Date of Award


Document Type


Degree Name

Master of Science


Department of Electrical and Computer Engineering

First Advisor

Meir Pachter, PhD


The theory for Inertial Navigation System (INS) aiding using passive, bearings only measurements of an unknown stationary ground object, in the vein of optical flow measurement, is developed. Stand-alone bearings-only measurements over time of an unknown, but stationary, ground object are shown to yield estimates of the aircraft’s aerodynamic angles, viz., the angle of attack and sideslip angle. Two new equations containing the aircraft’s angular navigation variables ψ, θ, φ, γ, H, and the aerodynamic angles are derived. This allows an update of the aircraft’s attitude, thus making INS aiding using passive, bearings-only measurements possible. Moreover, the use of stadiametry, knowledge of the ground object’s elevation, and an independent baro-altitude measurement yields an improved estimate of the aircraft’s positional variables, thus completing the INS aiding task. At the same time, the geo-location of the observed ground object is also obtained. In addition, prior information on the position of the ground object further enhances the positional navigation variables’ estimate, thus bringing to full fruition the favorable synergy of INS and bearings-only measurements of an unknown ground object.

AFIT Designator


DTIC Accession Number