Are you very nautical Austin?
There is an optical system invented by a Brit many many decades ago where lights are reflected off a mirror at the back of an aircraft carrier.
It has three colours... lets say orange, green, and red. The Orange light is angled so it is above the ideal flight path to land a plane on the carrier deck, the green light is reflected at the perfect landing angle and red below that so if you see orange you are too high, green you are on the perfect landing flight profile and if you see red if you don't pull up you will hit the deck hard and crash.
It is the same for Kornet, except the beam has four components or more. Top left, top right, bottom left, bottom right.
In the old Kornet you manually followed the target by turning some handles, but in the new system Kornet-EM it uses a computer to automatically follow a moving target or to stay on a stationary one (if the vehicle you are launching the missile from is moving... like a BMP-2).
The beam is wide all the way... and that is a good thing.
A focussed narrow beam would mean that if the missile strays outside the beam while chasing a fast moving target there would be no way to get the missile back into the beam... remember the auto tracker is following the target... like the first model it does not track the missile.
The missile itself does all the flying... it looks back at the launcher and detects its position within the beam... it can tell how far it is from the centre of the beam by the frequency of the beam it sees and can work out where to fly to get into the centre of the beam. The laser does not transmit course corrections to the missile because it does not track the missile.
How does the operator obtain the range to the target , I would assume the beam is pointing at the target and the reflection from the target from the tripod device is used to calculate the range to the target ?
I would assume it uses a laser range finder.
So in a scenario when the operator has to use the beam just above the target which might just be thin air then how does operator obtain range to target ?
The operator would lase the target to get the range first, or to be sneaky they could simply look for something beside the target to get a range.
The precise range to the target is not critical. Unless it is out of range of the missile the distance to the target is not hugely important except if you want to offset the laser during the engagement. If it is an automatic function of the system then lasing the target or something next to the target that is a similar distance could be used to calculate flight time of the missile to the target and therefore the period of time to offset the beam from the target and of course also the distance to offset the beam during the engagement.
How does Top Attack works for new Kornet-EM , similar to Bill ATGM ?
Kornet-EM has no top attack capability AFAIK.
The offset laser option is to reduce warning time for the target of the attack in progress.
When the beam is dropped back on target the missile will likely hit the target at a steeper angle than if it just followed a direct beam to impact, but the impact angle will still be less than 45 degrees.
BILL2 overflys the target tank with a downward facing HEAT warhead designed to fire from a distance with a magnetic fuse that detects the large metal object that is a tank that aims down at the centre of mass as it flys over head.
Finally on the issue of Spike-ER , I think it has one advantage you can use to attack target beyond LOS , using video images obtain from target while the missile is flying ,missile like Kornet-EM is limited to LOS which makes beyond LOS targetting impossible.
To be effective however you need to actually be sure there is something there before you fire, otherwise you just wasted a missile.
Dragging a fibre optic cable means Spike is so slow an opponent could be armed with shotguns and actually have a good chance of shooting them down as they fly past on their way to targets.
In many ways Spike is comparable to a UAV with a warhead packed into its nose, except most UAVs have much longer endurance.
Kornet doesn't need beyond LOS capability... that is what HERMES is for... and its 20km range and 1.3km/s initial flight speed means it will get there much faster than spike will.