| Country of origin | UK |
|---|---|
| Manufacturer | Marconi |
| Introduced | 1982 |
| No. built | 22 |
| Type | early warning, tactical control |
| Frequency | 23 cm, L band (NATO D band) |
| PRF | 250 pps |
| Beamwidth | 2.8º horizontal, 1.5º vertical (S713) 1.6º/~3º (S723) |
| Pulsewidth | 10 μS (S713), 150 μS (S723) |
| RPM | 6 |
| Range | 256 nautical miles (474 km; 295 mi) on a 1 square metre (11 sq ft) target |
| Altitude | 150,000 ft (46,000 m) |
| Azimuth | 360º |
| Elevation | -2º to 30º |
| Precision | range resolution ~450 ft |
| Power | 3.3 MW (S713), 132 kW (S723) |
| Other Names | S713, S723, S743 AMES Type 90, AMES Type 91 S763/Ceselsa LANZA |
Martello is a family of phased array radar systems developed by Marconi Electronic Systems in the 1970s and introduced operationally in the early 1980s. They provided long-range early warning capabilities but also had the accuracy needed for interception plotting and "putting on" of other weapons systems like surface-to-air missiles. The name comes from the Martello towers that provided defence in earlier years.[1]
A key feature of the new design was its solution to measuring altitude. Earlier mechanically scanned 3D radars used multiple feed horns in a vertical stack, but this was difficult to make in a mobile form; when moved they would go out of alignment. Newer phased arrays used electronic phase shifters to sweep up and down to measure angles, but this required expensive electronics. Martello used fixed phase shifters to produce a pattern of eight stacked beams, recreating the multiple feed horn pattern in a small box that was inexpensive to implement.
The system was initially offered to the RAF, whose Linesman radar network was the subject of much concern over its survivability due to its fixed locations and single control centre in London. It was suggested it should be replaced as quickly as possible by a mobile, distributed system. Around the same time, NATO was beginning the process of upgrading their Europe-wide radar network, NADGE, and their basic requirements were similar to the UK's. Martello was conceived to fill both requirements.
The first S713 was introduced in 1978 and entered RAF service in 1982 as the AMES Type 90. Changes to the NATO specification led to the S723, introduced in 1984 and entering service with the RAF in 1986 as the AMES Type 91. The S723, and product-improved S743 version found a number of international buyers. At least 22 members of the S700 family were sold between the late 1980s and early 2000s. The Lockheed Martin AN/TPS-77 has replaced the Martellos in the UK,[2] as the AMES Type 92.