Patent ID: 7359038

Claim:
A method of identifying the location of a ground target from an observation point that is at an elevation above a first reference point, the first reference point having an elevation above sea level and latitude and longitude coordinates, the method comprising the steps of: a) determining the observation point's elevation above the first reference point; b) determining the line-of-sight elevation angle from the observation point to the ground target; c) determining an azimuth angle to the ground target; d) calculating the latitude and longitude coordinates of the ground target using the latitude and longitude coordinates of the first reference point, the observation point elevation above ground, the line-of-sight elevation angle to the ground target and the azimuth angle to the ground target; e) reading from a data base, the earth's surface elevation above sea level at the ground target location determined from step d); f) determining the difference between the earth's surface elevation above sea level at the ground target location estimate determined from step d) and the earth's surface elevation above sea level at the first reference point determined in step a); g) if the result of step f) is zero or substantially equal to zero, determine the ground target location to be at an elevation above sea level determined in step e) and to have the longitude and latitude determined in step d); h) if the result of step f) is non-zero, determine a second reference point elevation from the difference obtained in step f) and then; i) assign the second reference point elevation determined in step h) to be the first reference point elevation to be used in a recalculation of step d); then ii) iteratively calculate steps d) to h) until the difference obtained in step f) is zero or substantially equal to zero.