Drone detection radar

How it works

A radar transmits radio waves and processes the echoes. The delay gives range, the antenna direction gives bearing, and the frequency shift (Doppler effect) gives speed.

A small drone has a tiny radar cross section (RCS) – roughly comparable to a bird. Drone detection radars are therefore optimised for small, slow, low-flying targets, exactly where conventional air surveillance radars struggle.

AESA. Modern compact radars typically use an active electronically scanned array: the beam is steered electronically, with no moving parts. That enables fast scanning, simultaneous tracking of many targets, small size and high reliability.

Micro-Doppler. Spinning rotors add a characteristic, tiny frequency modulation to the echo. Analysing this "micro-Doppler signature" lets the system tell a drone from a bird – one of the most important tools against false alarms.

Strengths

• Detects drones flying pre-programmed routes in radio silence
• Precise range, speed, altitude and track
• Tracks multiple targets at once – essential against swarms
• Works at night and in fog
• Ideal source for automatic camera cueing (slew-to-cue)

Limitations

• Active emitter – a spectrum licence is typically required
• False alarms – birds, moving vegetation, vehicles; without classification a radar is unusable
• Urban clutter – buildings shadow and cause spurious reflections
• No identification – no type, no pilot; that needs RF and cameras
• Cost – higher investment and operating effort

Where it fits

High-value permanent sites where non-communicating drones are a real risk; open terrain; border and military sites; anywhere multiple simultaneous targets must be handled.