INS AIDING USING BEARINGS-ONLY MEASUREMENTS OF KNOWN GROUND OBJECTS

The INS aiding action of passive bearings-only measurements of ground objects is investigated. This paper carefully derives the equations needed to synthesize an Extended Kalman Filter in order to incorporate these measurements online into an INS and achieve INS aiding action using optical, bearings-only measurements of ground objects. Most importantly, the observability of this measurement arrangement is analyzed with a view to assessing the INS aiding action. The goal of this paper is to elucidate and demonstrate the true aiding strength provided by passive bearings-only measurements of ground objects, as well as provide insight into, and analytical tools for the design of such systems. It is shown that optically tracking two known ground features suffices to guarantee observability, and consequently, full INS aiding.