If it receives a cm wavelength jamming, it is constantly measuring the targets elevation angle.
Assuming that the target is not changing its altitude, similarly as the Volhov's I87V method, the target range can be continuously calculated depending its measured elevation.

It measures target elevation angle but how it knows about range and altitude?
Example - I started in Asuluk and used simulated F-104 with cm jamming - I started to track it as jamming target (without use of 1S12M1) and I saw on Three Dimensional Indicator (Angle Officer’s K81-5A panel) dot of target position - correct one. Thus I don't need to manually input range (or altitude) data as is written in manual on page 48, point 9 - in fact I never need to use this.

If I use S-75 or S-125 I can not determine range (or altitude) without external input (board, P-15/18) but KRUG seems to be able to determine right range and altitude of jamming target automatically.

May be it is that way, I just want to understand.