Experimental Tests on the Benefits of a More Rigorous Model in Imu/gps System Calibration

System calibration is required in integrated IMU/GPS systems to account for the spatial offset and misalignment between IMU, GPS and camera frames; synchronization is to be maintained, to predict IMU/GPS position and orientation data at the mid-exposure time of the images. To this aim, measurement on the ground, complemented by a calibration flight over a test field, are performed. Depending on the mathematical model, a two steps or a single step procedure may be used to recover the calibration parameters. In the former, parameters are computed as a weighted average of the discrepancies between the exterior orientation (EO) parameters of the images derived from block adjustment and those computed from the IMU/GPS data, in the latter parameters are explicitly inserted in the collinearity equations and the IMU/GPS data are considered as pseudo-observed quantities, replacing EO parameters as unknowns in the block adjustment. Results of their application to a calibration test field over the town of Pavia are discussed.