They already exist.
http://en.wikipedia.org/wiki/XM395_Precision_Guided_Mortar_Munition
It is a two part system.
One part is a laser that has a specific frequency and has a coded pulse built into the beam.
A soldier equipped with this laser acquires a target and centres it in the sights.
He then radios the mortar team who fire a round in the general direction of the enemy.
When the round reaches its apogee the soldier with the designator activates the laser (this is known as lasing even though to lase is not a verb. a laser is not something that lases it is an acronym for Light Amplification by the Stimulated Emission of Radiation).
The Mortar round looks down, "sees" the point of reflected laser light and guides itself onto the light.
BOOM!
Laser guided mortar.
Currently it is only available in 120mm but in the future the technology will allow this to be made smaller.
Interestingly there are also heat seeking mortar rounds that reach apogee and then "look" for hot things and guide themselves down onto the heat source passively.
I suppose the game mechanic for that would be as follows:
1. Select heat seeker.
2. Fire as normal.
3. Do not scatter.
4. Roll
2d6.
5. Identify all valid targets in the
2d6 radius.
Valid targets include anything hot:
Vehicles.
Wrecked vehicles.
Units that have been attacked with flamers/melta/plasma weapons this turn.
Units that have fired flamers/melta weapons this turn.
Units that contain a Plasma gun that has "got hot" that turn (how much would that suck? Your gun blows up in your hand, you somehow survive and then a mortar lands right in your lap. Brilliant.
The Eldar Avatar
Probably more I can't think about.
6. Randomly select one of the valid targets.
7. Hit it, no cover saves.
Is quite clever actually, not too overpowered and if the
2d6 roll is a large number you could hit targets that are already dead or your own guys.
There are also GPS rounds.
Of course they rely on on the Global Positioning Satellite system which the planets of the empire do not have.
However, if you allow that ships in orbit can create a similar effect or that the empire has an equivalent system then you could include them in play too.
To use GPS rounds you need a super accurate reading for the position you want to hit.
You can do that two ways.
1. Gather the data before the battle, this fits in with the "pre-arranged fire zones" rules.
2. Triangulate the position on the fly.
For that you need two minis equipped with accurate GPS positioning equipment and radios (forward controllers).
They both give range and bearing to target (using
bs, cover saves apply, armour saves do not) and then calculate the position of the target.
If one of the forward controllers fails to "hit" the target then you cannot fire the mortar at all.
Mortar fires and hits with no cover save, armour saves do apply.
Can't target anything going faster than 6" a turn.
Had another idea for mortars too that is mentioned above.
Forward controllers:
Expensive characters, part of the
HQ like tech priests and are embedded into units, can be independent and have stealth but probably not a good idea.
Must target the same thing as the unit.
Equipped with a voxcaster and 1
ccw.
During play can "control" any ordinance weapon or mortar that also has a voxcaster.
Gives 2 advantages:
1. Can use "bracketing fire" rules on targets moving at up to 6" per turn.
2. when controlling barrage weapons the first template is placed as normal with the scatter dice but the subsequent barrage templates can be placed by the player in any position that touches an existing template.
Yes. You can "walk" fire onto a target you have missed with the scatter dice.
Might be too powerful though.
What do we think?