On the Applicability of Galileo FOC Satellites with Incorrect Highly Eccentric Orbits: An Evaluation of Instantaneous Medium-Range Positioning

Abstract

This study addresses the potential contribution of the first pair of Galileo FOC satellites sent into incorrect highly eccentric orbits for geodetic and surveying applications. We began with an analysis of the carrier to noise density ratio and the stochastic properties of GNSS measurements. The investigations revealed that the signal power of E14 & E18 satellites is higher than for regular Galileo satellites, what is related to their lower altitude over the experiment area. With regard to the noise of the observables, there are no significant differences between all Galileo satellites. Furthermore, the study confirmed that the precision of Galileo data is higher than that of GPS, especially in the case of code measurements. Next analysis considered selected domains of precise instantaneous medium-range positioning: ambiguity resolution and coordinate accuracy as well as observable residuals. On the basis of test solutions, with and without E14 & E18 data, we found that these satellites did not noticeably influence the ambiguity resolution process. The discrepancy in ambiguity success rate between test solutions did not exceed 2%. The differences between standard deviations of the fixed coordinates did not exceed 1 mm for horizontal components. The standard deviation of the L1/E1 phase residuals, corresponding to regular GPS and Galileo, and E14 & E18 satellite signals, was at a comparable level, in the range of 6.5-8.7 mm. The study revealed that the Galileo satellites with incorrect orbits were fully usable in most geodetic, surveying and many other post-processed applications and may be beneficial especially for positioning during obstructed visibility of satellites. This claim holds true when providing precise ephemeris of satellites.

Differential Inter-System Biases Estimation and Initial Assessment of Instantaneous Tightly Combined RTK with BDS-3, GPS, and Galileo

“…The GPS satellites here only restrict to the Block IIF satellites that can simultaneously transmit L1/L5 signals, while the Galileo signals come from both In-Orbit-Validation (IOV) and Full-Operation-Capability (FOC) satellites, which is the same as our previous research [7]. However, since the signals transmitted by the Galileo IOV satellites show a lower level (approximately 5 dB-HZ) of C/N0 in comparison with their FOC counterparts [31], and the C/N0 of first two FOC satellites (E14 and E18) that were injected into incorrect orbital planes could be higher than regular Galileo FOC satellites [32], only regular FOC satellites are involved in the computation of average C/N0 for Galileo.…”

Toward the 1-cm Galileo orbits: challenges in modeling of perturbing forces

“…However, the first two satellites have been accidentally placed on highly eccentric orbits (Sośnica et al 2018). Despite the fact that the two satellites are not fully suitable for navigation, they may serve for the investigation of gravitational redshift (Delva et al 2015;Herrmann et al 2018), as well as for precise positioning (Paziewski et al 2018). The following launches resulted in the increase in the number of active Galileo satellites allowing the European GNSS Agency (GSA) for announcing the operational capability in December 2016 when the part of operational services have been activated.…”

Assessment of Dual Frequency GNSS Observations from a Xiaomi Mi 8 Android Smartphone and Positioning Performance Analysis

“…This is one of the first studies that tests the multi-constellation performance of smartphone GNSS raw data in conjunction with code multipath assessment, as all the above mentioned studies analyzed only GPS observations on L1 frequency. An exhaustive exposition of the multi GNSS positioning could be found in References [14,15].…”