A comparative assessment of online GNSS processing services for geodetic control: insights from the ethiopian network

Abstract This study compares four online GNSS processing services AUSPOS, TrimbleRTX, OPUS, and CSRS-PPP using 72-h static GNSS data from 12 geodetic control stations in Ethiopia. Observations collected with a Leica GS10 receiver were processed by each service and evaluated against a high-precision BERNESE reference solution. One-way ANOVA showed no statistically significant differences in mean coordinates at the 95 % confidence level ( p > 0.05). However, practical precision varied notably among services, with coordinate discrepancies ranging from millimeter-level agreement to maximum differences of 44 mm (X), 30 mm (Y), and 20 mm (Z) between service pairs. CSRS-PPP and AUSPOS showed the closest agreement with the reference (mean 3D differences of 1.0 cm and 2.1 cm, respectively), while TrimbleRTX exhibited consistent systematic biases requiring datum transformation. Although statistically comparable, CSRS-PPP and AUSPOS are recommended for high-accuracy geodetic applications due to their superior consistency.