{{Short description|Type of multimode aircraft radar}} The '''RDM (Radar Doppler Multifunction)''', also known as the '''Cyrano 5''', is a French multimode pulse-Doppler radar developed by Thomson-CSF (now Thales) for export variants and early French models of the Mirage 2000 fighter aircraft. It is an evolution of the Cyrano IV installed on the Mirage F-1 and in turn was developed into the '''RDI''' ('''Radar Doppler à Impulsions'''), a specialist air-to-air radar for French Mirage 2000 interceptors, and the multimode '''RDY''' (Radar Doppler Multitarget), which could track more targets at a time and added further air-to-ground modes.
==History== The first prototype of the RDM flew in January 1980 and production deliveries began in early 1983.<ref name=flight19830402>{{cite news | title=RDM enters production for Mirage 2000 | url=http://www.flightglobal.com/pdfarchive/view/1983/1983%20-%200550.html | pages = 850–1 | newspaper=Flight International | date=2 April 1983}}</ref> Thomson funded development of the RDM from the Cyrano IV at a cost of FFr350m (~US$50m); the RDI air intercept derivative was funded by the French government.<ref name=flight19830402 /> The RDM was intended for export Mirage 2000's and the first 50 for the French Air Force; the remaining 150 French Mirage 2000C's would have the RDI.<ref name=flight19830402 /> In the end only 37 aircraft were fitted with the RDM, the first production RDI was delivered in December 1986.<ref>{{Citation | url=https://books.google.com/books?id=cxtFAQAAIAAJ&q=RDI | title=article | newspaper=Journal of Defense & Diplomacy | volume = 5 | year=1987 | page=62}}</ref> The two radars are interchangeable in the aircraft but have little in common electronically; the biggest difference is that the RDI increases the look-down/shoot-down range in pulse doppler mode from {{convert|20|nmi|km}} to {{convert|50|nmi|km|abbr=on}},<ref name=flight19830402 /> and supports the improved Super 530D missile. Allegedly the French Air Force would have preferred to wait until the RDI was ready and have an all-RDI fleet, but the government insisted that they take aircraft with RDM so that it could be marketed abroad as the front-line radar of France.<ref>{{cite journal | url=http://www.disam.dsca.mil/pubs/Vol%208-3/Anastassopulos%20%26%20Dussage.pdf | title=French 'Savoir-Faire' in Selling Arms: a New Way of Doing Business | first1=Jean-Pierre | last1=Anastassopoulos | first2=Pierre | last2=Dussage | journal = Long Range Planning: The International Journal of Strategic Management | volume=8:3 | pages=70–77 | date=Spring 1986 }}</ref>
==Design== RDM operates in the X-band with a coherent travelling-wave-tube transmitter and an inverted-Cassegrain antenna {{convert|655|mm|in|abbr=on}} in diameter.<ref name=flight19830402/> The RDM operates in air defence/air superiority, strike and air-to-sea modes. In the air-to-air role, the system can look up or down, range while searching, track-while-scan, provide continuous tracking, generate aiming signals for air combat and compute attack and firing envelopes. For the strike role it provides real-beam ground-mapping, navigation updating, contour-mapping, terrain-avoidance, blind let-down, air-to-ground ranging and Ground Moving Target Indication (GMTI).
In the maritime role it provides long-range search, track-while-scan and continuous tracking and can designate targets for active missiles. For air-to-air combat, the RDM provides a 120° cone of coverage, the antenna scanning at either 50 or 100°/s, with ±60, ±30 or ±15° scan. For air-to-air gun attacks, the 3.5° beam can be locked to the target at up to {{convert|19|km|nmi|abbr=on}} range, with automatic tracking within the head-up display field of view, or in a 'super-search' area, or in a vertical search mode. Options include a Continuous Wave Illuminator (CWI) and Doppler Beam Sharpening (DBS). Comprehensive Electronic Counter-Countermeasures (ECCM) are incorporated.
The manufacturers claim that RDM will detect 90% of 5 m<sup>2</sup> RCS fighter-sized targets out to {{convert|50|nmi|km|0|abbr=on}} in clear air using a four-bar search pattern over 120° in azimuth, and {{convert|60|nmi|km|0|abbr=on}} with a single-bar pattern over 30° in azimuth, dropping to {{convert|20|nmi|km|abbr=on}} in pulse-Doppler look-down mode.<ref name=flight19830402 /> RDI uses a higher pulse-repetition frequency for its dedicated interception role, increasing clear-air range to around {{convert|66|nmi|km|abbr=on}} and {{convert|50|nmi|km|abbr=on}} is possible in look-down mode.<ref name=flight19830402 />
==See also== * AI.24 Foxhunter - contemporary British radar on the Tornado F3 * AN/APG-63 radar family - contemporary US radar on the F-15 Eagle * RBE2 - Radar à Balayage Electronique 2, radar on the Rafale
==Notes and references== {{reflist}}
Category:Aircraft radars Category:Military radars of France Category:Post–Cold War military equipment of France