Ground control for the geometric correction of PAN imagery from Indian remote sensing (IRS) satellites

Efficacy of a hand-held global positioning system (GPS) receiver in stand-alone mode of GPS measurements was investigated by taking measurements on different dates. These measurements were compared to those observed by DGPS and total station for the validation of hand-held GPS receiver accuracy. Ground control point (GCP) coordinates were derived from 1:25,000 and 1:50,000 scale topographic maps, and by using two different types of GPS receivers- a stand-alone hand-held and dual frequency DGPS receivers. GCPs derived from each source were used independently for the GCP-based geometric correction of IRS PAN sensor images by using affine mapping function. GCPs derived from maps yielded root mean squares (RMS) error from 15 to 35 m respectively. However, GCPs derived by DGPS or stand-alone mode hand-held GPS receiver gave RMS error in the range of 3 to 6 meter, which is very close to spatial resolution of PAN sensor imagery (5.8 m). The mean values of GCP coordinates observed with the help of hand-held GPS receiver in stand-alone mode might prove a cost effective solution for the determination of GCP coordinates in the geometric correction of current high-resolution imagery from IRS satellites.