger of CARTOSAT-1 in May 2005, HAMSAT is an application-specific micro-satellite designed to provide satellite based Radio Amateur Services to Indian as well as international HAM (Amateur Radio Operators) community. The 43.5 kg HAMSAT carries Linear Mode-B (UHF/VHF) transponders – one Indian and the other designed by a Dutch Amateur Radio Operator from Higher Technical Institute, Venlo, The Netherlands.

Forthcoming Satellites
Configured with payloads identical to that of INSAT-4A, INSAT-4B will carry 12 Ku-band and 12 C-band transponders to provide EIRP of 52 dBW and 39 dBW respectively. Two Tx/Rx dual grid offset fed shaped beam reflectors of 2.2 m diameter for Ku-band and 2 m diameter for C-band are used. INSAT-4B is intended to augment the high power transponder capacity over India in Ku-band and over a wider region in C-band.

INSAT-4B in its final stages of assembly

INSAT-4B is planned for launch on board the European ARIANE-5 launch vehicle in the first quarter of 2007. It will be co-located with INSAT-3A at 93.5 degree E longitude.

During the year, integration of payload and main frame systems have been completed. Integrated spacecraft tests have also been completed. New electronics scheme has been configured. The spacecraft has undergone dynamic and radiation tests and has been transported to Kourou in French Guyana for its launch.

Fabrication of INSAT-4CR was taken up during the year as a replacement for INSAT-4C, the launch of which was unsuccessful in July 2006. INSAT-4CR will be identical to INSAT-4C with 10/12 Ku-band transponders with an EIRP of 51.5 dBW. It will
be positioned at 74 degree E longitude co-located with INSAT-3C, KALPANA-1 and GSAT-3.
During the year, all layouts have been finalised and subsystems are under fabrication. All electronics packages are under wiring and testing. Spacecraft structure is in the final stages of integration. Solar panel substrates have also been realised and solar cell bonding is in progress. Payload system elements are under realisation.

GSAT-4 is envisaged as a technology demonstrator. Its communication payload consists of multi-beam Ka-band bent pipe and regenerative transponder and navigation payload in C, L1 and L5 bands.

GSAT-4 will also carry a scientific payload, TAUVEX, comprising three Ultra-Violet band telescopes developed by Tel Aviv University and Israel space agency (ELOP) for surveying a large part of the sky in the 1400-3200 A wavelengths.

GSAT-4 employs several new technologies like electric propulsion with four stationary plasma thrusters, Bus Management Unit (BMU), miniaturized dynamically tuned gyros, 36 AH Lithium ion battery, 70 V bus for Ka-band TWTAs, on-board structural dynamic experiment, thermal control coating experiment and vibration beam accelerometer. GSAT-4 is planned for launch by GSLV during 2007-08.

Ka-band Segmented Multi-beam Antenna and Feed Systems for GSAT-4

During the year, north and south equipment panel have been realised and TAUVEX engineering and structural model interface validation tests completed. Preliminary design review of Ka-band shaped segmented multi beam antenna, electrical and mechanical systems have been completed.

Antenna tests of INSAT-4B in the Compact Antenna Test Facility at ISITE

INSAT-3D Meteorological Sounder under integration and test

Configured as an exclusive C-band communication satellite, GSAT-5/INSAT-4D will carry
12 normal C-band transponders and six extended C-band transponders with wider coverage
in uplink and downlink coverage over Asia, Africa and Eastern Europe as well as zonal coverage with minimum of 35 dBW EIRP. It will be launched on board GSLV during 2008-09 and positioned at 82 deg E longitude.

During the year, GSAT-5/INSAT-4D payload configuration has been finalised. Spacecraft antenna configuration has been finalised to include two deployable shaped reflectors and one single shell shaped reflector.

GSAT-6/INSAT-4E will carry digital multimedia broadcasting payload. The satellite will cover entire India through five S-band spot beams using SxC and CxS transponders. The C-band coverage for the feeder link will have India coverage. The satellite is planned to be launched during 2009-10 by GSLV.

GSAT-7/INSAT-4F is proposed as a multi-band satellite carrying payloads in UHF, S-band, C-band and Ku-band. It is planned to be launched during 2010-11 by GSLV.

GSAT-8/INSAT-4G is proposed as a Ku-band satellite carrying 18 transponders similar to
that of INSAT-4A and INSAT-4B. It will also carry 2 BSS transponders and a GPS Aided
Geo Augmented Navigation (GAGAN) payload. The satellite is expected to be launched during 2009-10.

INSAT-3D is a meteorological satellite planned to be launched in the 2008-09. The satellite has many new technology elements like star sensor, micro stepping Solar Array Drive Assembly (SADA) to reduce the spacecraft disturbances and Bus Management Unit (BMU) for control and telecomm and/telemetry function. It also incorporates new features of bi-annual rotation and Image and Mirror motion compensations for improved performance of the metrological payloads.

W2M is being developed and built for EUTELSAT, jointly with EADS-Astrium under a contract through ANTRIX. EADS Astrium is the prime contractor in charge of overall programme management and will build the communications payload. ANTRIX/ISRO will build the satellite bus, based on the flight proven I-3K model, integrate and test the spacecraft. ISRO will also be in charge of early in-orbit operations.

W2M will operate typically 26 transponders in Ku-band and up to 32 depending on operational modes, for a designed operational lifetime of 15 years. W2M displays great flexibility to operate a wide range of services from television broadcasting to data networks and broadband. It will have a fixed beam coverage for Europe, North Africa and Middle East and a steerable beam which can be re-oriented in orbit according to market requirements, notably towards Africa and central Asia.

W2M is to be delivered to Eutelsat for launch in the second quarter of 2008.
During the year the tasks completed include: equipment qualification status review, material and process control board review for the declared materials list, finalisation of reflector configurations and interfaces, preparation of interface reference drawings, baseline design review and finalisation and release of solar array mechanisms components for fabrication.

Satellite Navigation

IRNSS concept


Location of IRNSS satellites

The Government has approved the Indian Regional Navigation Satellite System (IRNSS).
It consists of a constellation of seven satellites – three in Geo Stationary Orbit (GSO) and four in Near-GSO. Indian Regional Navigation Satellite System (IRNSS) management structure for system implementation has been established and detailed system definition (space segment and ground segment) work has begun. IRNSS is expected to provide
position accuracies comparable to the declared position accuracies by other global constellations in a region centred over India and extending to adjoining areas. It is expected to implement this regional navigation system in about 5 to 6 years. IRNSS satellites will transmit ranging codes and navigation data in S and L-5 bands. The Navigation software and user receiver specifications are being finalized.

C-band upconverter and Surface Acoustic Wave (SAW) Filter for GAGAN


The Technology Demonstration System (TDS) phase of the Indian Satellite-Based Augmentation System GAGAN is coming to a close. Eight Indian Reference Stations, one Master Control Centre (MCC) and one Indian Land Uplink Station have been commissioned. The Preliminary System Acceptance Test was successfully carried out in May 2006. TheFinal System Acceptance Test is scheduled to be completed in early 2007.

The first navigation payload flight model is almost ready and it is proposed to be flown on GSAT-4 expected to be launched in 2007. Two more payloads will be subsequently flown on GSAT-8 and GSAT-9.

ANUSAT, a 35 kg micro-satellite, is being designed by Anna University, Chennai. The main objective is to involve universities in building micro satellites as a means to promote and encourage intra-disciplinary technologies with the help of ISRO.

ANUSAT carries a digital store and forward payload for amateur communication. In addition, a number of technological payloads like digital receiver and turbo coder, MEMS-based gyro and magnetic field sensor are planned to be flown on board. Structure, solar panels, chemical battery, sensors and actuators will be supplied by ISRO. The payloads and the other satellite subsystems are designed and fabricated at Anna University.

The configuration of this satellite has been finalised and preliminary design review completed. Breadboard design of core electronic systems has also been completed. The flight model is expected to be realised during 2007-08.

Advanced Technology Development
Development of stratospheric platforms for broadband communication applications are being studied involving the use of airship. Other developments in satellite technology include smart structures, large unfurlable antenna for GSAT-6 spacecraft, robatics, etc, have continued during the year.

Master Control Facility (MCF)
MCF continue to provide in orbit operation of geostationary satellites during the year. It is
now controlling nine on orbit satellites – INSAT-2E, INSAT-3B, INSAT-3C, INSAT-3A, INSAT-3E, INSAT-4A, KALPANA-1, GSAT-2 and EDUSAT. Seven of these satellites are controlled from MCF, Hassan and two (EDUSAT and INSAT-3B) from MCF Bhopal. MCF, Hassan has an integrated facility consisting of seven satellite control earth stations. MCF, Bhopal, is configured with 11 m diameter full motion antenna and three 7.2 m diameter limited motion antenna. During the year one limited motion antenna terminal operating in C-band was added to MCF, Bhopal.

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