Shortfinals:
Approach guidance the crew used is still not clear. Doesn't look like PAR, more like surveillance radar approach, which provides guidance like "slightly left of centreline, turn right two degrees, you should be passing [height]".
I have been landing several times at military airfields in Poland.
(Which is legal for private flights, if approved in advance.)
It was VFR, so I will not comment on precision approaches in marginal weather.
I had the opportunity, due to courtesy of the staff, to visit the tower.
So I will just comment, what I saw, as a disused, but still operational PAR
equivalent. The way of use of it was commented to me by the tower staff.
The system consisted of two round CRT radar screens app. 40 cm diameter,
one for vertical and the other for lateral visualization of the aircraft position.
With colour crayons (markers) the lines were drawn on the glass surface
to represent the approach centreline, glide slope and runway threshold.
(I have no idea, how these lines and system was calibrated.)
The controller in front of those screens was giving the pilot voice commands
to keep him (the blip on the screen) on the lines. If the pilot was
not performing according to orders, ATC was able to give him command to abort.
The full authority and responsibility was on the side of the controller,
the pilot was just obliged to read back the orders and report runway in sight.
This might seem to be very primitive system, which it is, but according to my
CFI, a former fighter pilot, who did lots of such approaches, it worked well.
Similar, simple portable systems were supposed to be used on field grass
landing strips to be use in case of war or any emergency landing.
I have no Idea, if such system was in place in Smoleńsk, but it was
supposed to be standard in all Warsaw Pact countries.
It was probably eighter Russian or licensed RSP (Radiolokator Slepoj Posadki).
(Blind Landing Radar)
I am in no way connected to the military, so I can write here what I have seen,
and, what I suppose, is not classified.
I think military pilots, who know more about the system may be in trouble
if writing more about it on a public forum.