The 3D pulse Doppler electronically beam steered E/F-band surveillance radar provides range, azimuth, elevation and automatic threat evaluation data on up to 48 targets for the digital fire control computer processing system. Automatic track initiation can be performed on the 10 most dangerous targets, which are categorized and prioritized in order of threat for engagement. The operator reconfirms the highest priority target choice and tracks this target before firing the missile. The maximum radar range is stated as 25 kilometers, but the rapid five to eight second reaction time [including fire control target prioritization] suggests a somewhat greater range. The radar antenna, on top of the turret, is swung through 90º to the horizontal position for travel. Target radar surveillance is carried out on the move but the vehicle would normally come to a halt for missile launch.

https://www.globalsecurity.org/military/world/russia/sa-15.htm