Atmospheric Models for Over-Ocean Propagation Loss
MIT Lincoln Laboratory Lexington United States
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Air-to-surface radio links differ from typical satellite communications links in that the path elevation angles are lower, often 2 5 degrees, and so have a longer extent through the atmosphere. When signal frequencies exceed 10 GHz, propagation loss due to absorption by atmospheric gases become a significant link budget term. Losses over the ocean are even higher than over-land losses, due to increased humidity. Finally, when high reliability is desired, the log-normal assumption used to estimate required power margins from the loss mean and standard deviation is not accurate. A set of atmospheric loss models has been developed from radiosonde profiles collected along the Atlantic coast of the United States, in order to accurately estimate high-reliability SHFEHF air-to-surfaceradio link performance in a maritime environment, Data was collected at three locations approximately spanning the East Coast of CONUS Chatham MA, Wallops Island VA, and Key West, FL. Weather station locations and identifiers are listed in Table 1. The large quantity of historical radiosonde data available for those locations was used to identify radiosonde profiles that occur with specified probabilities. Those profiles were used to predict required link performance to achieve high reliability at different locations and times of year.
- Radio Communications
- Atmospheric Physics