GLONASS ambiguity resolution

Abstract

A new integer-estimable GLONASS FDMA model is studied and analysed. The model is generally applicable, and it shows a close resemblance with the well-known CDMA models. The analyses provide insights into the performance characteristics of the model and concern a variety of different ambiguity-resolution critical applications. This will be done for geometryfree, geometry-fixed and several geometry-based formulations. Next to the analyses of the model's instantaneous ambiguityresolved positioning and attitude determination capabilities, we show the ease with which the model can be combined with existing CDMA models. We thereby present the instantaneous ambiguity-resolution performances of integrated L1 GPS + GLONASS, both for high-grade geodetic and mass-market receivers. We also consider the potential of the single-frequency combined model for mixed-receiver processing, particularly for the case the between-receiver GLONASS pseudorange data are biased. In all cases, the speed of successful ambiguity resolution is studied as well as the precision with which positioning is determined. Software routines for constructing the model are also provided.

GLONASS FDMA data for RTK positioning: a five-system analysis

“…Generally, combining systems strongly improves the RTK positioning capabilities, as was demonstrated for GPS and Galileo (Tiberius et al 2002;Julien et al 2003;Odijk et al 2012), GPS and BeiDou (Deng et al 2014;He et al 2014;Teunissen et al 2014;Zhao et al 2014;Odolinski et al 2015b), and four-system GPS, Galileo, BeiDou, and QZSS (Odolinski et al 2015a). Such improvement can also occur when including GLONASS FDMA data (Teunissen and Khodabandeh 2019;Hou et al 2020), but it is shown that the ambiguity resolution performance can also be clearly reduced compared to the case without GLONASS.…”

“…In Teunissen (2019), a new FDMA model was introduced, in which a new set of integer ambiguity parameters is defined, that enables integer ambiguity resolution also for GLONASS. The performance of this model with GLONASS and GPS data was first demonstrated for short baseline positioning and direction finding in Teunissen and Khodabandeh (2019), and for short to long baseline positioning in Hou et al (2020). As shown in Teunissen and Khodabandeh (2019), the FDMA model is much weaker than the CDMA model in terms of the ambiguity resolution performance so that, for instance, GLONASS only reliable single-epoch ambiguity resolution is often not possible on short baselines with dual-frequency observations as for CDMA systems.…”

“…The performance of this model with GLONASS and GPS data was first demonstrated for short baseline positioning and direction finding in Teunissen and Khodabandeh (2019), and for short to long baseline positioning in Hou et al (2020). As shown in Teunissen and Khodabandeh (2019), the FDMA model is much weaker than the CDMA model in terms of the ambiguity resolution performance so that, for instance, GLONASS only reliable single-epoch ambiguity resolution is often not possible on short baselines with dual-frequency observations as for CDMA systems. Teunissen (2019) and Teunissen and Khodabandeh (2019) pointed out the importance of partial ambiguity resolution (PAR) when using GLONASS data.…”

“…As shown in Teunissen and Khodabandeh (2019), the FDMA model is much weaker than the CDMA model in terms of the ambiguity resolution performance so that, for instance, GLONASS only reliable single-epoch ambiguity resolution is often not possible on short baselines with dual-frequency observations as for CDMA systems. Teunissen (2019) and Teunissen and Khodabandeh (2019) pointed out the importance of partial ambiguity resolution (PAR) when using GLONASS data. They showed that even with the geometry-fixed model, which is the strongest possible model that assumes the relative receiver satellite geometry known, PAR is required for a high ambiguity resolution reliability, thus implying the necessity of PAR for any other model.…”

An Improved Relative GNSS Tracking Method Utilizing Single Frequency Receivers

“…It should be mentioned here that we did not use the new GLONASS FDMA model for giving out the reference value. However, the new model can be used to give integer ambiguity solutions with high success rates, and now and in the future it offers an excellent opportunity for the new integer estimable GLONASS model to utilize combined FDMA−CDMA signals [38,39].…”