Let start from the basis : Lock On Before Launch mean simply that all the necessary vectorial data for generate an useful intercept point must be present for the sensor suit (and not specifically missile seeker...except,as i will further explained successively down here,for very short range combat employing HMS ) before weapon delivery , without chances to update those data in-flight, change initial point of intercept designated toward a target on which you obtain a lock after missile's delivery or capability of the missile to self classify or designate a "target of opportunity" in an area, etc..etc...
Excluding radar guided missiles as he has by talking about the R-73E and RVV-MD, which are both IR guided missiles, lock on before launch in this case means that before the missile can be launched it must have a solid lock on the target.
It does not need to calculate anything, it just needs a sensor on board the aircraft to direct the seeker in the missile to the target. That sensor can be the helmet mounted sight, the IRST, or the radar. Once directed to the target and a lock is achieved meaning the seeker is now tracking that target exclusively, then the missile can be fired.
A lock on before launch missile cannot be fired to fly to a specific place in space and then find and lock the target itself... that would be lock on after launch.
There is no datalink for communication between launch aircraft and either missile mentioned, so a missile launched without a lock will hit only the ground.
R-73/73M1/M2 in particular are missile with a inertial mid-course proportional guidance up to a preselected point of intercept and terminal IR guidance.
Perfectly true, but we are no longer talking about LOBL or LOAL, we are talking about the flight control algorithm that controls the flight surfaces of the missile and "flys" it to the target. Older model missiles will point their noses at the target and fly straight at them till they hit them due to their superior speed. Very simple, but offers the pilot more options to out fly the missile as it is flying to where he is and usually ends up in a tail chase to hit the rear of the tail pipe.
Proportional guidance means the missile determines the rate at which the target is moving within its field of view... if it remains stationary then the target is either moving directly towards or away from the missile and it will continue to fly till it hits the target on that course. If the target is moving in its field of view it corrects its flight... it is not so sophisticated as to calculate an intercept point in 3D space and time... it has no range information for closing rates so it cannot perform such a calculation. It determines the rate at which the target moves and instead of flying directly at the target by turning a little, it turns a lot more till the target stops moving in its field of view.
This means the missile is no longer flying directly towards the target but at an angle ahead of where it is moving so that the target no longer moves in its field of view... this means that after a period of time the missile will either run out of fuel and energy and fall to the ground, or it will hit the target.
Think of it in terms of people on the ground. One person is walking a course that is not straight from one end of a room to another. If someone else representing a missile starts to approach from the side and walks twice as fast as the target and keeps heading towards the target because the target is moving the missile will always be heading to slightly to the rear of the target, but because it is moving so much faster it will always hit it... and for shots from behind or the side it will most likely hit the target in the rear.
Now change the "guidance rules" for the missile. As it moves towards the target (which is not walking in a straight line remember) it will turn until the target stops moving... from the side that means walking toward a place slightly ahead of the target that will exactly coincide with where the target will be when you get there. When the target turns (because it is not walking straight) it will start moving again in the missiles field of view and so the missile will need to change course so that the target will be stationary in its FOV again.
For the target to be stationary in your field of view while it is moving and you are moving 2-3 times faster than it is that means you are getting closer and will impact the target unless it changes course and you do not. If it changes course and you correct your course then you should hit... assuming no countermeasures of course... we are talking about the guidance not the ECCM.
Talking of the last capability named in the Jane's article (capability to perform a 180 degrees turn after launch ) it is mentioned also by Yefim Gordon in its "Soviet-Russian Aircraft Weapons since World War Two" ,pag 33
That means that a target flying directly towards the launch aircraft, but offset to the side by a distance, you can get a lock, fire a missile, and it will use its thrust vectoring to pull a high g turn to keep the seeker nose pointed at the target as it flys past the launch aircraft and heads back behind the launch platform. The missile has turned 180 degrees to follow the target but it needs to keep its seeker pointed at the target at all times to have a chance of hitting it.
A missile with lock after launch capability can be fired forward at a target already behind the launch aircraft and it will perform the same 180 degree turn and then it will look for and ID the target before getting a lock and intercepting it.
The thrust vector capability of the R-73 allows it to be mounted on a weapons pylon facing backwards, so you can get a lock on a target behind the aircraft and fire the missile at a target behind the aircraft... it needs that thrust vectoring capability to keep the seeker in the nose pointed at the target throughout the engagement.
R-27s were tried but as their forward speed changed from negative to positive... ie they were hanging there at zero forward speed, without thrust vectoring the main butterfly wings stalled and the nose dropped and the missile lost lock of the target.
The HMS works solely with IR-Homing missile. Using it the pilot is able to fire a missile quickly at an enemy aircraft within visual range when sorely pressed for time during a dofg fight.
The helmet sight and missile combination are ideal... in a western fighter the pilot tries to turn their whole aircraft to point the nose at the target, which also points the missiles on the pylons at the target and then activates the missile seeker to try to get a lock, or scans with radar and then directs the missile seeker to look where the radar is tracking to get a lock.
With the Mig-29 or Su-27 the pilot lowers a small monacle that has a cross hair on it. The pilot turns his head and looks at the target aircraft (which is a threat so of course he wants to visually track the enemy aircraft as much as possible anyway) When the target is within the 90 degree field of view of the R-73E he can push a button on his control stick to get the seeker of the selected missile to look where he is looking (determined by a system that tracks his helmet) and when it gets a lock the cross hair starts blinking... he is now free to pull the trigger and launch the missile.
With thrust vectoring capability the missile can pull very hard turns off the rail... just like the Mig-29OVT and point its nose in any direction it wants in flight.