Ionospheric STEC and VTEC constraints for fast PPP

Abstract

Significant initialization or convergence time of PPP is a limiting factor for many applications. Recent studies have indicated that external ionospheric information can be applied to provide a tight constraint to reduce the correlation between the position parameters and the ionosphere to shorten PPP long convergence time. However, receiver DCB is one challenge to separate from STEC. Receiver DCB is often neglected and taken for granted that it can be absorbed by the receiver clock parameter. In this paper, we critiqued the ionospheric STEC and VTEC constrained PPP models separating receiver DCB by taking advantage of the ionospheric information from a nearby station and GIM products. The results show that the improvements of positioning accuracy for ionospheric STEC and VTEC constrained PPP models are about 67 and 26% after a convergence time of 1 min. The convergence time is significantly reduced with the ionospheric constraints from a nearby station, while the performance of convergence time with GIM depends on the quality of GIM.