Assessment of errors in NavIC observables for stationary receivers

Abstract

Our objective in this paper is to assess all errors in NavIC's pseudorange so that they can be mitigated or accounted for appropriately in the dynamics model to achieve high-accuracy navigation. Multipath errors in the L5 and S1 pseudoranges are different; hence, oscillatory multipath is removed using sidereal repeatability for these frequencies separately for accurate iono delay estimation. Iono delay estimates using uncompensated pseudoranges are 7-m greater than the normal night time estimates due to multipath. When oscillations are removed, the difference reduces to (Formula presented.) 3 m. Dual-frequency estimates using code phase are within two-sigma of the grid-based estimates. A comparison of the NTCM-GL and Klobuchar iono delay estimates is presented for the low-latitude region in India. The ephemeris line-of-sight errors blended with the unknown multipath bias errors are estimated using a low-pass filter and are found to lie at the edges of the two-sigma signal-in-space error. © 2020 Institute of Navigation