Use of Global Positioning System in coal mine surveying
M.S.Murthy
Dy.G.M.(Survey), SCCL
T.R.C.Reddy
Supdg.S.O., SCCL
During early 90s, Electronic Total Station and in mid 90s GPS were questions for short notes in the Mine Surveying Examination papers. May be, neither the examiner nor the examinee had thorough knowledge about these items, but only had a broad concept based on technical literatures. By now, the Electronic Total Station has grown up to be a chapter and almost all can see it physically, which is being used even by the agencies laying four-lane roads. The GPS also in course of time may assume similar importance and is likely to be available for everyone who needs it.
It is often debated at Technical Conferences, whether Global Positioning System (GPS) is useful in Mine Surveying. Mostly, it is even concluded that GPS may not be useful in Mine Surveying. The authors feel that there is a need to review the matter before it is concluded that GPS may or may not be required in Mine Surveying.
When a question "Where am I" is put to the audience, each would give his own answer and each answer looks very correct. But, the question remains still unanswered. The answer to this question in terms of Mine Surveying is the position of the speaker from the audience with reference to a meridian and datum. It is only then, the position is truly defined. The science so far being used is Azimuth for reference and MSL for datum. Unless a very detailed survey is conducted, it is absolutely impossible to establish the above two precisely. Topography, inter-visibility and distance remain as major constraints in establishing these two precisely upto the stipulated standards. The latest solution for this is Global Positioning System (GPS). Global Positioning System (GPS) is a tool which can determine on its own without any relation to the topography or otherwise the position which it occupies both in respect of meridian and datum. What all needed is open sky, minimum 4 satellites and proper selection of the method of survey.
GPS like any other precise survey instrument can be mounted on a tripod and centered on the exact point whose location is required. GPS receiver data can be transferred to a computer, which has post processing software programs. The programs calculate the positions and heights of points in the desired grid system through suitable transformation software.
The whole debate then encircles the following points:
- Initial high investment
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Accuracy
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System of coordinates
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Clear view of sky
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