Airborne high-resolution digital imaging system

Abstract

A low-cost airborne digital imaging system capable to perform aerial surveys with small-format cameras is introduced. The equipment is intended to obtain high-resolution multispectral digital photographs constituting so a viable alternative to conventional aerial photography and satellite imagery. Monitoring software handles all the procedures involved in image acquisition, including flight planning, real-time graphics for aircraft position updating in a mobile map, and supervises the main variables engaged in the imaging process. This software also creates files with the geographical position of the central point of every image, and the flight path followed by the aircraft during the entire survey. The cameras are mounted on a three-axis stabilized platform. A set of inertial sensors determines platform's deviations independently from the aircraft and an automatic control system keeps the cameras at a continuous nadir pointing and heading, with a precision better than ± 1 arc-degree in three-axis. The control system is also in charge of saving the platform’s orientation angles when the monitoring software triggers the camera. These external orientation parameters, together with a procedure for camera calibration give the essential elements for image orthocorrection. Orthomosaics are constructed using commercial GIS software. This system demonstrates the feasibility of large area coverage in a practical and economical way using smallformat cameras. Monitoring and automatization reduce the work while increasing the quality and the amount of useful images.