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| The uses of satellite technology in disasters such as Srinagar floods | | | NIKHIL GUPTA | 1/24/2015 8:13:30 PM |
| A satellite is basically a self-contained communications system with the ability to receive signals from Earth and to retransmit those signals back with the use of a transponder which is an integrated receiver and transmitter of radio signals . A satellite is launched into orbit by a rocket that moves at very high speed of more than 11.2 meters per second . This speed is necessary to defeat the gravitational pull of the earth . The satellite operates in a hostile space environment where it can be subject to radiation and extreme temperatures for its projected operational life. In addition, satellites have to be light, as the cost of launching a satellite is quite expensive and based on weight. To meet these challenges, satellites must be small and made of lightweight and durable materials. They must operate at a very high reliability . The main components of a satellite consist of the communications system, which includes the antennas and transponders that receive and retransmit signals, the power system, which includes the solar panels that provide power, and the propulsion system, which includes the rockets that propel the satellite. A satellite needs its own propulsion system to get itself to the right orbital location and to make occasional corrections to that position. A satellite in geostationary orbit can deviate up to a degree every year from north to south or east to west of its location because of the gravitational pull of the Moon and Sun. A satellite has thrusters that are fired occasionally to make adjustments in its position. A satellite's life span is determined by the amount of fuel it has to power these thrusters. Once the fuel runs out, the satellite eventually drifts into space and out of operation, becoming space debris. A satellite needs internal power to be able to operate its electronic systems and communications payload. The main source of power is sunlight which is harnessed by the satellite's solar panels. A satellite also has batteries on board to provide power when the Sun is blocked by Earth. Communication satellites range from microsatellites to large satellites . Satellites operate in three different orbits i.e. Low Earth Orbit (LEO), medium Earth orbit (MEO), and geostationary or geosynchronous orbit (GEO). LEO satellites are positioned at an altitude between 160 km and 1,600 km above Earth. MEO satellites operate from 10,000 to 20,000 km from Earth. It is important to note that the satellites do not operate between LEO and MEO because of the inhospitable environment for electronic components in that area which is caused by the Van Allen radiation belt . Van Allen radiation belt is a doughnut-shaped zone of highly energetic charged particles trapped at high altitudes in the magnetic field of Earth. It was named after James A. Van Allen, the American physicist who discovered them . The Van Allen belt is most intense over the Equator and is effectively absent above the poles .
GEO satellites are positioned 35,786 km above Earth where they complete one orbit in 24 hours and thus remain fixed over one spot. It only takes three GEO satellites to provide global coverage, while it takes 20 or more satellites to cover the entire Earth from LEO and 10 or more in MEO. In addition, communicating with satellites in LEO and MEO requires tracking antennas on the ground to ensure seamless connection between satellites. A signal that is bounced off a GEO satellite takes approximately 0.22 second to travel at the speed of light from Earth to the satellite and back. This delay poses some problems for applications such as voice services and mobile telephony. Therefore, most mobile and voice services usually use LEO or MEO satellites to avoid the signal delays resulting from the inherent latency in GEO satellites. GEO satellites are usually used for broadcasting and data applications because of the larger area on the ground that they can cover. Requirements for a satellite to be geostationary include satellite's revolutionary direction to be same as that of the earth, i.e. from west to east. Further the time period of satellite's revolution must be same to the time period of the rotation of earth along its polar axis, which is equal to 24 hours and the equatorial plane of earth must be coplanar with the orbital plane of the satellites revolution . Various kinds of Satellites, including communications, meteorology, remote sensing and geophysics satellites are useful tools in disaster prevention, preparedness and relief. They already provide operational capability for storm warnings and search-and-rescue efforts. Other capabilities are improved flood prediction and global mobile communications during relief . Still others, such as earthquake prediction, require considerable research. Close cooperation and communication between space technologists and disaster-management specialists will be needed in guiding research and designing and testing satellite systems solely for the purpose of disaster management and saving human lives in such disasters . Satellite phones boldly go where cell phones can't . They let you make phone calls from almost anywhere because their primary infrastructure is literally out of this world. Satellite phones don't rely on a terrestrial cell phone network. Instead they beam their data directly to and from satellites orbiting Earth. Now a days there is an availability of DSPT that stands for "Digital Satellite Phone Terminal " in general what we call as "Satellite Phone". It is useful in remote areas where you do not have landline or cell phone signals . DSPT(Digital Satellite Phone Terminal) comes with 1.2 Meter Satellite Antenna (in Ku Band), Solar Photovoltaic Panel and various other accessories that make it a complete system to have communication virtually at any place . It is a common knowledge that our armed forces operate at very tough terrains and at very high altitudes . It is not possible to have other terrestrial communication systems at such places . The DSPTs provide a reliable communication at such places and provide relief to our army personnel who can talk with their families even while working on the border posts . It is again a common knowledge that during the disasters such as floods , earthquakes or any such disaster the first requirement for the administration in government is to have a communication link so as to coordinate the relief measures on a large scale . I am reminded of the recent devastating floods in the Srinagar region where the floods caused so much damage that the entire civil communication system was devastated . Basically the civil communication system now a days consists of a digital switch which we commonly call as a telephone exchange and the huge integrated network of telephone cables , mobile towers , mobile switching centers etc . This system makes it possible to provide communication link to all those who have access to the fixed telephone instruments or the mobile telephone instruments . But the heart of the system is the digital switch in the case of the landline and a mobile switching centre (MSC) in the case of the mobiles or the cell phones . The heart or the digital switch requires a continuous power supply and that is why the power plants of these digital switches and MSCs are of "no Break " type i.e. the power supply cannot fail . In other words there should be continuous power supply to the digital switches . This is made possible with the help of an integrated system of mains power supply , two sets of Battery Banks and also two sets of the Engine Alternators . This no break power plant provides continuous power to the digital switches so that there is continuous communication available to the people . It is also important to note that while the digital switches and MSCs can be at different floors of a building , the power plant is mostly at the ground floor of the building . During the Srinagar floods the flood waters inundated the ground floors and thus tripped the power plants and without the power supply the digital switches and the MSCs also tripped . At that time the only hope for the establishment of the communication was through the use of the satellite phone or the DSPT . It is heartening to note that the present government of India headed by honorable Narendra Modi Ji rose to the occasion and with the active help from the armed forces the situation in Srinagar was tackled and quite substantial number of satellite phones were provided in that region to help administration coordinate relief measures and to also allow people and the tourists trapped there to talk to their relatives and friends . I read an article of previous Chief Minister respectable Omar Abdullah ji depicting the Srinagar flood condition and how his administration desperately needed communication in the first few days of the floods . I propose that since our state is disaster prone area there should be adequate number of satellite phones available at each district headquarters so that during the disasters the relief measures do not fail for want of the communication link . Further the satellite phones or the DSPT should be kept at such a place which is comparatively safe . It should not happen that the satellite phone is appropriated by the senior most officer of the district who may keep it in his office . For the real use of such a communication terminal it should be kept at a place which is comparatively safe and which can be accessed easily during the disasters .
The contents of the article have no bearing on any person or any organization and the author is guided by the motto " THE ROYALE GUPTA WARRIORS NEVER FIGHT FOR THEMSELVES BUT FIGHT FOR A BIGGER CAUSE " . Vande Matram and Jai Hind . Author can be contacted at [email protected] |
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