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Scope for application of GPS in Indian coal industry  A . Venkateshwar Singareni Collieries Company Ltd Andhra Pradesh, India. sccl@ap.nic.in
Introduction Before we get onto the core issue , let us try to recap as to when and where GPS started. The first one called NAVSTAR GPS (Navigation Satellite Timing and Ranging Global Positioning System) was (and still is) a satellite-based radio navigation and surveying system providing precise three dimensional position, navigation and time information to suitably equipped users everywhere on a continuous basis. The system consists of 24 satellites including three active spares , placed in near circular orbits in six orbital planes of 55 o inclination at height of about 20,200 km. There are often more than 24 operational satellites as new ones are launched to replace older satellites. The orbit altitude is such that the satellites repeat the same track and configuration over any point approximately every 24 hours. The satellites have 12-hour periods so that atleast 4 satellites are available for observations for positioning on ground, sea and air at any time throughout the year anywhere in the world. GPS provides specially coded satellite signals that can be processed in a GPS receiver, enabling the receiver to compute position, velocity and time. Signals from four satellites are required to compute the four dimensions of X, Y, Z (position) and Time at any point on Earth. GPS was developed and funded by the U. S. Department of Defence (DOD) during early 1970s primarily for military applications with limited access to civilian users. Virtually all of the development of GPS equipment was under contract from the DOD (US). Many of the contractors to the government also had commercial involvement in similar technologies, especially receivers. This meant that by the early eighties, commercial interest in GPS began to blossom. By 1990, although the system was not fully implemented, it was sufficiently reliable to make general commercial and even personal use viable. The system has now been completed and is in full commercial use GPS Applications GPS receivers have been developed which observe signals transmitted by the satellites and achieve upto 2cm accuracy horizontally and 3cm vertically anywhere on earth’s surface. They have the following advantages over conventional methods of navigation or surveying:
Time and frequency dissemination, based on the precise clocks on board the satellites and controlled by the monitor stations, is another use for GPS. Astronomical observatories, telecommunications facilities, and laboratory standards can be set to precise time signals or controlled to accurate frequencies by special purpose GPS receivers. Research projects have used GPS signals to measure atmospheric parameters.Now, there is an increasing confidence in adapting GPS to other commercial and social applications. GPS Accuracy GPS achieves integrity and protects users against system anomalies and failures by relying on satellite self-checks and , as well as signal assessment by users. Thus, GPS has both integral and independent mechanisms to assure integrity.Augmented GPS systems have additional built-in integrity monitoring that can benefit GPS users. Differential GPS (DGPS) and Real time Kinematic (RTK) systems, such as the network operated by the U.S. Coast Guard (USCG), use an onsite integrity monitor to check satellite-signal validity and provide an independent assessment of satellite health. Because of the real-time capability, continuous availability and the high accuracy potential, GPS usage is very broad and is still growing. GPS reliability Since GPS user equipment does not transmit, there is no limit to the number of GPS receivers that can be used on the system. There are no licensing fees for the receivers and no requirement to register their ownership. There are no restrictions on the use of GPS for positioning and the received data/information can be stored and re-transmitted, if required. Background on Coal Industry Coal is the primary source of power generation in many countries of the world, and is the most abundant, widely distributed, safe and economical fossil fuel available to meet the escalating energy demand, providing around 33% of global primary energy needs and generating 36% of world’s electricity at present. Coal continues to be the pre-dominant energy source in India contributing to about 63% of its total energy needs. Coal mining in India commenced in 1774 and has come a long way from a production level of 6.19 Mt. in 1900 to about 310 Mt. in 2000-01. Coal production increased rapidly after nationalisation of coking coal mines in 1972 and non-coking coal mines in 1973 undertaken to ensure coal conservation and scientific development of coal resources in the country. Public sector coal companies contribute 98% of India’s coal production, of which Coal India Limited accounts for 88% and Singareni Collieries Company Limited(SCCL) for 10%. Other companies like DVC, IISCO, TISCO and captive mining firms make up the balance. Predominance of surface mining in the Indian coal industry with a share of over 80% and 54% respectively of total production in Coal India Limited and SCCL, calls for insightful analysis of the means and methods for upgrading the production and performance of surface mining systems in the 21st century. Even if there are surface mining systems of variegated sizes and sophistication, there is no doubt whatsoever that surface mining systems from small scale to medium scale and mega-sized mines, would call for significant inputs of new technology to be cost effective, environmentally friendly and meet the production requirements. In striving for new levels of performance in the competitive environment of the 21st century, technology will be the principal lever for change, where information technology (IT) will play a key role. Benchmarking of surface mining operations world-wide reveal a yawning gap between the performance capability of the best of the mines and the worst of the mines and there exists an imperative need to bridge this gap. Since, the scale of operations in opencast coal mines in India has grown by leaps and bounds, the conventional methods of surveying, planning and operating the mines would have to be upgraded to meet the requirements. A whole host of leading edge technology products and systems for effective management of surface mines have evolved in the past decade.
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