What is SOTM?
Satcom On The Move (SOTM) describes satellite communication systems capable of maintaining a continuous satellite link while the user platform — a military vehicle, armoured personnel carrier, command vehicle, maritime vessel, train, or emergency response vehicle — is in motion. This distinguishes SOTM from SOTP (Satcom On The Pause), which only requires connectivity when the vehicle is stationary.
Technology options
Mechanically steered antennas: A motorised gimbal continuously adjusts the dish angle to track the satellite as the vehicle pitches, rolls, and yaws. Gyroscopic stabilisation maintains pointing accuracy during vehicle acceleration and terrain-induced vibrations. This approach provides high gain but adds mechanical complexity, failure modes, and vehicle height (an issue for military vehicles under low bridges). Electronically steered arrays (ESA/phased arrays): No moving parts; the beam is steered electronically in milliseconds. Modern SOTM flat-panel systems use phased arrays to track LEO satellites and GEO satellites seamlessly. Starlink's standard flat terminal is not officially rated for continuous SOTM but has been extensively used on vehicles in operational contexts.
Military applications
SOTM is a critical military communications capability, enabling command vehicles, forward artillery units, and logistics convoys to maintain secure high-bandwidth communications while manoeuvring. Defence SOTM terminals operate in X-band, Ka-band, and Ku-band. Major suppliers include L3Harris, Collins Aerospace, Thales, and Elbit Systems. The Ukraine conflict demonstrated the operational value of mobile SOTM capability extensively, with both Starlink terminals and dedicated SOTM systems deployed across all military vehicle classes.