A powerful and robust algorithm for the Indirect Method, i.e., the transformation of a 3D object point onto a 2D image point for linear pushbroom imagery: is proposed. This algorithm solves the transformation iteratively with an initial estimate of the 2D image point coordinates. However, this algorithm does not require any sophisticated procedures to determine a "good" initial estimate and it always converges to the correct solution. This algorithm works using the following procedures: first, with an (random) initial estimate of the 2D image point coordinates, calculate the attitude of the camera platform; second, with the given attitude, calculate the position of the camera platform and the 2D image point; and third, update the estimate with the calculated to image point coordinates and then go back to the first procedure and continue iteration until the estimated and calculated image point coordinates converge. Results of the experiment show that this algorithm converges very fast even when the initial estimate has a huge error.
