Joint estimation of GPS/BDS real-time clocks and initial results

TitleJoint estimation of GPS/BDS real-time clocks and initial results
Publication TypeJournal Article
Year of Publication2016
AuthorsZhang W.X, Lou Y.D, Gu S.F, Shi C., Haase JS, Liu J.N
JournalGps Solutions
Date Published2016/10
Type of ArticleArticle
ISBN Number1080-5370
Accession NumberWOS:000384421600006
Keywordsbiases; Clock estimation; Inter-system bias; Multi system; navigation satellite system; ppp; precise orbit determination; Real time

We present the joint estimation model for Global Positioning System/BeiDou Navigation Satellite System (GPS/BDS) real-time clocks and present the initial satellite clock solutions determined from 106 stations of the international GNSS service multi-GNSS experiment and the BeiDou experimental tracking stations networks for 1 month in December, 2012. The model is shown to be efficient enough to have no practical computational limit for producing 1-Hz clock updates for real-time applications. The estimated clocks were assessed through the comparison with final clock products and the analysis of post-fit residuals. Using the estimated clocks and corresponding orbit products (GPS ultra-rapid-predicted and BDS final orbits), the root-mean-square (RMS) values of coordinate differences from ground truth values are around 1 and 2-3 cm for GPS-only and BDS-only daily mean static precise point positioning (PPP) solutions, respectively. Accuracy of GPS/BDS combined static PPP solutions falls in between that of GPS-only and BDS-only PPP results, with RMS values approximately 1-2 cm in all three components. For static sites, processed in the kinematic PPP mode, the daily RMS values are normally within 4 and 6 cm after convergence for GPS-only and BDS-only results, respectively. In contrast, the combined GPS/BDS kinematic PPP solutions show higher accuracy and shorter convergence time. Additionally, the BDS-only kinematic PPP solutions using clock products derived from the proposed joint estimation model were superior compared to those computed using the single-system estimation model.

Short TitleGPS Solut.
Student Publication: