Multipath Modeling and Test Results for JPALS Ground Station Receivers

J.P. Weiss, S. Anderson, P. Axelrad, R.L. Brinkley, R.P. Pennline

Abstract:	Multipath modeling includes simulation of different types of reflectors at a variety of distances from the Joint Precision Approach and Landing System (JPALS) Military Ground Segment (MGS). Receiver tracking algorithms are modeled to determine the response of the tracking loop to the reflected signal. We have completed work on models using idealized reflectors and are currently developing a more realistic advanced multipath model. This model allows an antenna environment to be modeled including multiple reflections, antenna pattern effects, and receiver tracking models. Multipath modeling will help determine the significance of multipath to the overall JPALS error budget. The purpose of the multipath lab testing is to characterize the multipath response of each candidate receiver in a controlled environment. In all, eight multipath scenarios are applied to each receiver under test (RUT). These range from single and double short/long delay multipath signals due to ideal reflectors to more complex, time varying multipath scenarios. A baseline fixed reception pattern antenna (FRPA) simulation was initially performed. One candidate receiver, a beam-steering system, has also been tested. Multipath analysis shows that the beam-steering has significant multipath reduction capabilities especially for scenarios with large amplitude multipath. Outdoor multipath testing of the candidate receiver systems is being performed at Wright-Patterson Air Force Base (WPAFB) at five sites. These locations span the range of multipath interference expected from an ideal setup to a more constrained MGS deployment. Initial results show P(Y) code multipath of up to 6m at sites with nearby metal reflectors.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	1801 - 1811
Cite this article:	Weiss, J.P., Anderson, S., Axelrad, P., Brinkley, R.L., Pennline, R.P., "Multipath Modeling and Test Results for JPALS Ground Station Receivers," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 1801-1811.
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