Inertial guidance is simply employed to allow a missile to reach a specific, precomputed point in the space before terminal homing.
OK. Lets pretend you are right.
A target behind my aircraft has his radar on and based on that signal I can get a precise angular lock on his aircraft, so I launch my R-73 and it uses its thrust vectoring capability to pull a 180 degree turn off the rail.
With no data link the missile is now facing towards the target, but how does it identify the target?
When engaging targets in front of the aircraft the radar or IRST or helmet mounted sight is used to turn the actual seeker in the missile directly at the target so it is in the centre of view for a lock... after pulling a 180 degree turn the R-73 will be moving backwards in relation to the launch aircraft but the turn will have offset its position 100m or more depending on the flight speed of the aircraft, it is now looking back but there is no datalink for the launch aircraft to see what the missile can now see or vice versa.
What happens when it does its 180 degree turn and sees 4 aircraft... the 100m offset means the missile will be seeing those 4 aircraft from a different perspective from what the rear facing sensors on the launch aircraft saw them and are still seeing them.
What if the missile selects the closest threat... what if the closest threat is your wingman?
If it were possible to fire at targets unseen behind the aircraft then the R-73 would be a much more capable missile... you could fire it toward radar contacts and as it gets closer it will get a lock and guide to the target.
Without a datalink however it could just as easily lock on to anything in its field of view of course.
BTW you make it sound more sophisticated than it is, inertial navigation for a V-1 is to fly in a specific direction (by physically angling the launch ramp in the correct direction) for a fixed period of time and then cut the control surfaces lines to make the weapon fall from the sky. R-73s can be carried by all manner of aircraft, many of which have no radar or means of determining range to targets, like the Yak-130 with no radar, but with a helmet mounted sight you can get a visual lock which is good enough for such a missile as its range means it is a WVR missile and if you can see it, it can probably reach it.
Firing an R-73 from a Ka-50 means the R-73 will be launched with no idea how far away the target is, it will just fly at the locked target till it runs out of fuel or impacts the target. It will certainly not create a 3D model of the space around it and calculate an intercept point to fly to.
That is pointless for an IR guided missile.
For an ARH missile it is crucial as the inertial nav system has to get the missile to a point where the target is in range of the missiles radar seeker... too close and the missile might not get a lock before it blows past, too far away and it might not get a lock either and it will give early warning of the attack.
The difference of course is that ARH have datalinks and more accurate target data from the launch aircraft that will be updated during the missiles flight.
In no way at world a 5,8 kg MK-80 seeker of an R-73 was capable to track a target of any type at..... 30 km , head-on !!
An SR-71 has a surface temperature of over 350 degrees at normal operational height and speed.
Modern seekers don't rely on detecting very hot things... that would make flares too interesting.
I am also referring to high altitude use, where the ambient temperature is -62 degrees C or colder and there is no earth clutter to distract the missile.
At high altitudes there is little moisture to reduce range and no weather to interfere. Remember we are talking about MAX range too, not normal or expected range.
GarryB you are an intelligent person ,please stop one moment and reason, i understand that you attempt to "adapt" Gordon's words to your idea...but believe me it is simply impossible ; there is no way at world for a R-73 making an U turn after launch against a pursuing aircraft to have the target in the field of view of its seeker before having complted the 180 degree turn, for this reason that Yefim Gordon specify that the aircraft must have a tail protection system enabling targeting in the rear hemisphere.
Mindstorm, you are an intelligent person, please stop one moment and think, even with a rear facing sensor like an IRST that could pass on to the missile an IR view of the target to get something to compare with when it turns and looks for itself no aircraft are fitted with rear facing IRSTs, there are no datalinks connecting the launch aircraft with the missile so it can be given live data of the target when it starts looking.
The rear facing sensor system is for missiles launched rearward and it is used in exactly the same way that the forward facing sensor systems are used with the R-73.
They find the target and give angular information for the missile seeker to look directly at the target and get a lock before the missile is launched.
Rear facing sensors would not work with a forward facing missile for the same reasons that a rear facing sensor would be of no use with forward facing missiles.
Before the missile is launched the seeker needs to be locked on to the target.
There is no ability to acquire a new target after launch... otherwise your own wingmen are in serious danger.
Take into account that also the claimed times of development and introduction ,range of engagement ,field of view of the seeker etc..etc... correspond perfectly to those of izdeliye 760 ),therefore is perfectly possible that Russian internal version of the missile has the few izdeliye 760's features lacking in the export version
If the domestic IR AAM had lock on after launch capability then there would be little reason for the new missile, and certainly much less urgency.