System and method for determining a position of a target in an unbiased 3D measurement space: generating 2D measurement data in focal planes of each sensor; calculating a line of sight (LOS) from the target for each sensor; intersecting the LOSs and finding the closest intersection point in a 3D space; calculating a boresight LOS in 3D for each sensor; intersecting the boresight lines of sights for each sensor, and finding the closest intersection point in the 3D space to define an origin for forming the unbiased 3D measurement space; and forming local unbiased 3D estimates of the position of the target in the unbiased 3D measurement space as a difference between a closest point of the target LOS and a closest point of the boresight LOS.