Synergistic Interferometric GPS-INS

Daniel Tazartes, Robert Buchler, Howell Tipton, and Robert Grethel

Abstract:	lnterferometric GPS is a technique which employs measurements of carrier phase difference to provide highly accurate relative position measure- ments. The differencing inherent in the interfero- metric approach leads to cancellation of many errors including ionospheric and tropospheric errors, ephemeris errors, and selective availability. lntetferometric GPS using multiple antennae mounted on rigid baselines has been proposed for attitude determination. The advantages of this approach stem from the long term stability of GPS measurements and the relatively low projected cost of GPS receivers and antennae. However, GPS remains a low bandwidth sensor which is susceptible to shading and jamming. tively high performance inertial measurement unit. With this mechanization, attitude may be obtained at a high rate and with complete immunity to The conventional approach to obtaining high external jamming. bandwidth attitude information involves a rela- Unfortunately, high quality gyroscopes are required to provide accurate heading information and to maintain long term accuracy. While inertial measurement units with the necksary performance are readily available, their cost is prohibitive for many applications. A synergistic combination of interferometric GPS and low cost inertial provides the best of both worlds. lnterferometric GPS using only two antennae provides an accurate measure of heading. A low cost inertial measurement unit provides pitch and roll and aids in the acquisition of heading. The inertial system generates wide bandwidth data with the GPS providing long-term error bounding. Further, for short GPS outages, the inertial system acts as a “flywheel” thereby maintaining system performance in conditions of temporary jamming or shading. The combined system represents a low cost, highly robust approach to navigation and attitude determination.
Published in:	Proceedings of the 1995 National Technical Meeting of The Institute of Navigation January 18 - 20, 1995 Disneyland Hotel Anaheim, CA
Pages:	657 - 671
Cite this article:	Tazartes, Daniel, Buchler, Robert, Tipton, Howell, Grethel, Robert, "Synergistic Interferometric GPS-INS," Proceedings of the 1995 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 1995, pp. 657-671.
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