The Euroradar Captor is a next-generation mechanical multi-mode Pulse Doppler Radar designed for the Eurofighter Typhoon. Development of Captor led to the AMSAR (Airborne Multirole Solid State Active Array Radar) project which eventually produced the CAESAR (Captor Active Electronically Scanned Array Radar), now known as Captor-E.

Development

Early development In June 1985, discussions began amongst various corporations to sound out the possibility of cooperation on the radar for the EFA, the project that would later become the Eurofighter. The United Kingdom chose Ferranti as the leading contract partner, Germany AEG-Telefunken and Italy FIAR. Spain, which had no radar experience, played only a minor role, later selecting Eesa as the main contractor. Towards the end of June 1985, a memorandum of understanding was signed between the UK, Germany, France, Italy and Spain to develop a joint radar for the EFA. France had already indicated at the time that it intended to withdraw from the programme. The French company Thomson-CSF was thus faced with a dilemma, as it would have liked to participate in an EFA radar.flightglobal: Five study EFA radar, 29 June 1985 (PDF; 131 kB) Therefore, in 1987, Thomson-CSF negotiated with Ferranti to secure a share of the work. Specifically, the travelling-wave tube was to be supplied which was possibly the same one that was to be used in the Rafale. In March 1987, Ferranti and AEG sent their offers to Eurofighter GmbH.

Ferranti presented its ECR-90, based on the Blue Vixen, as early as 1986, while AEG offered the MSD-2000 "Emerald", which was based on the AN/APG-65.flightglobal: EFA radar battle: new versus now, 6 September 1986 (PDF; 2,4 MB) Ferranti's main argument was that a European fighter aircraft should also be equipped with a European radar. Ferranti had already been working with Thompson-CSF, Inisel and FIAR on the development of the radar since 1983. France withdrew with Thompson-CSF in June 1985, followed a year later by AEG. AEG wanted to offer a system based on the APG-65, as the company already had the production licence for this. There was still speculation as to whether Thorn-EMI would offer the AN/APG-68, but this did not end up happening. Both bidders submitted two-part offers: one that fully met the tender requirements and a reduced low-cost variant. Ferranti and FIAR offered the ECR-90 and the Super Vixen, AEG and GEC Marconi the MSD-2000 and the APG-65, but both high-tech offers were too expensive and the low-cost alternatives were deemed insufficient.

As a result, a new tender was launched. This time, the performance requirements were slimmed down and the manufacturers were also asked how the costs could be reduced. The requirements were also less stringent in order to fuel the inventive spirit of the engineers. The two new tenders were submitted in February 1988:

ECR-90: The European Collaborative Radar 90 was offered by Ferranti in the variants -90, -90A and -90B. The detection range was always the same, only the capabilities were to be integrated bit by bit. The main argument was again that the radar would account for a significant proportion of the costs of the EFA, and thus a European in-house development would enable higher added value in Europe. To reduce risk, the ECR-90 was to be based on the Blue Vixen of the BAE Sea Harrier FA2, which was already AMRAAM-capable in order to send target updates to the missiles. For the Blue Vixen, two planar antenna designs were tested: one made of a light metal alloy and one formed from an aluminised carbon fibre plate; the latter was rejected due to the higher costs and uncertainty regarding durability. The choice was left open for the ECR-90. The antenna drive was based on the Blue Vixen and PS-05 of the Saab 39, and corrected pitch and roll movements with 0.5 hp samarium-cobalt motors. There was no roll control: roll angles were compensated electronically. The coupled-cavity travelling wave tube was to be supplied by Selenia or Thomson-CSF. The signal processing and processors were taken over from the Blue Vixen. Since the software development of Blue Vixen accounted for about 80% of the development costs, and about 50% of the software for the ECR-90 was to be taken over, savings opportunities were seen here. Blue Vixen only had 11 of the required 31 radar modes. The 32-bit signal processor, however, was to be twice as fast and supplied by Hughes, IBM or Ericsson. The Blue Vixen's D80 achieved around 500 MIPS. The computing modules were housed in metal cassettes that acted as heat sinks and had air flowing through the centre. While the Blue Vixen consisted of 13,790 parts, the ECR-90 was to consist of only 13,000 parts. MSD-2000: The Multimode Silent Radar 2000 from AEG and GEC Marconi was based on the APG-65. This was a logical progression as the APG-65 had been planned for the EFA predecessor TKF-90, which is why the weight, volume and energy specifications of the EFA radar were also adopted from the TKF-90 program. Marconi also came to the conclusion that a new development would not be possible in the time available, which is why the APG-65 of the F-18 was accepted as the base model. The APG-65 already had 28 of the required 31 radar modes and the AMRAAM capability, meaning that 80% of the software could be adopted. A further 10% had to be reprogrammed and another 10% newly programmed. The additional programming related almost exclusively to the three missing modes "Non-Cooperative Target Recognition", "Visual Identification" and "Slaved air-to-air acquisition". In addition, the number of targets in TWS mode and the ECCM capability were to be improved. Compared to the APG-65, the antenna was to be enlarged from 68 cm to 75 cm and the radiation power doubled. The receiver sensitivity was to be increased, the antenna was to be equipped with D/F-band dipoles for a NATO IFF system, and the signal processor was to be replaced with a faster model from Marconi. New samarium-cobalt motors were planned for the antenna drive so as not to reduce the antenna speed. Although the transmitter power was to be doubled compared to the APG-65, the transmission power was always to be kept as low as possible to prevent detection. The number of plug-in cards was to be reduced from 21 to 7, but 25% of the computing and memory capacity was to remain free. The remaining 17 free slots would then be available for expansion. The radar processor was to be adopted from the AI.24 Foxhunter radar of the Tornado ADV, which was based on a 32-bit Motorola 68020, in order to double the computing power. In total, less than 15% of the radar would come from the US.

The radar software was to be programmed in Ada, as was the entire EFA software. The US was rather critical of the required technology transfer for the MSD-2000 when it was negotiated in May 1988,flightglobal: US hampers EFA radar bid, 28 May 1988 (PDF; 2,3 MB) but nevertheless agreed to it in August of that year. The schedule now envisaged completing the first airworthy radars in 1992, as the first flight of the EFA was planned for 1991, and starting series production in 1996. Spain was now in favour of the MSD-2000, as the cost and timeframe seemed the most realistic.flightglobal: EFA radar transfer agreed, 27 August 1988 (PDF; 2,2 MB) After October 1988, the decision was made,flightglobal: EFA radar choice nears, 22 October 1988 (PDF; 285 kB) with Ferranti's ECR-90 winning the race but not being chosen.

Since Germany did not agree with the decision, German Defence Minister Gerhard Stoltenberg met with British Defence Secretary Tom King in mid-1989. They agreed to commission a study into whether the MSD-2000 could be adapted to British requirements after all. At the same time, the UK Ministry of Defence launched a study into how the partner countries, excluding Germany, could develop their own radar for the EFA.flightglobal: EFA – UK looks at three-nation radar, 7 October 1989 (PDF; 1,3 MB) The MSD-2000 study was negative, but Germany still refused to give in on this issue. As no agreement could be reached after 18 months, the UK and Germany called on the industry to find a solution. In December 1989, Ferranti held talks with Telefunken System Technik (formerly AEG until Daimler took over the company) to co-operate on the ECR-90 and resolve the German resistance. At the same time, the industry warned politicians of rising costs due to the delays. Eurofighter GmbH then sent letters to all four partner countries and NETMA stating that all additional costs would be passed on to them. This was important as the EFA radar was to be awarded as a fixed-price contract and the companies involved were to be reimbursed for the delays. At the beginning of 1990, GEC Marconi, which was working on the MSD-2000, swallowed up Ferranti, which was designing the ECR-90, a decision that was underwritten by the British government. Ferranti's labs became the new GEC Ferranti in 1990, and then BAE Systems Avionics when GEC's various military electronics divisions - Ferranti, Marconi and Elliott Brothers - were merged. Plessey, which manufactured the EFA's missile detectors, was taken over by a consortium of GEC Marconi and Siemens. This signalled a relaxation on the radar front. In early 1990, GEC-Ferranti was finally declared the winner of the EFA radar competition and awarded a £300m contract. In mid-1990, GEC-Ferranti negotiated with Ericsson to remove the company from the ECR-90 Euroradar consortium and use the Motorola 68020 processors of the MSD-2000 instead. In a comparison, its signal processing proved to be significantly more powerful. This in turn was seen as a problem by Germany, as the redesign of the ECR-90 meant that delays and further cost increases were unavoidable.

Hughes sued GEC for $600 million for its role in the selection of the EFA and alleged that it used Hughes technology in the ECR-90 when it took over Ferranti. It later dropped this allegation and was awarded $23 million; the court judged that the MSD-2000 "had a real or substantial chance of succeeding had GEC not [tortiously] intervened... and had the companies, which were bound by the Collaboration Agreement, faithfully and diligently performed their continuing obligations thereunder to press and promote the case for MSD-2000."

Since these events, further mergers have taken place in the industry. Parts of BAE Systems Avionics were merged with Galileo Avionica to form SELEX Galileo in 2005 which in turn then merged with other Finmeccanica defence electronics companies in 2013 to create Selex ES (merged in turn in Finmeccanica, rebranded Leonardo since 2017). The development effort is now organized under the Euroradar consortium, consisting primarily of Selex ES, as well as Airbus and Indra.

The ECR-90 was renamed CAPTOR when the project passed the production contract milestone.

Captor-E AESA

In 1993 a European research project was launched to create the Airborne Multirole Solid State Active Array Radar (AMSAR); it was run by the British-French-German GTDAR ("GEC-Thomson-DASA Airborne Radar") consortium (now Selex ES, Thales and Airbus respectively). This evolved into the CAESAR (Captor Active Electronically Scanned Array Radar), now known as Captor-E AESA.