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Mapping from Space & GPS
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Performance Evaluation Of Rtk Gps Without Sa Effect
Table 4 Statistical Analysis of Baseline Length
| Baseline |
Static GPS (m) |
RTK GPS (m) |
Deviation (m) |
| B013-B032 |
154.606 |
154.674 |
0.067 |
| B032-B034 |
194.390 |
194.683 |
0.294 |
| B034-B035 |
207.985 |
208.076 |
0.091 |
| B035-BL01 |
280.206 |
279.609 |
-0.597 |
| BL01-C026 |
328.431 |
328.428 |
-0.003 |
| C026-C027 |
144.843 |
144.857 |
0.014 |
| C027-C031 |
189.289 |
189.307 |
0.018 |
| C027-B034 |
210.626 |
210.691 |
0.064 |
| Max |
|
0.294 |
| Min |
|
-0.597 |
| Mean |
|
-0.007 |
| RMS |
|
0.196 |
5.2 RTK GPS without SA
After SA was turned off, the static and RTK GPS re-occupied the experimental network. Through the similar baseline processing and network adjustment, the outcomes of static GPS are still contemplated as the reference standard to judge the performance of RTK GPS without SA effect. The statistical analysis of TM 2° coordinates is listed in Table 4 that the deviation is less than 1cm in east and north directions and below 3cm in height, so the reliability of RTK GPS without SA is meaningful. At that time, the comparison task of RTK GPS with and without SA carried out and the estimated result is displayed in Table 6 that the discrepancy is below 3cm in east and north directions and about 10cm in height. It is compassion that only three points could evolve in the comparison because of satellite constellation and station surroundings.
Table 5 Statistical Analysis of TM 2° Coordinates
| Point |
E (cm) |
N (cm) |
H (cm) |
| Max |
1.3 |
1.5 |
4.5 |
| Min |
-1.6 |
-2.2 |
-10.9 |
| Mean |
-0.13 |
0.04 |
-2.90 |
| RMS |
0.50 |
0.79 |
3.59 |
Table 6 Comparison of RTK GPS with and without SA
| Point |
DE (m) |
DN (m) |
DH (m) |
| B032 |
0.031 |
0.038 |
-0.125 |
| BL01 |
-0.012 |
0.062 |
-0.144 |
| C027 |
-0.027 |
0.047 |
-0.163 |
6. Conclusions
According to the preliminary analysis on horizontal vector, vertical vector and baseline length, the RTK GPS does denote to have the capability of static GPS technique in positioning. In other words, the RTK GPS technique is feasible, effective, and efficient for positioning and other applications, but the stableness is the most concern issue. Obviously, the reliability of RTK GPS could reach the centimeter level that is very near the order of static GPS, but the RTK GPS affected by SA on or off is also limited in centimeter level. The major difficulty of RTK GPS is the obstruction around station and the capability of radio power.
7. References
-
Abidin, H.A., 1994. On-the-Fly Ambiguity Resolution. GPS World, No. 4, pp. 47-56.
- Kaplan, E.D., 1996. Understanding GPS Principles and Applications. Artech House, New York.
- Langley, R.B., 1998. RTK GPS. GPS World, No. 9, pp. 70-76.
- Leick, A., 1996. GPS Satellite Surveying. John Wiley & Sons, Inc., New York. pp. 317-409.
- Teunissen, P.J.G., 1998. GPS for Geodesy. Springer-Verlag, New York, pp. 271-318.
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