GPS + Galileo + QZSS + BDS tightly combined single-epoch single-frequency RTK positioning. Issue 376 (2nd January 2021)

• Record Type: Journal Article
• Authors: Zhu, Shaolin; Yue, Dongjie; Chen, Jian; Liu, Zhiqiang
• Is Part Of: Survey review. Volume 53:Issue 376(2021)
• Page Start: 16
• Page End: 26
• Publication Date: 2021-01-02
• Subjects: Multi-GNSS -- Differential inter-system bias -- Tightly combined double-difference model -- Single-epoch single-frequency RTK -- Integer ambiguity resolution; Surveying -- Periodicals; Great Britain -- Surveys -- Periodicals; 526.9
• DOI: 10.1080/00396265.2019.1681681
• Languages: English
• ISSNs: 0039-6265

Abstract

Abstract : The multi-GNSS fusion makes positioning more reliable and accurate. Considering the signal difference of different systems, GPS + Galileo + QZSS + BDS tightly combined double-difference model (TCDDM), including function and stochastic model, is proposed. The proposed model fully utilizes the overlapping frequency signals of various systems, and thus to enhance positioning model when DISBs are known beforehand. The observations of 3 ultra-short (1~10 m) and 3 short (4~10 km) baselines were processed by self-programming software, and the single-epoch single-frequency RTK performance using different system-combined models was evaluated by ambiguity-fixed correctness rate (ACR) and positioning accuracy. It demonstrated that three- and four-system TCDDM were superior to their corresponding loosely combined double-difference model (LCDDM) for ACR and positioning accuracy especially at high cut-off elevation. Moreover, four-system TCDDM had the best RTK performance obtaining average ACRs of 100% and 97.6% even at 25° cut-off elevation for ultra-short and short baseline, respectively.