I'll be glad if someone explains how this things work...
KRUG and Vega uses the monopulse method of target tracking.
Instead of mechanically scanning the target like the Dvina/Volhov/Neva...
... they emit only one impulse in a pencil beam. (blue)
They receive the reflected signal with three physically displaced antenna. (red/green/blue)
With simple math, the target precise position can be calculated.
- red antenna received signal phase equals the target delta horizontal direction from the boresight.
- green antenna received signal phase equals the target delta vertical direction from the boresight.
- blue antenna received signal phase equals the target delta direction from the boresight.
am I confusing?
What you see here are the physically displaced receiver helix antennas.
They receive the incoming impulse (from the SAM), and by calculating the phase difference of the received signal, and knowing the distance of the helixes, they can accurately measure the impulse emitter direction from only one received signal.
Then the head tracking mechanics tries to set the tracking head at a direction, where the received signal phase is the same.