Precise Orbit Determination of Global Navigation Satellite System of ...

Chapter 9 Software and Simulation Results
Figure 9-51 shows the accuracies of x, y, z coordinates of orbit determination for a IGSO satellite located at
λ=60° with float ambiguity solution considering the satellite visibility and observation sample rate 1 minute are
±0.12 m, ±0.12 m and ±0.05 m respectively. Figure 9-52 and Figure 9-53 show the related ambiguity solution.
The results above show that the accuracy of dynamic orbit determination has been significantly improved using
carrier phase observation with a sample rate of 1 min. The initial integer ambiguities have been quickly resolved.
This is because, using observations with a sample rate of 1 min, the satellite dynamic model errors and some
time-related errors are reduced. The disadvantage of observations with a sample rate of 1 minute is that the
amount of observation data will be too large to be processed for orbit determination. My suggestion is, after
integer or float ambiguities are resolved, the observations with a sample rate of 10 min can be used for following
orbit determination.
The following are the results of dynamic orbit determination using observations with a sample rate of 5 min.
Difference (meter)
10
8
6
4
2
0
-2
-4
-6
-8
-10
0 24 48 72 96 120 144 168 192 216 240
Tim e (hour)
Figure 9-49 Accuracy of Orbit Determination of an IGSO Satellite at λ=-10° with Float Ambiguity Solution and Sample Rate
5 min
Ambiguity
21
20.8
20.6
20.4
20.2
20
19.8
19.6
19.4
19.2
19
0 24 48 72 96 120 144 168 192 216 240
Tim e (hour)
Figure 9-50 Float Ambiguity Solution of an IGSO satellite at λ=-10° at Tracking Station 1
135
dx
dy
dz