1. A method for determining the height H T of a target above a surface, the method comprising the steps of: determining a distance R from a source to a target; determining a distance L representative of a distance traveled by a signal from the target that is reflected by the surface to the source; determining a height H of the source above the surface; and determining the height H T of the target using the equation: H T = ( L 2 - R 2 ) 4 ⁢ H .