Now that is more like a mast mounted optical sight... note no lens covers because instead of a separate lens cover mechanism it would normally be turned down to view directly down which would cover the lenses and protect them from dust and damage without needing an extra separate mechanism.
Optical sensors on top and that box appears to be a battlefield radar which could scan for targets in extreme weather day or night.
BTW the 120mm mortar is an interesting beast... the new ones are breach loaded because of the length of the barrel making muzzle loading impractical.
Can't say I have seen a towed breach loading 120mm mortar being operated in the field... most often it is a muzzle loaded weapon.
That mine probably replaces the TM-83 roadside mine, which is normally placed by the side of a road or track and it attacks the side armour of vehicles.
Obviously attacking the top armour is rather more efficient...