On the interoperability of IGS products for precise point positioning with ambiguity resolution

Abstract

Techniques enabling precise point positioning with ambiguity resolution (PPP-AR) were developed over a decade ago. Several analysis centers of the International GNSS Service (IGS) have implemented such strategies into their software packages and are generating (experimental) PPP-AR products including satellite clock and bias corrections. While the IGS combines individual orbit and clock products as standard to provide a more reliable solution, interoperability of these new PPP-AR products must be confirmed before they can be combined. As a first step, all products are transformed into a common observable-specific representation of biases. It is then confirmed that consistency is only ensured by considering both clock and bias products simultaneously. As a consequence, the satellite clock combination process currently used by the IGS must be revisited to consider not only clocks but also biases. A combination of PPP-AR products from six analysis centers over a one-week period is successfully achieved, showing that alignment of phase clocks can be achieved with millimeter precision thanks to the integer properties of the clocks. In the positioning domain, PPP-AR solutions for all products show improved longitude estimates of daily static positions by nearly 60% over float solutions. The combined products generally provide equivalent or better results than individual analysis center contributions, for both static and kinematic solutions.

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Data availability

Several satellite orbit, clock and bias products used in this study are experimental and, therefore, not publicly available. The CNES/CLS products were retrieved from ftp://cddis.gsfc.nasa.gov, while the Wuhan University phase clock/bias products can be found at ftp://igs.gnsswhu.cn/pub/whu/phasebias. CODE products enabling PPP-AR are available for the rapid, final and MGEX analysis lines at the IGS data centers and from ftp://aiub.unibe.ch/CODE.

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Acknowledgements

This research was conducted under the initiative of the IGS PPP-AR working group. Thanks to Paul Collins of NRCan for providing feedback on the initial version of this paper, and to three anonymous reviewers for their comments and suggestions. This manuscript is published as Natural Resources Canada contribution number 20190080.

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Contributions

S.B. proposed the concept, processed the data and wrote the manuscript. J.G., S.L., S. Schaer, T.S. and S. Strasser contributed satellite orbit, clock and bias products, provided advice and reviewed the paper.

Corresponding author

Correspondence to Simon Banville.

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Banville, S., Geng, J., Loyer, S. et al. On the interoperability of IGS products for precise point positioning with ambiguity resolution. J Geod 94, 10 (2020). https://doi.org/10.1007/s00190-019-01335-w

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Keywords

  • GNSS
  • IGS
  • Precise point positioning (PPP)
  • Ambiguity resolution
  • Satellite clock combination
  • Observable-specific biases