1. 1 GPS processing. Sat07_82.ppt, 2007-10-23. 1.Directly from the observations 2.From differences (especially if vectors between points are to be determined) (1)Is flexible, no requirements about same satellites or sam epoch (2)Can only be used for shorter distances

2. 2 GPS Integer-ambguities, Sat07_82.ppt, 2007-10-23. One more frequency will help (is comming) Methods: Geometric Combination of measurements Search in integer space Combined (1) N fixed at beginning, and is kept fixed. Waves are counted. 1.-differences used to eliminate N (2) Regarded as integer: 2521.08 -> 2521.00 Closest integer used

3. 3 Search in integer space. Sat07_82.ppt, 2007-10-23..Software will tell how much better chosen solution is compared to next-best.

4. 4 Cycle-slips. Sat07_82.ppt, 2007-10-23. Due to: Obstructions Large ionospheric activity Multipath Low height angle Interference Sloping antenna Errors in processing

5. 5 Cycle-slips. Sat07_82.ppt, 2007-10-23. If station coordinates and orbits well known then one may follow how double differences change.

6. 6 GPS Accuracy, DOP. Sat07_82.ppt, 2007-10-23. Accuracy depends on instrument range error, σ r And on geometric configuration of satellites. Expressed using ”dillution of precision”, DOP...

7. 7 DOP. Sat07_82.ppt, 2007-10-23...

8. 8 DOP computation. Sat07_82.ppt, 2007-10-23..

9. 9 H and V DOP. Sat07_82.ppt, 2007-10-23. Rotation of coordinate system needed: Local East, North, Up.

10. 10 GPS processing. Sat07_82.ppt, 2007-10-23. Observations: Pseudo-ranges from P-code obs. Pseudo-range differences from Doppler shift Carrier-wave phases or phase-differences Travel-time differences from interferometric measurements

11. 11 GPS processing. Sat07_82.ppt, 2007-10-23. Observations: Pseudo-ranges from P-code obs. Pseudo-range differences from Doppler shift Carrier-wave phases or phase-differences Travel-time differences from interferometric measurements

12. 12 GPS processing. Sat07_82.ppt, 2007-10-23. Observations: Pseudo-ranges from P-code obs. Pseudo-range differences from Doppler shift Carrier-wave phases or phase-differences Travel-time differences from interferometric measurements