IEEE Instrumentation & Measurement - September 2023 - 46

-6.2
-6.0
-5.8
-5.6
-5.4
-5.2
-5.0
-4.8
-4.6
GPS + BDS (STD = 0.0235) BDS (STD = 0.0296) - 0.2 ns
086
088
090
092
DoY (300 s interval)
Fig. 5. PPP-B2b zero-baseline CCD for 11 days from DoY 86 to 96 in 2022.
12
16
-16
-12
-8
-4
4
8
166
167
168
Fig. 6. BDS + GPS PPP-B2b time comparison residual.
12
16
-16
-12
-8
-4
4
8
166
167
168
Fig. 7. BDS PPP-B2b time comparison residual.
Table 3 - STD values of PPP-B2b time comparison
residual (ns)
Time link
NTSC-TLM2
NTSC-USUD
NTSC-CUSV
Model
GPS + BDS
0.4287
0.5028
0.5328
BDS
0.3995
0.5112
0.5425
station (CUSV) with an internal clock which were equipped
with BDS-3 and GPS receivers were selected to validate the
SF PPP-B2b time comparison from NTSC zero-baseline CCD
and long-baseline time links. The GBM product was used
46
169
DoY
169
DoY
094
096
PPP-B2b SF TLM2 (-10 ns)
PPP-B2b SF USUD
PPP-B2b SF CUSV (-91 ns)
170
171
172
PPP-B2b SF TLM2 (-20 ns)
PPP-B2b SF USUD
PPP-B2b SF CUSV (-90 ns)
as a reference to measure
the accuracy of the time
comparison using the PPPB2b
product. Compared
with GBM time comparison,
the reference time
contained in the receiver
clock offset using the PPPB2b
product is continuous.
The receiver clock offset
through GPS time transfer
using the PPP-B2b product
is intermittent. Only GPS
SF PPP-B2b time comparison
is not recommended,
which is similar to DF
PPP-B2b time transfer.
The CCD result sequence
of SF PPP-B2b fluctuates
within 0.2 ns. Taking the
GBM product as a reference,
the STD values of
SF PPP-B2b time comparison
using GRAPHIC SF
PPP-B2b model can be
0.5 ns. Meanwhile, the addition
of GPS system does
not significantly improve
the PPP-B2b time transfer
accuracy.
170
171
172
Acknowledgment
The authors acknowledge
TL, IGS and GFZ for providing
observations and precise
satellite orbit and clock
products. This research was
funded by the State Key
Laboratory of Geodesy and
Earth's Dynamics (Grant
No. SKLGED2022-3-3).
References
[1] J. Zumberge et al, " Precise point positioning for the efficient and
robust analysis of GPS data from large networks, " J. Geophysical
Research-Solid Earth, vol. 102, pp. 5005-5017, Mar. 1997.
[2] J. H. Zhang, S. W. Dong, H. B. Yuan, W. Guang, Y. Zhang et al,
" Study on PPP time comparison based on BeiDou-3 new signal, "
IEEE Instrum. Meas. Mag., vol. 25, pp. 30-40, Aug. 2022.
[3] Y. L. Ge, S. X. Chen, T. Wu, C. M. Fan, W. J. Qin, F. Zhou and X.
H. Yang, " An analysis of BDS-3 real-time PPP: time transfer,
positioning, and tropospheric delay retrieval, " Measurement, vol.
172, article 108871, Feb. 2021.
[4] " BeiDou Navigation Satellite System Signal in Space Interface
Control Document Precise Point Positioning Service Signal
PPP-B2b (Version 1.0), " China Satellite Navigation Office, Aug.
IEEE Instrumentation & Measurement Magazine
September 2023
Clock difference (ns)
Clock difference (ns)
Clock difference (ns)
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