TT&C Bi-cone antenna patterns on MUOS spacecraft

Lockheed Martin is currently building mobile user objective system (MUOS) satellites for the US NAVY serving its telecommunications future demands. During the transfer orbit stage of each satellite launch lifetime, a bi-cone antenna is used to serve Telemetry, Track and Command (TT&C) functionality for the spacecraft. The design of the TT&C antenna takes into consideration various aspects of power, gain, and polarization to ensure continuous and reliable operation in space. The antenna location on the spacecraft has to ensure clear field of view (FOV) and sustain compliance to requirements similar to those of the stand-alone antenna. This pressure motivates early prediction and mitigation to any non-compliance issue where there are still schedule and cost margins in the satellite manufacturing cycle that allow fixing problems, if any, without affecting the whole program timeline. In this article, a straightforward approach to predict the bi-cone TT&C antenna patterns in the presence of the surrounding structure will be presented. Some model approximations, made to simplify the task, will be discussed. A mock-up test is performed to verify the model approximations and results. A sample of predicted data, followed by measured data will be shown.