Do not confuse three pairs of notions:
- piracy and espionage;
- Almaz's copyright with any country's national security (dependant upon many things, software simulators being rather close to the end of such list);
- and finally, better and worse jokes
. Should it be legal to get it without being a S-300 user, it would be already offered for sale at Almaz's website. Everybody likes making money.
I'm confident about the future, when S-300 finally gets an Excess Defence Article status, but - will we be still alive until then?
About TVM (using layperson-to-layperson method - Hpasp, please react decisively for any blasphemy):
first, about two guidance systems we already use in SAMSIM:
1) pure command guidance: missile absolutely 'dumb', flies where fire control radar directs it to do so (Wolkhov, Neva, Krug). In order to do so, radar should accurately see when the target and missile is.
2) semi-active radar homing, when missile knows accurately just direction of the target (not distance), homing on reflected radar signal (not own, but fire control radar's - that's how Vega works). Radar does not need neither to see accurately the target nor the missile position - just keep the beam on the target, fire when in range (plus-minus hundreds of meters), and missile will find its way. Better than method 1, but the missile still can react in its only one fixed way (guidance method, e.g. half-lead) for target maneuvers. Generally works well, but... (see: target maneuvers)
Track-via-Missile combines advantages of two guidance systems. Imagine a missile having a good "nose" (semi-active radar seeker) but otherwise dumb, and under constant oversight from a ground-based "brain" (fire control radar) that tracks target and missile at the same time and can direct the missile to better react for target's behaviour. Furthermore, the missile can transmit what it "sees" (target position in angle versus missile) back to the radar - and ta-daaa, we have target info from two sources!