Performance characterization of GPS receivers under tree canopies

The availability of low-cost receivers has significantly broadened the use of the Global Positioning System (GPS). The GPS transmits a circularly polarized, L-band signal, which if line-of-sight (LOS) cannot be established is subject to significant polarization distortion and signal degradation. In this work, blockage by trees and their effect on path loss and polarization distortion of the GPS signal is analyzed.