Page 134 - 卫星导航2021年第1-2合期

Liu et al. Satell Navig (2021) 2:6 Satellite Navigation
https://doi.org/10.1186/s43020-021-00038-y
https://satellite-navigation.springeropen.com/

ORIGINAL ARTICLE Open Access

Single-epoch RTK performance assessment

of tightly combined BDS-2 and newly complete

BDS-3

2
1
1*
1
1
Wanke Liu , Mingkui Wu , Xiaohong Zhang , Wang Wang , Wei Ke and Zhiqin Zhu 1
Abstract
The BeiDou global navigation satellite system (BDS-3) constellation deployment has been completed on June 23,
2020, with a full constellation comprising 30 satellites. In this study, we present the performance assessment of single-
epoch Real-Time Kinematic (RTK) positioning with tightly combined BeiDou regional navigation satellite system
(BDS-2) and BDS-3. We frst investigate whether code and phase Diferential Inter-System Biases (DISBs) exist between
the legacy B1I/B3I signals of BDS-3/BDS-2. It is discovered that the DISBs are in fact about zero for the baselines with
the same or diferent receiver types at their endpoints. These results imply that BDS-3 and BDS-2 are fully interoper-
able and can be regarded as one constellation without additional DISBs when the legacy B1I/B3I signals are used
for precise relative positioning. Then we preliminarily evaluate the single-epoch short baseline RTK performance of
tightly combined BDS-2 and the newly completed BDS-3. The performance is evaluated through ambiguity resolu-
tion success rate, ambiguity dilution of precision, as well as positioning accuracy in kinematic and static modes using
the datasets collected in Wuhan. Experimental results demonstrate that the current BDS-3 only solutions can deliver
comparable ambiguity resolution performance and much better positioning accuracy with respect to BDS-2 only
solutions. Moreover, the RTK performance is much improved with tightly combined BDS-3/BDS-2, particularly in chal-
lenging or harsh conditions. The single-frequency single-epoch tightly combined BDS-3/BDS-2 solution could deliver
an ambiguity resolution success rate of 96.9% even with an elevation cut-of angle of 40°, indicating that the tightly
combined BDS-3/BDS-2 could achieve superior RTK positioning performance in the Asia–Pacifc region. Meanwhile,
the three-dimensional (East/North/Up) positioning accuracy of BDS-3 only solution (0.52 cm/0.39 cm/2.14 cm) in the
kinematic test is signifcantly better than that of the BDS-2 only solution (0.85 cm/1.02 cm/3.01 cm) due to the better
geometry of the current BDS-3 constellation. The tightly combined BDS-3/BDS-2 solution can provide the positioning
accuracy of 0.52 cm, 0.22 cm, and 1.80 cm, respectively.
Keywords: BeiDou global navigation satellite system, BDS-2, Real-time kinematic, Diferential inter-system bias,
Ambiguity resolution

Introduction global navigation satellite system (BDS-3) (Yang et al.
BeiDou Navigation Satellite System (BDS) was devel- 2019b). Te built-up of BDS-3 began with the launch of
oped into three phases, the BeiDou demonstration navi- fve experimental satellites from March 2015 to Febru-
gation satellite system (BDS-1), the BeiDou regional ary 2016, including three Medium Earth Orbit (MEO)
navigation satellite system (BDS-2), and the BeiDou and two Inclined Geostationary Orbit (IGSO) satellites,
which were designed to perform in-orbit verifcation of
the new payloads, new signals, and new techniques (Xie
*Correspondence: xhzhang@sgg.whu.edu.cn et al. 2018; Yang et al. 2018, 2019b). Te operational
1 School of Geodesy and Geomatics, Wuhan University, Wuhan 430079,
China BDS-3 was started in November 2017, and in the end of
Full list of author information is available at the end of the article 2018, the BDS-3 primary system consisting of 18 MEO

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