Satellite communications for tactical UAVs: Gilat shows Viper Ka at Eurosatory 2026

Satellite communications for drones were a topic at Eurosatory 2026 in Paris, where the Viper Ka was on show: an electronically steered antenna (ESA) from Gilat subsidiary Raysat. Points in the system's favour include its scalability and several detailed technical solutions.

Gilad Landsberg, President of Gilat Defense, explained in an interview what sets the Viper Ka, developed by Raysat in Bulgaria, apart. It is a flat, fully digital satellite antenna designed specifically for tactical unmanned aerial vehicles (UAV). Measuring 40 × 20 × 7 centimetres, the unit weighs less than four kilograms without an integrated modem. Thanks to its low height of seven centimetres, it can be installed directly in aerodynamic drone fuselages.

It covers the entire Ka band: 27.5 to 31.0 gigahertz in the uplink and 17.7 to 21.2 gigahertz in the downlink. Military frequency bands can be enabled or disabled via software.

The Viper Ka has no moving parts. Instead of pointing the antenna mechanically at the satellite, the beam is steered purely electronically. To do this, the system drives numerous small antenna elements in the flat support structure with targeted phase shifts, allowing the beam to be steered in almost any direction. This is intended to improve reliability under vibration and in continuous operation.

Multiple orbits against high latency

A key topic that Landsberg highlighted at the exhibition is the latency of conventional geostationary (GEO) satellites, i.e. the delay of the signal on its way from transmitter to receiver.

For many tactical purposes such as drone control, real-time video or time-critical targeting, this is too much. Constellations in low Earth orbit (LEO) have minimal latency and are therefore much better suited to applications where real time matters. The Viper Ka can use GEO, MEO and LEO networks simultaneously and automatically selects the constellation that best fits the respective mission profile.

Satellite communications with limited on-board power

Energy demand also came up in the conversation with Landsberg. Ka-band satellite communications require powerful amplifiers that send the signal thousands of kilometres into space. On a small drone or a manpack system with limited on-board power, this is no trivial requirement. The Viper Ka addresses this with intelligent power management: it switches between full-duplex, receive-only and standby modes, optimising energy consumption over the entire mission.

From manpack to naval vessel

Scalability is one of the system's main strengths. The airborne configuration for tactical UAVs is the reference version, but the basic principle can be transferred to other platforms, with corresponding performance limitations. The Viper Ka is therefore also intended as a manpack terminal for individual soldiers in the field and for naval vessels. Armoured land vehicles are also part of the targeted range of applications.