TheRP-23Sapfir (NATO codename:High Lark) was aSovietlook-down/shoot-downradar system. It was developed byPhazotron specifically for theSoviet Air Forces (VVS) newMiG-23fighter aircraft and used in conjunction with theVympel R-23 (NATO codename: AA-7Apex)beyond visual rangeair-to-air missile.
The initial production version, the Sapfir-23L (L -Lyogkiy or lightweight) pulse radar was first carried on the MiG-23 Edition 1971. Using a twist-Cassegrain antenna 800 mm (31 in) in diameter, it used a continuous-wave target illuminator channel to provide guidance for thesemi-active radar homing (SARH) R-23R missile. However, as an interim variant it was considered unreliable and lacked the look-down/shoot-down capability of later Sapfir radars; it could only guide missiles onto targets flying above 1,000 m (3,300 ft).[1][2]
Equipping the MiG-23M, the improved Sapfir-23D had look-down/shoot-down capability and could guide both R-23R and R-23T missiles.[3] It was not a trueDoppler radar but used the less effective "envelope detection" technique common toWestern radars of the 1960s.[4] The technology was reportedly taken from the F-4JAN/AWG-10 radars captured in Vietnam in 1967.[2] The Sapfir-23D had a detection range of approximately 45km against a high-flying, fighter-sized target.[4] All Sapfir-23Ds were eventually updated to the definitive Sapfir-23D-III during field upgrades.[3]
The definitive version of the first-generation Sapfir-23s, all MiG-23Ms were fitted with the Sapfir-23D-III starting in 1975. Working in the 3cm wavelength and with a carrier frequency of about 9GHz, it had a detection range of about 45km against a high-altitude fighter-sized aircraft during ahead-on engagement, and between 10 and 20km in look-down mode during atail-chase engagement. Against bomber-size targets these ranges were 55km and 15 to 20km respectively. However, in look-down/shoot-down mode targets flying slower than 60 km/h (37 mph) would not be detected.[2]
A re-designation of the Sapfir-23D-III carried on the export-specific MiG-23MF. Those which were sold toThird World clients had downgraded performance and lackedelectronic counter-countermeasures (ECCM).[3][5]
Equipping the newer MiG-23ML, the Sapfir-23ML was an improvement upon the Sapfir-23D-III, being more reliable and with superior look-down/shoot-down capability.[6] It had a maximum detection range of 65km against a fighter-sized target at high altitude, reduced to 25km in look-down mode.[7]
An improved version of the Sapfir-23ML with better range, reliability, ECCM and the capability to guide the updated R-24R/T air-to-air missiles. It also had a frequency spacing feature that prevented multiple radars from interfering with each other's operation, allowing for group-search patterns to be conducted.[3]
A downgraded version of the N003 carried on MiG-23MLDs exported to Syria.[8] It was also carried on export versions of the MiG-23ML. The N003E had no ability to detect or track targets in a tail-chase engagement, relying on the fighter'sIRST instead. It's field of scan was +/- 30° to either side of the fighter's nose and +/- 6° in elevation.[9]
The ultimate version of the RP-23, the N008 was carried on the MiG-23MLD used by the VVS. Weighing 360 kg (790 lb), it had an average emitting power of 1kW and peak output of 60kW. It featured improved detection range, reliability, ECCM, look-down/shoot-down over rough terrain, and a close air combat mode with vertical-scan capability. Search range against high-altitude targets was 75km for a bomber-sized target and 52km for a fighter-sized target; in look-down mode it was 23km for both target types, except for fighter-sized targets in a head-on engagements in which case it was 14km. Tracking range against high-altitude targets was 52km for bomber-sized and 39km for fighter-sized targets; in look-down mode it was 23km for bombers, while for fighter-sized targets it was 15km in tail-chase or 9km in head-on engagements. The scan field was limited to 60° x 6°, although it could be steered up to 60° left and right to expand the search area.[10]
This derivative of the Sapfir-23ML was designed specifically for the MiG-23Pinterceptor, although initial models were unreliable and required additional maintenance.[11] It had slightly improved look-down/shoot-down, including againstcruise missiles.[7][2]