The 9K33 Osa (, literally "wasp"; NATO reporting name SA-8 Gecko) is a highly mobile, low-altitude, short-range tactical surface-to-air missile system developed in the Soviet Union in the 1960s and fielded in 1972. Its export version name is Romb. Description The Osa was the first mobile air defense missile system incorporating its own engagement radars on a single vehicle. All versions of the 9K33 feature all-in-one 9A33 transporter-launcher and radar vehicles which can detect, track and engage aircraft independently or with the aid of regimental surveillance radars. The six-wheeled transport vehicles BAZ-5937 are fully amphibious and air transportable. The road range is about 500 km. The 1S51M3-2 radar system on the 9K33 Osa TELAR received the NATO codename Land Roll. It was derived from the naval 'Pop Group' radar system but is smaller since it does not require the elaborate stabilisation system. An improved system, the Osa-AKM (NATO reporting name SA-8B 'Gecko' Mod 1) was first seen in Germany in 1980. It had improvements added to the launcher configuration, carrying six missiles in ribbed containers. The system is reported to be of the frequency-agile monopulse type. It consists of an elliptical rotating surveillance antenna mounted on top of the array, operates in H band (6 to 8 GHz) and has a 30 km acquisition range against most targets. The large pulsed J band (14.5 GHz) engagement antenna is mounted below it in the centre of the array and has a maximum tracking range of about 20 km. Mounted on either side of the tracking radar antenna is a small J band parabolic dish antenna to track the missile. Below that is a small circular antenna which emits an I band uplink capture beam to gather the missile shortly after launch. The final antennas in the array are two small white rectangular ones, one on either side of the array mounted alongside the I band. These are used for command uplink to the missile. This twin antenna system permits the 'Land Roll' radar to control up to two missiles simultaneously against a single target. The two missiles can be guided on different frequencies to further complicate electronic countermeasures (ECM). There is a tubular device fitted to and above the tracking radar; this is a 9Sh33 electro-optical tracker. It can be used to track the target when the main tracking radar is jammed by ECM. A 9K33 battery comprises four 9A33B TELAR