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TitleModel comparison for GLONASS RTK with low-cost receivers
AuthorBanville, S; Collins, P; Lahaye, F
SourceGPS Solutions 22, 52, 2018.,
Alt SeriesNatural Resources Canada, Contribution Series 20170171
PublisherSpringer Nature
Mediapaper; on-line; digital
File formatpdf
Subjectsremote sensing
ProgramGeodetic Survey, Canadian Spatial Reference System
Released2018 03 03
AbstractGLONASS ambiguity resolution in differential real-time kinematic (RTK) processing is affected by inter-frequency phase biases (IFPBs). Previous studies empirically determined that IFPBs are linearly dependent on the frequency channel number and calibration values have been derived to mitigate these biases for geodetic receivers. The corresponding IFPB-constrained model is currently the de facto approach in RTK, but the growing market of GNSS receivers, and especially low-cost receivers, makes calibration and proper handling of metadata a complex endeavor. Since IFPBs originate from timing offsets occurring between the carrier phase and the code measurements, we confirm other studies that show that IFPBs are not exactly linearly dependent on the frequency channel number, but rather linearly dependent on the channel wavelength, which calls for a modification in the GLONASS functional model. As an alternative to calibration, we revisit a calibration-free method for GLONASS ambiguity resolution and provide new insights into its applicability. A practical experiment illustrates that the calibration-free approach can offer better ambiguity fixing performance when the uncertainty on the IFPB parameter is large, unless partial ambiguity resolution is performed.
Summary(Plain Language Summary, not published)
NRCan provides GPS solutions that enable clients to obtain consistent cm-level positioning in the Canadian Spatial Reference System. Clients will benefit from the addition of GLONASS and Galileo constellations through increased reliability and improved accuracy. However, use of different satellite constellations and receiver types presents many signal processing challenges to ensure full consistency and realize the cumulative benefits of these systems. Signal phase biases are a notable concern for the GLONASS constellation and careful treatment is necessary. This investigation reports on a novel method to mitigate the impacts of such biases, resulting in simplified processing of data from mixed receiver types and firmware versions.