Fast AT: A simple procedure for quasi direct orientation

Over the past two decades, the development of Global Navigation Satellite System (GNSS) technology, inertial navigation technology and Inertial Navigation Systems (INS) and their application to sensor orientation in photogrammetry and remote sensing has led to more precise, accurate, reliable and cost efficient orientation and calibration methods and procedures. Today, most airborne photogrammetric and remote sensing systems are equipped with GNSS receivers and inertial sensors. To a large extent and more or less independently from the imaging geometry and sensor type, orientation is performed with the direct and integrated methods. In this paper we introduce a new orientation method that we call Fast AT for frame images. The new method combines image measurements, ground control and aerial control observations in novel quantitative and qualitative ways. Depending on project specifications, Fast AT can be a robust alternative to direct orientation and, at the very least, a fast quality control tool for any orientation task. We analyze the performance of Fast AT with analogue and digital frame imagery and draw conclusions on its general properties. (C) 2012 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier B.V. All rights reserved.