Exact closed-form geolocation algorithm for Earth survey sensors

Abstract

A closed-form solution for geolocation of satellite-based Earth sensor data has been developed. The algorithms are exact, depending only upon the assumption of an ellipsoidal Earth model, and rely on vector and matrix algebra to improve computational efficiency. The values computed are the geodetic coordinates of observed locations (latitude and longitude) and the sensor and solar angles required by radiative transfer models (sensor and solar zenith and azimuth angles). An improvement in computation speed of a factor of two is achieved over a spherical trigonometry solution, along with a much greater accuracy on an ellipsoidal Earth. As much as a factor of six increase in speed is obtained over the more accurate iterative solution for just geodetic latitude and longitude.