Bernese GPS Software Version 5.0 - Bernese GNSS Software

∆δ(PTBB)
20 ps
15 ps
10 ps
5 ps
0 ps
0 4 8 12 16 20 24
Hours of doy 2003-139
∆δ(PTBB)
20 ps
15 ps
10 ps
5 ps
0 ps
14.2 Precise Clock Estimation
0 4 8 12 16 20 24
Hours of doy 2003-139
Figure 14.4: Comparison of the precise receiver clock synchronization with the clock estimation
from the corresponding network solution for the station PTBB,
session 1390 in year 2003 from the example in Section 20.4.4.
In the left figure the coordinates and troposphere parameters are identical
for the receiver clock synchronization and the network solution whereas in
the right hand figure those parameters are recomputed independently for the
receiver clock synchronization.
14.2.4 Precise Receiver Clock Synchronization
If you have a consistent set of satellite orbits, Earth orientation parameters, and satellite
clocks, e.g., as a result from a clock estimation following the processing example in Section
20.4.4, you can synchronize more station clocks to this set of clocks. This works in
the same way as the precise point positioning described in the processing example (see
Section 20.4.1).
Figure 14.4 demonstrates the consistency between the clock results for the station PTBB
for session 1390 in year 2003 from a network solution (result from the example campaign in
Section 20.4.4, file ${P}/DOCU CLK/OUT/TT 03139.CLK) and a precise receiver clock synchronization.
All input options are taken from the last GPSEST run in the clock determination
example. The only difference is that the resulting satellite clock corrections
${P}/DOCU CLK/ORB/TT 03139.CLK are introduced as fixed when performing the receiver
clock synchronization for station PTBB (of course, only the observation files for PTBB
are used instead of the entire network). Coordinates and troposphere parameters are introduced
as known from a network solution (left) or recomputed together with the receiver
clock corrections (right).
The left hand diagram shows that the differences to the network solution are below
one picosecond if the station coordinates and the troposphere parameters are fixed
on the network results. In general, however, the station coordinates and the site troposphere
parameters need to be estimated as in the usual PPP approach. The results
of this PPP and the coordinate results from the corresponding network solution
(file ${P}/DOCU CLK/STA/ED 03139.CRD) differ by (−3.1, −0.4, +0.5) mm in the up, north,
and east components. This corresponds to an offset in the estimated receiver clock of about
10 ps which is reflected by the right hand diagram in Figure 14.4. An extended study about
error propagation for time transfer using the GPS can be found in [Dach et al., 2003].
This procedure allows you to estimate precise receiver clocks, but it is not possible to
include the results into the Bernese observation file. Therefore, this precise receiver clock
synchronization cannot replace the synchronization based on the program CODSPP in the
preprocessing step (see Section 6.3).
Bernese GPS Software Version 5.0 Page 297