Gamma De AESA RADAR of Bangladesh

Gamma De AESA RADAR of Bangladesh

Bangladesh ordered 2 gamma de aesa radar


VNIIRT Gamma DE AESA deployed configuration (above) and stowed configuration (below). Three subtypes exist, the D1/D1E, D2/D2E, and D3/D3E with differing module power ratings and range performance. Depicted is the towed configuration with a 20 minute deploy/stow time. VNIIRT disclosed in 2007 that a self-propelled variant was available, with a 5 minute deploy/stow time compatible with the S-300PMU2 and S-400 SAM systems. To date no imagery of the self-propelled variant has been disclosed.

                                                                   

The VNIIRT Gamma DE is a solid state long range L-Band 3D Active Electronically Steered Array (AESA) search and acquisition radar intended to support interceptors and Integrated Air Defence Systems. It is intended to detect and track aircraft, cruise missiles, precision guided munitions and tactical ballistic missiles at medium and high altitudes. The manufacturer cites two basic operating modes "iso-range" and "iso-altitude".

Gamma DE installations can be supplied with three different AESA module power ratings, yielding the D1/D1E, D2/D2E and D3/D3E variants. Cited MTBF in recent literature is ~1,000 hrs which is consistent with mature AESA technology.
                                                                 

The VNIIRT designers paid considerable attention to operation in high threat environments. A number of design features were introduced for this reason:

1. The ability to concentrate emitted power into search sectors which are being subjected to jamming, to decrease the J/S ratio.
2. Wideband pulse-to-pulse automatic frequency hopping with automated avoidance of jammed frequencies (i.e pre-transmit sniffing), employing a spectrum analyser.
3. Signal processing functions to reject incoherent signals received in the mainlobe, such as jammers or other interfering in-band emitters.
4. Multichannel rejection of jamming. This is likely to have been implemented by forming nulls in the mainlobe.
5. Jammer rejection by sidelobe blanking.
6. Adaptive multichannel pulse Doppler filtering for clutter rejection. While VNIIRT literature describes this as DMTI, it is not clear whether the technique used is conventional DMTI or pulse Doppler.
7. Rejection of jammers and signals with low radial Doppler shifts relative to the radar.

Another very modern feature in this design is the use of Non-Cooperative Target Recognition (NCTR). This is claimed to be performed by the analysis of backscatter power levels, correlation against known signatures, and the flight trajectory characteristics of the track. Helicopters are recognised by analysing the advancing and receding rotor blade Doppler shifts.

To defeat anti-radiation missiles and Emitter Locating Systems, the Gamma DE employs short burst transmissions, with radar emission timing slaved to the Gazetchik E emitting anti-radiation missile decoy system. In addition chaff, smoke generators and infrared decoys are employed to seduce missiles with active radar, electro-optical or imaging infared seekers. The Gazetchik E is claimed to achieve a 0.85-0.95 Pk against anti-radiation missiles. It is worth noting than many such missiles do not have the band coverage to home in on an L-band emitter such as the Gamma DE.

Like many Western L-band radars, such as the MESA, the Gamma-DE has an integrated IFF function in the primary array, supporting Mark XA and XII modes. This is performed using the VNIIRT developed Voprosnik-E secondary radar, embedded in the Gamma-DE antenna system.

The AESA design provides cited mainlobe steering angles of up to ±60° in azimuth and elevation. VNIIRT claim a robust detection range of up to 600 nautical miles against high elevation angle ballistic missile targets. Like Western phased array radars the Gamma DE is capable of adaptively interleaving search and track beams, and nulling particular angular sectors which are subject to jamming. Modes include high update rate search waveforms in narrow solid angles, providing for high quality tracking of high speed closing targets.

A single Gamma DE system comprises a towed antenna head trailer with the 1280 element 8 x 5.2 metre AESA on a turntable, a semi-trailer radar cabin with electronics and operator stations, and a dual redundant 16 kiloWatt diesel generator. An option cited for the Gamma DE is deployment of the radar head on the 24 metre 40V6M or 40 metre 40V6MD semi-mobile mast systems. The latter are carried by semi-trailer and typically towed by a MAZ-537 or other tractor. Cited time to deploy the basic demonstrator configuration is 1.5 hrs. More recent (2007) VNIIRT data states 20 minutes to deploy the towed configuration, and 5 minutes to deploy a self-propelled configuration carried on a truck. This qualifies the towed Gamma DE as mobile, and the self-propelled configuration as "shoot and scoot".

To date no details of the self propelled variant have been disclosed. Given the size and weight of the Gamma DE antenna system, the configuration is likely to be similar to that of the 91N6E Big Bird rather than 96L6 , most likely using the MZKT-7930 tow tractor, and a gas turbine generator equipped semi-trailer for the antenna head and equipment cabin.

In the towed variant, radiofrequency datalinks permit the cabin to be located up to 1 km from the AESA, and additional datalinks permit up to 15 km separation between the cabin and an IADS command post. For semi-hardened revetted deployment optical fibre cables are available.

Almaz-Antey literature on the S-400 / SA-21 system states that compatible interfaces are available between the S-400 battery and the Gamma DE system. The azimuthal tracking accuracy of 0.17-0.2°, elevation accuracy of 0.2-0.3° and range accuracy of 60-100 metres make this radar eminently capable of providing midcourse guidance updates for a range of SAM systems. For comparison, the 64N6E Big Bird series used in the SA-20/21 has around twice the angular and range tracking error magnitude compared to the Gamma DE.