Marine Communications Channel Modeling Using the Finite-Difference Time Domain Method

Broad area maritime surveillance (BAMS) is a current interest area for the application of unmanned aerial vehicles (UAVs). Robust communications is a primary concern that impedes the general acceptance of UAVs by the Federal Aviation Administration (FAA), as loss of communications link is generally perceived as a loss of vehicular control. Thus, to gain an increased understanding of the communications channel UAVs' experience during low-level maritime operations, a channel-modeling effort using the finite-difference time domain method (FDTD) is conducted. The focus of this effort has been to assess the effects of sea surface shadowing conditions on the marine communications channel. A 2-D electromagnetic (EM) simulator has been developed, utilizing modified Pierson-Moskowitz (PM) spectral models to generate a random sea surface in a deep-water location from which multipath scattering is produced. Data analysis conducted on the transient EM simulation results has produced generalized path loss exponent, standard deviation, mean excess delay, and root mean square delay models as a function of frequency and observable sea surface height for fixed transmitter and receiver locations.