LTC Wright & LTC Oxendine Present at IEEE IGARSS

LTC Wright and LTC Oxendine presented their paper “Classifying Terrestrial Based Forest Photography with Geographic Information Systems to Model Signal Loss” at the Institute of Electrical and Electronics Engineers (IEEE) International Geoscience and Remote Sensing Symposium in Valencia, Spain. Their paper addressed the challenges of using GPS receivers in forest environments, where GPS L-band signals are attenuated by vegetation. It is problematic to predict the quality of signal reception in forested areas. To predict GPS signal attenuation, they developed a quantitative measure of the local forest structure and density. Terrestrial based hemispherical sky-oriented photographs were used to rapidly and remotely sample the structure and density of forest canopy. This study determined the attenuation of GPS signals in forests, by correlating changes in the signal-to-noise ratio of the received GPS signals under different canopies, using the observed canopy closure at the directed location of individual GPS satellite vehicles derived from terrestrial photography. Their results verified that the loss of signal is strongly correlated with the local structure and density of the forest and demonstrate how the calculated canopy closure can be used to better predict the attenuation of the GPS signals. The results also pertain to satellite communications, cellular signals, and the estimation of biomass from L-band radar.