A sequential and partial ambiguity resolution strategy for improving the initialization performance of medium-baseline relative positioning

Abstract

Ionosphere products that are relatively precise are available thanks to the efforts of the International GNSS Service (IGS), and it might be possible to obtain a high success rate for the fixed integer ambiguities for medium-or longerbaseline ambiguity resolution (AR) using the ionosphere products as a priori information constraints. In this study, we used the IGS precise ionosphere products as a priori information before forming double-difference (DD) measurement equations using only original observables in a mid-range relative positioning and estimated the ionosphere residuals explicitly after DD. Furthermore, we proposed a sequential and partial ambiguity resolution (SPAR) strategy under the integer least square condition to realize fast and reliable AR. To demonstrate our proposed strategy, we randomly selected seven baselines ranging from 30 to 111 km and undertook positioning in a post-processing mode using real GPS dual-frequency data. According to the results, the SPAR strategy has a faster convergence process compared with batch AR. For instance, the convergence time with >90 % cumulative frequency percentage (probability) for 30, 40, 56, 66, 80, 95, and 111 km baselines was advanced by 55, 50, >75, 85, >110, 65, and >35 epochs, respectively, with a 30-s sample interval. By considering ionospheric correction before DD, we found further improvement in the initialization performance with the use of the SPAR strategy.

Enhanced wide-area multi-GNSS RTK and rapid static positioning in the presence of ionospheric disturbances

“…The first group of such algorithms implements and employs empirical ionospheric models, such as International Reference Ionosphere (IRI), Klobuchar, NeQuick and Neustrelitz, however, due to the high level of spatiotemporal generalization, they do not meet the requirements of rapid precise positioning even for quiet conditions. Another approach, mainly applied in post-processing applications, utilizes GNSS-based global ionospheric maps (Zhang et al 2016). These maps, however, feature insufficient spatio-temporal resolution to capture the disturbances during high ionospheric activity (Park et al 2016).…”

A Fusion Water Quality Soft-Sensing Method Based on WASP Model and Its Application in Water Eutrophication Evaluation

“…According to the statistical analysis requirements in the selection of evaluation indexes, generally take [31] ≥ 85%.…”