| Country of origin | UK |
|---|---|
| Manufacturer | Plessey |
| Introduced | 1975 |
| No. built | 23 |
| Type | 3D radar, early warning |
| Frequency | S-band, 2915 to 3055 MHz |
| PRF | 250 pps |
| Beamwidth | 1º horizontal 3º vertical |
| Pulsewidth | 36 μS |
| RPM | 6 rpm |
| Range | 260 nautical miles (480 km; 300 mi) |
| Diameter | 12 by 12 metres (39 by 39 ft) |
| Azimuth | 360º |
| Precision | 40 m range, 0.16º azimuth |
| Power | 1.1 MW |
| Other Names | AMES Type 94 |
The AR-3D was a military air traffic control and early warning radar developed by Plessey and first produced in 1975. It used a pencil beam and simple frequency scanning system known as "squint scan" to produce a low-cost 3D radar system that was also relatively mobile. About 23 were produced in total and found sales around the world into the early 1980s.
The frequency scanning system had the disadvantage that a target aircraft would always be "painted" by the same frequency signal, which made the task of jamming the radar simpler. This limited its sales prospects to military users, and shortly after delivering the AR-3D the company began negotiations with the US company ITT-Gilfillan to incorporate their multi-frequency scanning with the AR-3D's receivers and display systems to produce the Plessey AR-320.