Alan S. Willsky. / "December, 1981." / "National Science Foundation ... Grant ECS-8012668"

Vertical line arrays (VLAs) deployed below the critical depth in the deep ocean can exploit reliable acoustic path (RAP) propagation, which provides low transmission loss (TL) for targets at moderate ranges, and increased TL for distant interferers. However, sound from nearby surface interferers also undergoes RAP propagation, and without horizontal aperture, a VLA cannot separate these interferers from submerged targets. A recent publication by McCargar and Zurk (2013) addressed this issue, presenting a transform-based method for passive, depth-based separation of signals received on deep VLAs based on the depth-dependent modulation caused by the interference between the direct and surface-reflected acoustic arrivals. This thesis expands on that work by quantifying the transform-based depth estimation method performance in terms of the resolution and ambiguity in the depth estimate. Then, the depth discrimination performance is quantified in terms of the number of VLA elements.

The use of communication satellites operating above 10 GHz has prompted research on the attenuating effects of rain on these signals. Frequency scaling, a technique where attenuation at one frequency can be scaled up (or down) to another frequency, can extend the known data base of propagation impairments. This thesis studies the ratios of attenuations in frequency pairs 14/11, 30/20, 30/11, and 20/14 GHz. The attenuation data were derived from a year-long propagation experiment which used a dual-polarized radar to estimate drop size distributions on a slant path between Blacksburg, Virginia, and the Intelsat VA F10 satellite. The effect of varying drop size distributions on attenuation ratios is discussed. An uplink power control simulation is developed using the attenuation ratios. Attenuation on the uplink path is estimated by scaling the measured downlink attenuation by the appropriate attenuation ratio. The evidence suggests that an uplink power control scheme using drop size distribution-based attenuation ratios offers improvement in satellite link reliability during rain storms. / Master of Science