The Role of Kalman Filter in the Modelling of Gps Errors

This paper describes about the modeling of errors (like ionospheric delays, atmospheric delays, Troposphericelays, Multipath effects and dilution of precision etc.,) affecting the GPS signals as they travel from satellite to user on Earth. These errors degrade the accuracy of GPS position. An attempt is made to improve the accuracy in locating the GPS receiver by filtering the range measurements with the datum conversion between Universal Transverse Mercator (UTM) and World Geodetic System (WGS 84) using single frequency ML-250 hand held GPS receiver and smoothening of these coordinates using Kalman filter. A linear recursive filtering technique, Kalman filter is used for greater accuracy in estimating the position of user by considering the initial state of the system, statistics of system noise and measurement errors from sensor noise measurements. The results of proposed Kalman filter technique give better accuracy with more consistency and are found superior to the standard one