BEARINGS-ONLY MEASUREMENTS FOR INS AIDING: THEORY FOR THE THREE-DIMENSIONAL CASE ⁄

The theory behind Inertial Navigation System (INS) aiding using passive, bearings-only measurements of an unknown landmark is developed. Previous research showed that passive, bearings-only measurements provide an eective means to aid an INS, but only the two-dimensional case was considered. This paper addresses the complexities of moving from two-dimensional to three-dimensional space. Passive, bearings-only measurements of an unknown ground object are shown to yield estimates of the aircraft’s angle of attack and sideslip angle, which in turn are used to aid the INS. The algorithm that forms the basis for INS aiding in three-dimensional space using passive, bearings-only measurements of an unknown ground object is derived.