Global Poisoning System Essay -- Technology

Abstract: This paper focuses on modeling the errors which normally degrade the accuracy of Global Poisoning System (GPS). The performance of the GPS is mainly affected by ionospheric errors. SiRF Star III single frequency receiver is used for collecting and projecting datum in World Geodetic System 1984 (WGS-84) co-ordinate form. To project the ellipsoidal model onto a map model, datum conversion from WGS-84 to Universal Transverse Mercator (UTM) form is needed. The conversion introduces errors in the datum. The variation in the errors can be observed from day to night, area to area and also due to the seasonal changes. The datum is collected from Ameerpet region of Hyderabad, which is a heavily populated area with heavy traffic and tall buildings. The variation in the datum has been observed from afternoon to evening. Keywords: GPS, WGS-84, UTM, Ionospheric errors, Northings and Eastings I. INTRODUCTION The space-based global navigation satellite system that provides reliable location and time information in all weather and at all times and anywhere on or near the Earth with sub-meter accuracy is called Global Positioning System (GPS) [1]. It consists of a constellation of 28 satellites in six different orbits which give the information of the position of the user with sub meter accuracy [3]. If there are four or more GPS satellites in unobstructed line of sight with the receiver, accurate spatial co-ordinates can be obtained [2]. The datum obtained from the satellites, contain the information about the position and timing by calculating the the Keplerian orbit elements. The location information from GPS is based on the choice of coordinate system and datum [3]. The coordinate systems that are mostly used in GPS are Wor... ...ned due to the rounding up of the values in the algorithm. Works Cited [1] Bradford w. Parkinson. â€Å"Global Positioning System: Theory and Applications – vol. I and II†, American Institute of Aeronautics and Astronautics, Washington, 1996. [2] http://edu-observatory.org/gps/gps_accuracy.html, visited on 1/12/10. [3] http://www. elsevierdirect.com/companions/ 9780126836301/ appendices/ Chapter_2_ECI_ Cartesian_Coordinates_to_Kepler_Orbit_Elements_Conversion.pdf [4] http://www.squidoo.com/GPS-coordinate-systems-datums [5] Iyiade Adeniyi, â€Å"Ionospheric Error in GPS Applications† (www.ursi.org/proceedings /procGA05/pdf/GP1. 46(01062).pdf), visited on 30/10/10. [6] Ordnance Survey, â€Å"A Guide to Coordinate System in Great Britain†, (http://www.ordnancesurvey.co.uk/oswebsite/gps/docs/A_Guide_to_Coordinate_Systems_in_Great_Britain.pdf), visited on05/01/11.