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Last Updated: Mon Jan 27 11:18:09 UTC 2014

Search and Acquisition Radars
(S-Band, X-band)

Technical Report APA-TR-2009-0101

by Dr Carlo Kopp, AFAIAA, SMIEEE, PEng
January, 2009
Updated July, 2009
Updated April, 2012
Text, Line Art © 2008 - 2012 Carlo Kopp

P-30 Periskop / P-35 Saturn / P-37 / 1L117/1L117M Bar Lock / Big Bar / Big Mesh

The Bar Lock series is one of the most widely exported Soviet era radars, and remains widely used especially in developing nations. Depcited a later model P-37 variant (Iskra).

An improved P-35M showing the characterstic stacked feeds (Vestnik PVO).

1L117M Specifications (Rosoboronexport)

P-37 Principal Specifications [A]
Operating Band [Ghz]
2.9 - 3.3 (5 channels)')" onmouseout="UnTip()">
Pulse Repetition Interval (PRI) [msec]
1.3 / 2.6
Pulse Repetition Frequency (PRF) [Hz]
375 - 750
Pulse Duration [usec]
Peak Power [MegaWatt]
Ave Power [kiloWatt]
Displayed Range [km]
Range Resolution [m]
Mainlobe Width [°]
Sweep Rate [RPM]
Deploy/Stow Time [min]

Основные тактико-технические характеристики [LEMZ]
Диапазон рабочих частот 10 см
Максимальная дальность, км 350
Угол обзора в вертикальной плоскости, град 28
Точность определения координат (СКО):  
       дальности, м 300
       азимута, угл. мин 10
       высоты, м 400
Разрешающая способность:  
       по дальности, м 500
       по азимуту, град 1
Коэффициент подавления отражений от местных предметов, дБ 25
Темп обновления информации, с 10
Количество сопровождаемых целей 200
Потребляемая мощность, кВт 50
Условия окружающей среды:  
       рабочий диапазон температур, °С от -40 до +50
       относительная влажность, % до 100 (в тропическом исполнении)
       скорость ветра, м/с до 25 без РПУ

VNIIRT 5N59/ST-68 / 19Zh6/ST-68U / 35D6/36D6/ST-68UM Tin Shield

Deployed ST-68UM Tin Shield, with the second trailer housing electronics and operator consoles.

The Tin Shield is semimobile and towed by a KrAZ-255 or -260 tractor, it can be deployed or stowed in one hour, or two with the mast. The design uses a large paraboloid cylindrical section primary reflector and a linear element array deployed on a pair of booms to provide electronic beam steering in elevation from -20 to +30 degrees, the antenna can perform a full 360 degree sweep in 5 to 10 seconds. With a transmitter peak power rating cited between 1.23 MegaWatts and 350 kiloWatts, the manufacturer claims the ability to detect a 0.1 square metre RCS target at 300 ft AGL out to 24.8 nautical miles, and at medium to high altitudes to 94.5 nautical miles. Clutter rejection is claimed to exceed 48 dB, and the system can track 100 targets. An IFF system is integrated in the radar.

The Tin Shield family of radars is diverse and over 1,000 have been built, with many variants widely exported. While the radar is best known as the acquisition component for the S-300P/PM/PMU/PMU1 SA-10/20 Grumble/Gargoyle SAM system, it has also been widely used as a general purpose medium/high altitude search radar. The radar is most commonly seen in its basic towed configuration, but can also be mounted on the 40V6M or 40V6MD mast system. It has been largely supplanted in newer S-300P/S-400 configurations by the LEMZ 96L6E.

19Zh6/ST-68U (Image © Miroslav Gyűrösi).

19Zh6/ST-68U (Image © Miroslav Gyűrösi).

An ST-68UM Tin Shield mounted on the 40V6M mast.

Tin Shield on display.

A stowed ST-68UM Tin Shield.

Another mode of deployment for the 19Zh6 Tin Shield is on a fixed elevated platform, the whole semi-trailer being so emplaced. This installation is static, but affords stability, access and elevation which cannot be achieved using a 40V6M/MD mast (Czech Army).

19Zh6/ST-68U consoles (Image © Miroslav Gyűrösi).

ST-68U Principal Specifications [A]
Operating Band
Pulse Repetition Interval (PRI) [msec]
0.7 - 1.3
Pulse Repetition Frequency (PRF) [Hz]
750 - 1500
Pulse Duration [usec]
6 - 12
Receive Interval [usec] 800
Peak Power [MegaWatt]
up to 2.5 (0.35 for ST-68UM)
Ave Power [kiloWatt]
Displayed Range [km]
150.0 or 75.0
Range Resolution [m]
Mainlobe Width [°]
Sweep Rate [RPM]
6 / 12
Deploy/Stow Time [min]
~60 (~120 with 40V6M)

LEMZ 5N66/5N66M/76N6 Clam Shell 

76N6 Nizkovysotniy Obnaruzhitel'

5N66M / 76N6 / 40V6M

The 5N66/5N66M/76N6 Clam Shell low level early warning and acquisition radar. It is an unconventional frequency modulated continuous wave design, using a split antenna arrangement with a large beak to prevent spillover from the transmitter. In configuration it is thus closest to the 5N62 Square Pair engagement radar used with the S-200/SA-5 Gammon SAM. Quoted performance figures include the detection of targets with an RCS as low as 0.02 square metres, at speeds of up to 1,400 kt, with a bearing resolution of 1 degree, velocity resolution of 9.3 kt and range resolution of 2.15 NM. Quoted RMS tracking errors are 0.3 degree in bearing, 4.7 kt in velocity and 1 NM in range. Chaff rejection performance is quoted at better than 100 dB, detection range is stated to be 50 NM for targets at 1,500 ft altitude, and 65 NM for 3,000 ft altitude. The transmitter delivers 1.4 kW of CW power at an unspecified carrier frequency, system MTBF is quoted at 100 hr with an MTTR of 0.5 hr.

This family of radars is best known as the acquisition component for the S-300P/PM/PMU/PMU1 SA-10/20 Grumble/Gargoyle SAM system. It has been largely supplanted in newer S-300P/S-400 configurations by the LEMZ 96L6E.

NIIIP 5N64S/64N6E/E1/E2 / 91N6E Big Bird

Early production 5N64S Big Bird A configuration - deployed.

The 64N6E Big Bird is the key to much of the improved engagement capability, and ballistic missile intercept capability in the later S-300P variants. This system operates in the 2 GHz band and is a phased array with a 30% larger aperture than the US Navy SPY-1 Aegis radar, even accounting for its slightly larger wavelength it amounts to a mobile land based Aegis class package. It has no direct equivalent in the West.

Like other components of the S-300PM system, the 64N6E has a number of unique and lateral design features. The radar antenna is mounted on a cabin, in turn mounted on a turntable permitting 360 degree rotation. Unlike Western phased arrays in this class, the 64N6 uses a reflective phased array with a front face horn feed, the horn placed at the end of the long boom which protects the waveguides to the transmitters and receivers in the cabin. The beam steering electronics are embedded inside the antenna array, which has around 2700 phase elements on either face. This Janus faced arrangement permits the Big Bird to concurrently search two 90 degree sectors, in opposite directions, using mechanical rotation to position the antenna and electronic beam steering in azimuth and elevation. This design technique permits incremental growth in output power as the only components of the system which have to handle high microwave power levels are the waveguide and feed horn.

The 64N6E is a frequency hopper, and incorporates additional auxiliary antenna/receiver channels for suppression of sidelobe jammers - NIIP claim the ability to measure accurate bearing to jamming sources. The back end processing is Moving Target Indicator (MTI), and like the Aegis the system software can partition the instantaneous sector being covered into smaller zones for specific searches. To enhance MTI performance the system can make use of stored clutter returns from multiple preceding sweeps. Detection ranges for small fighter targets are of the order of 140 to 150 nautical miles for early variants. Per 12 second sweep 200 targets can be detected, and either six or twelve can be individually tracked for engagements.

While the Big Bird provides an excellent acquisition capability against aerial and ballistic missile targets, the 5V55 missile was inadequate. The S-300PM/PMU1 introduced the 48N6 which has much better kinematics - cited range against aerial targets is 81 nautical miles, ballistic missile targets 21.5 nautical miles, with a minimum engagement range of 1.6 to 2.7 nautical miles. Low altitude engagement capabilities were improved - down to 20 - 30 ft AGL. The missile speed peaks at 2,100 metres/sec or cca Mach 6. The missiles can be fired at 3 second intervals, and Russian sources claim a single shot kill probability of 80% to 93% for aerial targets, 40% to 85% for cruise missiles and 50% to 77% for TBMs.

The latest variant is the 91N6E developed for the S-400 Triumf / SA-21 system. It is known to be a fully digital design with a higher peak power rating than the 64N6E2 to accommodate the longer ranging 48N6E3 and 40N6E missiles.

The new 91N6E is a derivative of the 64N6E Big Bird series. It is readily identified against the 64N6E by the use of the new build MZKT-7930 tractor. It retains the general configuration of its predecessors (Almaz-Antey).

64N6E deployed on display.

64N6E deployed in the field.

64N6E stowed and on the move.

 Характеристики (Russkaya Sila)
Зона обнаружения, град.
- по азимуту
- по углу места:
   - регулярный обзор
   - сопровождение
   - в специальном секторе


до 75
Дальность обнаружения аэродинамических целей типа МиГ-21, км 260
Точность определения координат
- по дальности, м
- по азимуту, мин
- по углу места, мин

Период обзора, с
- регулярный обзор
- сопровождение целей

Количество целей, координаты которых выдаются потребителю за каждый обзор 200
Время готовности с марша и время свертывания, мин 5

P-40/1S12 Bronya / Long Track

The P-40/1S12 was the primary acquisition radar for the now obsoleted 2K11 ZRK Krug / SA-4 Ganef, although the radar was often used to provide track data for other battlefield SAM systems.

1S12 Principal Specifications [A]
Operating Band [GHz]
2.,2 - 2.3
Pulse Repetition Interval (PRI) [msec]
1.25 / 2.5
Pulse Repetition Frequency (PRF) [Hz]
400 / 800
Pulse Duration [usec]
Receive Interval [usec] 1.24 / 2.49
Peak Power [MegaWatt]
~ 2.0
Ave Power [kiloWatt]
 2.0 - 3.0
Displayed Range [km]
Range Resolution [m]
Mainlobe Width [°]
Sweep Rate [RPM]
4  - 5

9S15/9S15MV2 Obzor 3 / Bill Board A/B

9S15 Bill Board (Image © 2009, Sergey Kuznetsov).

The fully mobile 9S15/9S15M Obzor 3 / Bill Board acquisition radar is a mechanically rotated 3D radar system, with electronic beam steering in elevation and an IFF array. It provides long range early warning of aerial threats and low end TBMs such as the Scud A and Lance for the S-300V/VM / SA-12/23 Giant/Gladiator SAM systems.

There are a number of configurations, associated with specific block upgrades to the S-300V / SA-12 series system, including a variant specific to the S-300VM / SA-23 system, the 9S15MV/MVZ

The 9S15 has two basic modes of operation. The first is optimised for a 12 second sweep and is claimed to provide a 50% probability of detecting a fighter sized target at 130 nautical miles.

The second mode employs a faster 6 second sweep period, and is used to detect inbound TBMs and aircraft, with a reduced detection range of about 80 nautical miles for fighters, and 50 to 60 nautical miles for TBMs like the Scud A or Lance.

Cited range against aerial targets for the improved Bill Board B is in excess of 170 nautical miles for fighters.

Russian sources are unusually detailed on ECCM techniques used, claiming the use of three auxiliary receiver channels for cancelling sidelobe jamming, automatic wind compensated rejection of chaff returns, and provisions in the MTI circuits to reject jamming. A facility for precise angular measurement of jamming emitters is included. RMS tracking errors are quoted at 250 metres in range and about 0.5 degrees in azimuth/elevation, with the ability to track up to 200 targets.

Cited RF performance for the baseline 9S15M is an average power of 8 kiloWatts produced by a TWT, and receiver sensitivity of 10-13 Watts.

The system has an integral gas turbine electrical power generator for autonomous operation - a feature of most S-300V components.

This radar provides a highly mobile 3D search and acquisition capability, but is limited in low level coverage footprint by its antenna elevation. Its limited scan rate makes it unusable for high performance IRBM acquisition and tracking, which is the primary role of the 9S19 High Screen radar.

Specifications (Rosoboronexport)

9S18/9S18M/M1/M1-1 Kupol / Tube Arm / Snow Drift

9S112 Kupol M2 Acquisition Radar

9S18M1 Snow Drift (Wikipedia image).

9S18M1 Snow Drift.

Specifications (Rosoboronexport)

Proposed wheeled configuration of the 9S112 for the Buk M2E hosted on the MZKT-9622 vehicle.

9S19/9S19M/M2 Imbir / High Screen A/B

9S19 Imbir / High Screen A deployed (Image © 2009, Sergey Kuznetsov).

The specialised 9S19 Imbir is a high power-aperture, coherent, X-band phased array designed for the rapid acquisition and initial tracking of inbound ballistic missiles within a 90 degree sector. To that effect it uses a large passive phase technology transmissive array, using a conceptually similar space feed technique to the MPQ-53 and 30N6 series radars, producing a narrow 0.5º pencil beam mainlobe. The primary search waveform is chirped to provide a very high pulse compression ratio intended to provide very high range resolution of small targets.

The design uses a 16 kiloWatt ave Travelling Wave Tube (TWT) source, very low sidelobes and frequency hopping techniques to provide good resistance to jamming.

Three primary operating modes are used. In the first the 9S19 scans a 90º sector in azimuth, between 26º and 75º in elevation, to detect inbound Pershing class IRBMs within a 40 to 95 nautical mile range box, feeding position and kinematic data for up to 16 targets to the 9S457 command post. In this mode the transmissive array is tilted back to 35º.

The second mode is intended to detect and track supersonic missiles such as the AGM-69 SRAM, and sweeps a narrower 60º sector in azimuth, between 9º and 50º in elevation, within a range box between 10 and 90 nautical miles, generating target position and velocity updates at 2 second intervals.

The third mode is intended to acquire aircraft in severe jamming environments, with similar angular and range parameters to the second mode. In this mode the transmissive array is tilted back to 15º.

The radar is claimed to produce RMS angular errors of around 12 to 15 minutes of arc, and a range error of a mere 70 metres (at max range 0.04%!). The peak power rating remains undisclosed. Cited range performance for the 9S18M2 High Screen B is 250 km, versus 175 km for the earlier High Screen A.

In function the 9S19 most closely resembles much newer Western X-band ABM radars, but is implemented using seventies generation antenna and transmitter technology, and is fully mobile unlike the semimobile US THAAD X-band radar, and Israeli Green Pine.

9S19 Imbir deploying (Image © 2009, Sergey Kuznetsov).

9S19 Imbir

The S-300V/SA-12 uses two acquisition radars. The Bill Board acquires airborne targets and tactical ballistic missiles, while the X-band High Screen phased array acquires these, supersonic cruise missiles and intermediate range ballistic missiles. Both radars are designed to operate in heavily jammed environments (Author).

Specifications (Rosoboronexport)

64L6E Gamma-S1E

The 64L6E Gamma-S1E is a mobile,  planar array 3D radar.  The radar comprises the M1 vehicle, mounting a phased-array antenna with an integral turntable, a transceiver and a ground radar interrogator; the M2 vehicle, mounting control, signal processing, data display, recording/print out facility, communications and datalink equipment; and the M3 vehicle, carrying spare parts, tools and accessories set; as well as two electric power plants in trailers, towed by M1 and M2 vehicles.

Provision is made for a four-operator remote control facility to control the radar from a distance of up to 1 km via a fibre-optic line or from 15km-distance - via a radiolink.

The Gamma-S1E is an all-weather radar operating in various climates at temperatures between -50°C and +50°C, in relative humidity totalling 98%, wind speed equalling up to 25 m/s and above-sea altitude amounting to 2,000 m. The radar is fitted with an automated testing/monitoring equipment, air conditioning, automatic fire-alarm and fire-extinguishing systems, other technical support assets.

(Roboronexport catalogue cited).

Specifications (Rosoboronexport)

The most recent variant of the Gamma S1 series is hosted on an all terrain 6 x 6 BAZ-690921 chassis to provide improved off-road mobility compared to the KrAZ-260 series. The antenna head is carried by one vehicle, the equipment cabin another (images Said Aminov Vestnik-PVO).

Gamma S1/S1E radar vehicle - note the antenna fold above the attachments for the hydraulic rams. Below, equipment cabin vehicle with operator consoles, note the large ECS vent duct.

Imagery Sources: Russian Internet, Chinese Internet, Almaz-Antey, LEMZ, VNIIRT, Author
Line Artwork: © 2000, 2007, 2008, 2009 Carlo Kopp

Technical Report APA-TR-2009-0101

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