Commercial Cameras Accurate Focal Length Estimation for Satellite Optical Observation

Spacecraft orbit estimation based on optical observations captured by a commercial camera is considered to be a challenge. Camera focal length turned out to be a parameter of utmost importance. The main goal of this work is to develop different algorithms able to estimate the focal length of a commercial camera based on actual measurements (observations). Thirteen different algorithms, including different Kalman Filters, Genetic Algorithms, and Simulated Annealing, and three different cameras are used in this study. The results of these algorithms are compared in order to measure their efficiency and determine the best way to compute the focal length. It is found that the best performance (in terms of the selected cost function) is achieved by genetic algorithms. Estimation algorithms such as Kalman filters are useful when there is a large ambiguity associated with the value of camera focal length. The graphical solution is characterized by simplicity and relatively good performance.