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Raumfahrt - ISRO startet Navigation-Satelliten am 12.Juni 2013

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29.05.2013

Employees from the Indian Space Research Organisation (ISRO) work in the Indian Regional Navigational Satellite System (IRNSS) control room after the inauguration of the ISRO Navigation Centre at Indian Deep Space Network at Byalalu near Bengaluru-PTI

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V.Narayansami Inaugurates ISRO Navigation Centre near Bengaluru 
The ISRO Navigation Centre (INC), established at Indian Deep Space Network (IDSN) complex at Byalalu, about 40 km from Bangalore, was inaugurated yesterday (May 28, 2013) by Mr. V. Narayanasamy, Minister of State in the Prime Minister’s Office, Ministry of Personnel, Public Grievances and Pensions. INC is an important element of the Indian Regional Navigation Satellite System (IRNSS), an independent navigation satellite system being developed by India. 
Speaking on the occasion, Mr Narayanasamy appreciated the commitment and dedication of Indian space scientists in realising the objectives of the country’s space programme. The Minister also gave away various awards instituted by Astronautical Society of India (ASI) and ISRO. 
IRNSS will have a constellation of seven satellites and enables its users to determine their location and time accurately. These satellites will positioned in geostationary and inclined geosynchronous orbits 36,000 km above the earth’s surface. IRNSS coverage will extend over India and its neighborhood and the satellites are equipped with high precision atomic clocks and continuously transmit navigation signals to users. 
As the focal point of many critical operations of IRNSS, ISRO Navigation Centre is responsible for providing the time reference, generation of navigation messages and monitoring and control of ground facilities including ranging stations of IRNSS. It hosts several key technical facilities for supporting various navigation functions. 
Key to the navigation support is the time reference to which all ground systems and the satellite clocks are synchronised. This time reference is generated by the high precision timing facility located at INC. This timing facility is equipped with high stability, high precision atomic clocks to provide stable and continuous time reference to the navigation system. 
IRNSS will have a network of twenty one ranging stations geographically distributed primarily across India. They provide data for the orbit determination of IRNSS satellites and monitoring of the navigation signals. The data from the ranging/monitoring stations is sent to the data processing facility at INC where it is processed to generate the navigation messages. The navigation messages are then transmitted from INC to IRNSS satellites through the spacecraft control facility at Hassan/Bhopal. The state of the art data processing and storage facilities at INC enable swift processing of data and support its systematic storage. 
INC is connected to the ranging stations and to the satellite control facilities through two highly reliable dedicated communication networks consisting of satellite and terrestrial links. The hub for the satellite communication links is hosted at INC. 
Quelle: ISRO
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Update: 2.06.2013
Elektrik-Probleme verzögern Start von Indien ersten Navigation-Satelliten
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An electrical glitch in the rocket Saturday forced the Indian space agency to put off its first regional navigation satellite (IRNSS-1A) launch June 12 by two weeks from its spaceport at Sriharikota.

"During the checks of the polar launch satellite vehicle rocket (PSLV-C22), an anomaly was observed in one of the electro-hydraulic control actuators in the second stage," the state-run Indian Space Research Organisation (ISRO) said in a statement here.

As the replacement of the actuator will need two weeks of activity at the rocket's launch pad and the vehicle assembly area, the satellite launch has been delayed by a fortnight and will be rescheduled to June 26 from the spaceport, about 90 km from Chennai.

"Though the satellite has gone through all electrical checks after it was integrated with the rocket and was ready for propellant filling, the timely detection of the glitch has made us revisit the critical component," the statement added.

The 1,425 kg navigational satellite is intended to provide terrestrial, aerial and marine navigation services and help in disaster and fleet management across the region, after it is positioned in geostationary equatorial orbit about 36,000 km away from the earth.

"A constellation of the seven navigation satellites system will provide two types of services - standard positioning service for civilian use and restricted service, which is encrypted for authorised users (military and security)," a space official said.

In the run-up to the scheduled launch, the space agency opened May 28 a navigation centre in its Deep Space Network complex at Byalalu, about 40 km from this tech hub.

"The navigation centre will function as the main ground station for the regional navigation satellite system, as it is equipped with high precision atomic clocks and transmit navigation signals to multiple users round the clock," the official noted.

The navigation centre will also be responsible for the time reference, generation of navigation messages and monitoring and control of ground facilities, including ranging stations.

Key to the global positioning system (GPS)-based navigation support is the time reference to which all ground-based systems and satellite clocks are synchronised.

A network of 21 ranging stations located across the country will provide data for the orbit determination of the satellites and monitoring of the navigation signal.

The navigational satellites will provide an accurate real time position, navigation time (PNT) services to users in air, sea and land on a variety of platforms under all weather conditions.
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Polar Satellite Launch Vehicle (PSLV-C22) flight delayed by a fortnight
 

IRNSS-1A, the first Indian Navigation Satellite, was scheduled for launch onboard PSLV-C22 on June 12, 2013 at 01:01 hrs. from Satish Dhawan Space Centre, Sriharikota. IRNSS-1A Satellite has gone through all electrical checks and is ready for propellant filling. The PSLV-C22 vehicle was fully integrated and was undergoing electrical checks.

During the electrical checks of the launch vehicle, an anomaly was observed in one of the electro-hydraulic control actuators in the second stage. It has been decided to replace this actuator.

The replacement of the control actuator needs two weeks of activity at the Launch Pad and the Vehicle Assembly Area. Accordingly, the launch of PSLV-C22/IRNSS-1A is delayed by a fortnight with respect to the original scheduled date of June 12, 2013.

Quelle: ISRO

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