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Abstract
Global Positioning System (GPS) is the most powerful and wonderful tool in modern day world, which gives position, time and movement, the three degrees of freedom, intimately connected to every individual. GPS can be called Coordinate machine, Navigation machine, Positioning machine, Time machine, Distance machine, Direction machine, Mapping machine and Leveling machine. Does it pose a security risk to individual countries? Did the terrorists use GPS to navigate to the World Trade Center and the Pentagon on September 11? What should be Indian policy towards GPS under these circumstances?
GPS also has restriction. P-code is restricted. Selective Availability was removed only on May 2nd 2000. India restricts maps, coordinates, heights, contours, gravity values, digitized maps/data, and many other important surveying and mapping products. Are these restrictions justified? Should these be changed? Are the restrictions transparent? Indian grid and the maps, on which this grid is shown, are restricted. Do these restrictions restrict development? An attempt has been made to examine all these issues in this paper.
Introduction
United States Department of Defense has given to the world GPS for navigation, positioning and time determination continuously. U. S. Government had put in place intentional restrictions on access to its signals so that accuracy of the system is limited for security considerations. Earlier there was anti-spoofing as well as selective availability (SA) to restrict accuracy of the system. Selective availability has been lifted since May 2, 2000. Anti- spoofing however continues. Accuracy of horizontal position in point positioning mode with a single receiver is limited to 15 to 20 metres, since P-code is not available to civil users. With P-code we can get accuracy of 3 to 5 metres. It is however possible to get better than 1 metre accuracy in position (latitude and longitude) by simultaneously using 2 receivers in relative or differential positioning.
If U.S.A., which is the most powerful, has put restrictions for security considerations, it is appropriate that India should also have some restrictions for dissemination of its geo-spatial data. Quote from R. Ramchandran's "Public access to geographical data" is "It only stands to reason that India devise appropriate restrictions to prevent national security-related risks. Of course any such restriction should have a rational basis. Unfortunately in the context of geographical data, the restrictions are perceived to be without much logical basis."
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