Reference Satellite Strategic Methods to Improve Position Accuracy of Rover with Resolved Integer Ambiguities Using Linear Combination in DIRNSS System

Abstract

IRNSS is a regional system designed to procure, an accurate user position in all circumstances with 24/7 coverage. This system is used in a wide range of applications with accuracy better than 20 meters in the primary service area. The IRNSS provided position, velocity, and timing services are useful for the Indian users and also the users 1500km from the Indian frontier. The accurate positioning in the phase measurement technique depends on the resolution of ambiguities. In this paper, the main focus is on the effective resolution of ambiguities and thereby position estimation. This paper proposes a Carrier Phase (CP) differencing based Wide Lane (WL) measurement. To resolve the ambiguities, estimate the position of the WL classified methods, Single Frequency Single Difference (SFSD), Single Frequency Double Difference (SFDD), Dual Frequency Single Difference (DFSD), and Dual Frequency Double Difference (DFDD) are used. These four types are processed through the Reference Base and Reference Satellite (RBARS) algorithm to estimate the position of the user/rover. In this paper, direct amalgamate of three estimations are utilized: WL, Narrow Lane (NL), and Ionosphere Free (IF) carrier phase estimations. Using this combination, the estimations of ambiguities are determined for individual satellites by utilizing WL and NL techniques. Thereby the user/rover position is computed, by assessing these real number ambiguities. In this work, every single condition is utilized and together with the least-squares modifications, the positional errors are computed in 3D plane. The computed root mean square errors are compared for all classified methods.