The Charles Stark Draper Laboratory, Inc.

Frank E Mullen

William L Robbins

Richard L Greenspan

Multipath propagation detection can be accomplished using first and second spaced antennas which receive a carrier signal from a moving radiation source and produce a carrier phase difference representative of the location of the source; a difference signal representative of the difference between the measured carrier phase difference and a predetermined phase difference for the source in that location is generated; and the presence of multipath distortion in that difference signal is determined. Furthermore, when a multiplicity of source signals are tracked as in reception of navigation signals from the Global Positioning Satellite System, the receiver may be programmed to eliminate or suppress errors arising from measurements that have been distorted by multipath propagation.

Multipath propagation detection and avoidance method and system

The present invention provides an antenna including a relatively thin substantially planar electrically conductive first layer substantially lying in a first plane, and a relatively thin substantially planar electrically conductive second layer substantially lying in a second plane. The first and second layers are disposed such that the first and second planes are substantially parallel and such that they are separated by a distance d. The second layer is smaller than and overlies the first layer and defines a first region extending between the second layer and a portion of the first layer underlying the second layer. The antenna further includes a first dielectric medium having a relatively high dielectric constant and disposed in the first region, and a second dielectric medium having a relatively low dielectric constant and disposed in a second region extending between the first layer and portions of the second plane overlying the first layer and excluding the first region.

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North Easton, MA, United States of America

Frank E Mullen