NASA 1996 SBIR Phase I

PROJECT TITLE : Multipath-Resistant GPS Carrier Tracking

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Hittite Microwave Corporation proposes to develop an innovative approach to GPS carrier tracking,which uses multiple quadrature correlation measurements equispaced in carrier phase in order to minimize multipath- induced errors in carrier tracking. The nomelty of our technique, compared to previous multipath mitigation techniques is that it compensates for the multipath distortions in the phase detector without attempting to resolve the various multipath signals, therby avoiding the need for long integration times and numerically sensitive solutions of systems of nonlinear equations. Mitigation of the multipath distortion in carrier tracking is essential for accurate attitude estimation, specially in microspacecraft applications. The main goals of the proposed Phase I research are: (i) Assess the performance inprovement of the proposed carrier tracking compared to the classical arctan carrier tracking under multipath distortions, (ii) Develop an implementation approach for Phase II demonstration, and in particular determine the feasigility of an all-software implementation of the proposed technique.

High-performance GPS attitude systems for aviation and spacecraft applications. Robust coherent GPS tracking under poor signal-to-noise ratio (SNR) conditions.

George Dimos
Hittite Microwave Corporation
21 Cabot Road
Woburn, MA 01801

Hittite Microwave Corporation
21 Cabot Road
Woburn, MA 01801