I see many people are curious about BUK operations without auxiliary radar(and command) vehicle so here it is how it operates autonomously, copied from russiadefence.net forum :
"You have to know few things about Buk. TELAR with missiles have only tracking radar and TV camera for back up. Crew in TELAR could recognize target only through TV camera and if sky was in clouds, that they could not make an ID of the target. Target ID with radar IFF and ID numbers for civil flight could be done through search radar, which for Buk is in special vehicle. Tracking radar doesn't make any ID of target. It only show the object in the air, which it lock. You could not distinguish in tracking radar, if it is civil plane, military plane, helicopter, missile, drone, etc. In the video you could see tracking radar scope picture at 6:44.
https://www.youtube.com/watch?v=8X8dvKtBAQk
It is tracking radar scope picture from OSA, but in Buk from the eighties, radar scope picture is no different than in Osa or in other SAMs from that time. Actually even today are similar, only screens are more modern.
When you work in radar mode and your tracking radar lock the target and you launch the missile, than the system works automatically with radar and computer and operator could only watch the screen. Operator have to work with tracking radar only in case of ECM.
So, if sky was cloudy and Ukrainian Sukhoi escape in the cloud, than operator in Buk TELAR could only search and lock with tracking radar, where all objects in the sky are seen as a hill on the line. So without visual ID with TV camera he could not know, what he locked. Ukrainian Buk batteries have all components with battery command posts and search radars, so they have situation awareness picture from CP and they could know, which target is which without visual ID with TV camera."