Article
Performance Evaluation of Real-Time Precise Point
Positioning with Both BDS-3 and BDS-2 Observations
Lin Pan
1,2,3
, Xuanping Li
1
, Wenkun Yu
1,
* , Wujiao Dai
1
, Cuilin Kuang
1
, Jun Chen
4
,
Fade Chen
4
and Pengfei Xia
5
1
School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
linpan@csu.edu.cn (L.P.); xpli1997@csu.edu.cn (X.L.); wjdai@csu.edu.cn (W.D.);
kuangcuilin@csu.edu.cn (C.K.)
2
Guangxi Key Laboratory of Spatial Information and Geomatics, Guilin 541004, China
3
Hunan Institute of Surveying and Mapping Technology, Changsha 410007, China
4
School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China;
cj_snake@whu.edu.cn (J.C.); fadechen@whu.edu.cn (F.C.)
5
GNSS Research Center, Wuhan University, 129 Luoyu Road, Wuhan 430079, China; pfxia130@whu.edu.cn
* Correspondence: geowkyu@csu.edu.cn
Received: 29 September 2020; Accepted: 21 October 2020; Published: 23 October 2020
Abstract:
For time-critical precise applications, one popular technology is the real-time precise point
positioning (PPP). In recent years, there has been a rapid development in the BeiDou Navigation
Satellite System (BDS), and the constellation of global BDS (BDS-3) has been fully deployed. In addition
to the regional BDS (BDS-2) constellation, the real-time stream CLK93 has started to support the
BDS-3 constellation, indicating that the real-time PPP processing involving BDS-3 observations
is feasible. In this study, the global positioning performance of real-time PPP with BDS-3/BDS-2
observations is initially evaluated using the datasets from 147 stations. In the east, north and upward
directions, positioning accuracy of 1.8, 1.2 and 2.5 cm in the static mode, and of 6.7, 5.1 and 10.4 cm
in the kinematic mode can be achieved for the BDS-3/BDS-2 real-time PPP, respectively, while the
corresponding convergence time with a threshold of 10 cm is 32.9, 23.7 and 32.8 min, and 66.9, 42.9
and 69.1 min in the two modes in the three directions, respectively. To complete this, the availability
of BDS-3/BDS-2 constellations, the quality of BDS-3/BDS-2 real-time precise satellite products, and the
BDS-3/BDS-2 post-processed PPP solutions are also analyzed. For comparison, the results for the GPS
are also presented.
Keywords: BDS-3; BDS-2; real-time; precise point positioning
1. Introduction
With a view to the need for social and economic development as well as national security, China
independently constructs and operates the BeiDou Navigation Satellite System (BDS), which is one
of the Global Navigation Satellite Systems (GNSSs). BDS is an important national temporal–spatial
infrastructure that is committed to providing all-weather and all-time positioning, navigation and
timing (PNT) service with high accuracies for users all over the world. For the development and
construction of BDS, great importance is attached by China. China has been exploring a path to
develop a navigation satellite system suitable for its national conditions since the 1980s. A development
strategy characterized by three steps was gradually formulated. The BeiDou navigation demonstration
system (BDS-1) was built in the first step. In 1994, China started BDS-1 construction. In 2000, China
launched two satellites in geostationary orbit (GEO), and then put BDS-1 into use. For the users in
China, BDS-1 could provide timing, positioning, a wide-area differential as well as short-message
Sensors 2020, 20, 6027; doi:10.3390/s20216027 www.mdpi.com/journal/sensors
