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GPS for geometric correction of remotely sensed imagery: possibilities after termination of SA
Conclusion
After termination of SA of GPS siganls, the hand-held GPS accuracy has improved considerably. Geometric correction of one sub-scene of PAN imagery, using GCPs derived by hand-held GPS receiver in stand alone mode, has yielded sub-pixel level geometric correction accuracy. In absence of precise GCP coordinates, a hand-held GPS can prove a cost effective solution for the geometric correction of satellite imagery and other applications.
Table 5 Hand-held GPS observations at stations no.1
| Date |
Time (IST) |
Latitude |
Longitude H (m) |
Eastings (m) |
Northings (m) |
| 09/5/02 |
19.45 Hrs. |
26°30'37.542 |
80°14'07.410" 72 |
423811.00 |
2932438.00 |
| 23/5/02 |
09:20 Hrs. |
26°30'37.542 |
80°14'07.290" 80 |
423808.63 |
2932439.68 |
| 24/5/02 |
09:00 Hrs. |
26°30'37.518 |
80°14'07.305" 69 |
423809.13 |
2932438.75 |
| 25/5/02 |
10:05 Hrs. |
26°30'37.419 |
80°14'07.410" 70 |
423809.61 |
2932436.53 |
| 28/5/02 |
10:40 Hrs. |
26°30'37.590 |
80°14'07.320" 71 |
423809.64 |
2932441.70 |
| 29/5/02 |
17:40 Hrs. |
26°30'37.734 |
80°14'07.224" 85 |
423805.51 |
2932445.42 |
| 30/5/02 |
17:30 Hrs. |
26°30'37.656 |
80°14'07.128" 68 |
423804.17 |
2932443.39 |
| 06/6/02 |
17:30 Hrs. |
26°30'37.674 |
80°14'07.698" 77 |
423809.50 |
2932445.58 |
| 10/6/02 |
18:05 Hrs. |
26°30'37.740 |
80°14'07.374" 74 |
423811.16 |
2932445.39 |
Table 6 Mean values of coordinates observed by single and dual frequency GPS receivers at station no.8.
| Observation details |
Latitude |
Longitude H (m) |
Eastings (m) |
Northings (m) |
| SR530 coordinates |
26°30'46.396 |
80°13'54.331" 100.01 |
423451.73 |
2932714.04 |
| GS5 coordinates |
26°30'46.200 |
80°13'54.231" 84.22 |
423448.81 |
2932707.97 |
Limitations
Investigations of this research paper are limited for the plannimetric accuracy only, and height information is not analyzed. GS5 receiver accuracy was tested for small area, however investigations are in progress for the testing of its accuracy on precisely established stations in Kanpur, Lucknow and Bhopal cities, using DGPS receivers.
Acknowledgement
This activity is funded by ISRO-IITK cell, I. I. T. Kanpur. The authors wish to thank Shri N. K. Agarwal, retd. Director Survey Training Institute, Hyderabad for useful discussions and suggestions and PG students of Geoinformatics Division, Civil Engg. Deptt., I. I. T. Kanpur for their help in field work.
Disclaimer
The trade and product names are mentioned only for completeness of this paper, and no endorsement is intended by the authors or the institution concerned.
References
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