Mobile Gravity Vector Surveying & Precise Attitude Determination from Integrated DGPS/INS & DGPS/INS/Gravity Gradiometer Data

David Gleason, Todd Kawakami, Roger Sands, James Battis and Anestis Romaides

Abstract:	It is well-known unaccounted systematic errors in high accuracy strapdown INS’s and limited resolutions in geodetic GPS receiver phase observables restrict the useful determination of the gravity vector on a mobile platform, usually assumed to be an aircraft. Furthermore, several tests by some organizations have shown eigenmotions of the aircraft further limit the resolution of the recoverable gravity vector signal. In an attmept to overcome such limitiations of a GPS/INS gravity recovery payload, the Air Force is supplementing a land vehicle’s multiple antenna GPS/INS nav system with the world’s only moving-base, full tensor, gravity gradiometer (GG). The GG will supply the nav system with omnidirectional external gravity gradient updates. The size of the gradiometer’s existing and outdated electronics system prevents it from being placed in an aircraft. Installing a state-of-the-art electronics support system would allow future airborne experiments, preferably with state-of-the- art gyroscopic and accelerometer sensors. This paper examines the theoretical and engineering challenges related to developing a mobile GPWINWGG gravity vector surveying system. In particular, the paper (1) shows the necessity of multiple-antenna GPS vehicle attitude updates, owing to the inseparable cross-couplings between the north-south leveling error and east-west horizontal or deflection of the vertical component of the vehicle-borne gravity vector and vice versa; (2) presents the Kalman error state models and five types of DGPS and GG external updates required to optimally estimate vehicle- borne gravity vectors from integrated DGPS/ IlWGG data streams; and (3) expounds on the results of simulations and error analyses that predict the suitability of demo GPMNS airborne tests over Ohio wherein the effects of the self-generated errors of the GPS and INS sensors are highlighted.
Published in:	Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996) June 19 - 21, 1996 Royal Sonesta Hotel Cambridge, MA
Pages:	637 - 645
Cite this article:	Gleason, David, Kawakami, Todd, Sands, Roger, Battis, James, Romaides, Anestis, "Mobile Gravity Vector Surveying & Precise Attitude Determination from Integrated DGPS/INS & DGPS/INS/Gravity Gradiometer Data," Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996), Cambridge, MA, June 1996, pp. 637-645.
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