General Model for Airborne and Spaceborne Linear Array Sensors

This paper describes a general model for CCD linear array sensors with along-track stereo viewing. The sensor external orientation, which is different for each image line, is modelled with time-dependent piecewise polynomial functions and integrated in the standard photogrammetric triangulation, resulting in an indirect georeferencing model. The continuity of the functions and their first and second derivatives between adjacent segments is imposed. In case of sensors carried on airplane, the sensor position and attitude observed by GPS/INS instruments are included in the piecewise polynomial functions. Using Ground Control Points (GCPs) and, additionally, Tie Points (TPs), the function parameters and the ground coordinates of the TPs are estimated in a least-squares adjustment. The model was tested on imagery acquired by TLS and MOMS-02 sensors, which were carried on helicopter and satellite respectively, using different numbers and distributions of GCPs. The Japanese TLS (Three-Line Sensor) scans along-track in 3 directions with a one-lens optical system. The sensor external orientation for each image line was available by GPS/INS instruments, together with 46 GCPs measured in the images. An absolute accuracy of 4-13 cm in planimetry and 6-16 cm in height was achieved (ground pixel size: 10 cm). MOMS-02 sensor was carried on the Russian MIR station. The stereopairs used for the test were acquired during the Priroda mission in 1997 and had ground resolution of 18m. The preliminary results showed an absolute accuracy of 6.3-9.3 m in planimetry and 3.0-12.3 m in height.