from 1:01 they showed the IRST, and what can we understand from that image?
There is a "thing" over there. Karat can see and track it, determine the elevation angle and direction (azimuth) of the "thing", precisely. Some blurred numbers at that screen should include it.
Also, before and after the 1:01, we see some little manuevers. I am not sure they show these manuevres because of this, but Karat can determine the distance from the thing by slightly changes its course or moves to observe it from different angles. The computer "estimates" the distance by performing trigonometric calculations based on the angular rate of change of the thing. Not precisely this time, but approximately, even statistically (I just oversimplified, it is not that simple of course, there are some additional variables about this process) . So there should be some information about it in blurred areas also.
These are my points. We have people here who have much more knowledge about it. If they share their views, I could sure use it, too.