Combined GPS and BDS for single-frequency continuous RTK positioning through real-time estimation of differential inter-system biases

Gao, Wang; Meng, Xiaolin; Gao, Chengfa; Pan, Shuguo; Wang, Denghui

Abstract

Double-differenced (DD) ambiguities between overlapping frequencies from different GNSS constellations can be fixed to integers if the associated differential inter-system biases (DISBs) are well known. In this case, only one common pivot satellite is sufficient for inter-system ambiguity resolution. This will be beneficial to ambiguity resolution (AR) and real-time kinematic (RTK) positioning especially when only a few satellites are observed. However, for GPS and current operational BDS-2, there are no overlapping frequencies. Due to the influence of different frequencies, the inter-system DD ambiguities still cannot be fixed to integers even if the DISBs are precisely known. In this contribution, we present an inter-system differencing model for combined GPS and BDS single-frequency RTK positioning through real-time estimation of DISBs. The stability of GPS L1 and BDS B1 DISBs is analyzed with different receiver types. Along with parameterization and using the short-term stability of DISBs, the DD ambiguities between GPS and BDS pivot satellites and the between-receiver single-difference ambiguity of the GPS pivot satellite can be estimable jointly with the differential phase DISB term from epoch to epoch. Then the inter-system differencing model can benefit from the near time-constant DISB parameters and thus has better multi-epoch positioning performance than the classical intra-system differencing model. The combined GPS and BDS single-frequency RTK positioning performance is evaluated with various simulated satellite visibilities. It will be shown that compared with the classical intra-system differencing model, the proposed model can effectively improve the positioning accuracy and reliability, especially for severely obstructed situations with only a few satellites observed.

Citation

Gao, W., Meng, X., Gao, C., Pan, S., & Wang, D. (2018). Combined GPS and BDS for single-frequency continuous RTK positioning through real-time estimation of differential inter-system biases. GPS Solutions, 22(1), https://doi.org/10.1007/s10291-017-0687-5

• Journal Article Type: Article
• Acceptance Date: Nov 16, 2017
• Online Publication Date: Nov 21, 2017
• Publication Date: 2018-01
• Deposit Date: Jan 26, 2019
• Journal: GPS Solutions
• Print ISSN: 1080-5370
• Electronic ISSN: 1521-1886
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 22
• Issue: 1
• DOI: https://doi.org/10.1007/s10291-017-0687-5
• Public URL: https://nottingham-repository.worktribe.com/output/1498376
• Publisher URL: https://link.springer.com/article/10.1007%2Fs10291-017-0687-5
• Additional Information: This is a post-peer-review, pre-copyedit version of an article published in GPS Solutions. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10291-017-0687-5