Impact of dilution of precision for position computation in Indian regional navigation satellite system

Abstract

The System of seven satellites, Indian Regional Navigation Satellite System (IRNSS) will provide Special Positioning Service (SPS) and Precision Service (PS) towards the Indian subcontinent. In Positioning Navigation Timing (PNT) application, measurement is affected by some intentional and unintentional sources of error. This Measurement also depends on the volume of tetrahedron created by the geometry of measuring satellites. The Satellites geometry is measured by single dimensionless numbers called GDOP. Lower the GDOP value, the better the satellite Geometry, hence the position measured by the system is more precise. Currently, IRNSS system has six active satellites in an orbit. In this paper performance analysis of IRNSS, GPS and IRNSS+GPS are investigated by computing the GDOP due to all satellites in view. The performance analysis is done using ACCORD IRNSS receiver which is provided by SAC, ISRO, Ahmedabad. The dual frequency IRNSS receiver of SVNIT, SURAT (21.16° Lat., 72.78° Long.) is explored for best GDOP configuration and position determination over the Indian subcontinent.