Civil Aviation Authority issues guidance as counter-drone technology disrupts UK airspace

The UK Civil Aviation Authority (CAA) has issued sweeping guidance to airspace users following a “dramatic increase” in radio frequency (RF) jamming activities conducted by military and law enforcement agencies.

The surge in intentional signal disruption is primarily driven by the rapid expansion of the remotely piloted aircraft systems (RPAS) sector—commonly known as drones—and the corresponding urgency to deploy counter-measures against their potential misuse.

RF jamming is a technique designed to deliberately block or interfere with radio signals to disrupt information flow. While typically deployed to inhibit the command, control, and navigation systems of target drones, these powerful radio signals can indiscriminately impact other aviation systems operating in close proximity.

According to the CAA, regular military, police, and operational deployments can disrupt a broad range of critical frequency bands. Chief among these are Global Navigation Satellite Systems (GNSS), which encompass GPS, GLONASS, and Galileo networks. Because these satellite constellations operate on a limited number of frequency bands, a single jamming event risks compromising most receivers within a significant radius.

The scale of these disruptions can be vast. Historically, large-scale military trials have impacted GPS receivers up to 100 nautical miles away from the jamming source, reaching altitudes of up to 40,000 feet above mean sea level.

The disruption is not limited to satellite navigation. Jamming also frequently affects the Industrial, Science and Medical (ISM) bands, which operate on a licence-exempt, “no interference, no protection” basis. Interference in these bands affects everyday tech alongside critical aviation equipment, disabling Wi-Fi and Bluetooth devices, drone video feeds, and electronic conspicuity devices used by pilots to maintain situational awareness and avoid mid-air collisions.

For drone operators, the consequences of signal interference can be severe. Aircraft may fail to receive commands or receive corrupted data, meaning the drone may not respond correctly to the pilot. Furthermore, vital automated safety functions, such as ‘return to home’ protocols and digital geofencing capabilities, can be entirely inhibited.

For manned aviation, pilots relying on moving map applications may see inaccurate or incorrect positions displayed on their screens. Loss of GPS data may also inhibit crucial airspace warnings. The CAA has instructed operators not to rely solely on GNSS systems during known jamming trials and mandates that they must be prepared to revert to conventional, alternative forms of navigation, such as dead reckoning. Air traffic controllers are also being placed on alert to assist aircraft that may require navigation assistance during these periods.

To mitigate the safety risks, the CAA requires the sponsors of jamming activities to properly coordinate and notify affected airspace users. Planned jamming events are typically announced via Notices to Aviation (NOTAMs) and Aeronautical Information Circulars (AICs), which outline predicted geographical impact areas. To help pilots prepare, the CAA categorises these impact zones into three tiers of risk: Green (interference unlikely), Amber (interference possible), and Red (interference probable).

Beyond large-scale military trials, the CAA notes that lower-power jamming equipment is now regularly deployed for operational reasons, often to protect major public events and mass gatherings, or in unplanned emergency responses to specific threats.

Major scheduled military activities contributing to these disruptions include “Exercise Enduring Look” at RAF Spadeadam, and comprehensive GNSS jamming and spoofing trials at the Sennybridge Training Area in Wales, demonstrating the ongoing nature of these electronic exercises across the UK. Pilots experiencing unnotified jamming are urged to report the performance issues to the CAA to assist in identifying illegal jamming activities or improving future impact predictions.