Two novel approaches to navigation using the Earth's gravity and magnetic fields

Presented in this dissertation are two navigation systems that exploit two of the earth's natural fields. The first exploits the earth's gravity field, while the other utilizes the earth's magnetic field. Part I presents an approach to gravity referenced navigation and Part II deals with a wing mounted strapdown magnetic azimuth detector.; Part I. Gravity referenced navigation. For many airborne missions precise navigation is necessary. Presently, aircraft must employ such aids as radar and Global Positioning System (GPS), to improve the overall navigation accuracy of the aircraft Inertial Navigation System (INS). Use of these types of aids could jeopardize the success of the mission because of their susceptibility to detection, jamming and countermeasures. Presented here is a gravity referenced navigation system that employs the use of Digital Terrain Elevation Daca (DTED) and a nearest neighbor neural network gravity gradient pattern matching to passively and covertly compensate for position error build up in the aircraft's INS. Presented is the system architecture, discussion of the network weight generation function, and a system simulation.; Part II. Magnetic azimuth detector for wing tip mount application. Magnetic Azimuth Detectors (MAD) currently deployed on military aircraft are unreliable and limited in their dynamic performance. The United States Air Force has issued a "Logistic Need" requesting alternate technological approaches to solve this problem. A strapdown magnetic azimuth detector could satisfy the Air Force need due to its inherent solid state nature (no moving parts). Addressed here are the instrument performance issues of a wing tip mounted solid state Magnetic Azimuth Detector (MAD). The approach taken here dynamically tracks the wing tip deflections so that when used in conjunction with a fuselage mounted Inertial Reference Unit (IRU), wing tip sensed magnetic measurements can be used to derive heading. Presented is a discussion of other strapdown approaches and their short comings with respect to wing mounted applications. This discussion is followed by a definition of the error sources associated with the new approach and a simulation illustrating the expected performance.