Servo requirements for FCC VMES compliance: Servo performance levels required to meet FCC VMES pointing requirements for satcom-on-the-move antennas on ground vehicles

The FCC recently issued final regulations on the operation of Ku-band mobile satellite communication antennas mounted to ground vehicles. The “Vehicle-Mounted Earth Station” (VMES) regulations set limits on the transmitted power density broadcast to an adjacent satellite by the mobile, satcom-on-the-move (SOTM) antenna. The challenge presented by these requirements varies depending on the configuration of the SOTM antenna as well other factors, such as satellite elevation and vehicle operating conditions, but in any case these challenges are not trivial. A brief overview of the requirements is provided. Several classes of antennas are defined, including pointing versus tracking antennas, and mechanically steered versus electronically steered. For each class of antenna, standardized servo performance metrics are defined and their relation to the VMES requirements derived and discussed.