Datum Definition in the Long Range Instantaneous RTK GPS Network Solution

Israel Kashani, Pawel Wielgosz, Dorota Grejner-Brzezinska

The Ohio State University, CEEGS, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210-1275.
The Ohio State University, CEEGS, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210-1275; Technion - Israel Institute of Technology.

DOI:                 

Abstract

This paper presents the multiple reference station approach to wide area (and regional) instantaneous RTK GPS, implemented in the MPGPSTM (Multi Purpose GPS Processing Software) software, developed at the Ohio State University. A weighted free-net approach (WFN) was applied in the instantaneous RTK software module, which enabled optimal estimation of the rover coordinates, properly reflecting the accuracies of the observations and the coordinates of the CORS stations. The effect of using the distance-dependent weighting scheme in the WFN approach on the final rover solution is analyzed. The influence of the different weights was studied by introducing the distance-dependent weights as a function of the CORS station separation L to the rover (1/L2). The results show that almost 100% of the differences between the computed horizontal rover coordinates and the known reference coordinates are below a decimeter, and 95% of the differences in the vertical coordinate are below 20 cm, when using the suggested approach. In addition, the accuracy analysis of two other solutions, with different datum definition (minimum constraint and over-constrained), is presented. This analysis verifies the suitability of the stochastic models used in the RTK module and the rigorous approach, taking into account inter-baseline correlation as well as the correlation in-between each baseline component.

Keywords

RTK, GPS, Datum Definition

Conflicts of Interest

The authors declare no conflicts of interest.

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