the premise of this is an alternate style of Radar that has both pros and cons to the existing default Radar station.
with the functionality in mind being a base station of sorts that acts not to dissimilar to the Roboport - a base station that the actual entity will dock to to recharge and Et Cetera.
the actual entity, some sort of flying spy drone. obviously this places it in the later half-ish of the Research tree, as you'll need flight and probably a couple other techs to prerequisite such a technology.
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for functionality, a direct comparison between the vanilla Radar:
vanilla Radar:
- covers a moderate area, effectively permanently removing the fog of war in an area provided has Electricity.
'Spy Drone':
- covers a very large area (3x the total area of the vanilla Radar for example), but only scans in a vicinity around the drone.
meaning that the base station either has a very short Radar range or none at all, and the drone circles around the station, revealing the ground when it's near to the area.
- also means that there is a deadzone between the station and the scanning drone. cannot see things that are extremely far away or very close.
technically scans closer ranges on occasion as the drone returns to the Radar Station to recharge.
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the result of this is an alternative Radar station that can cover a much larger area, but does not keep constant live data on any area in particular. and has a close range weakness.
this keeps reason to consider using both styles, as each compliments each other in different ways. with the vanilla showing what's danger close to your Factory in good detail, and the 'Spy Drone' a sort of early warning system, like having guards patrolling the edge of your territory.
i'm sure we all know what Radar looks like from the information side, but i'll make sure the explanation is crystal clear(hopefully).
Radar
tl;dr: an alternative style Radar Station that scans the area more like true Radar, scanning around and providing a circular stream of data that becomes outdated as it continues to scan - except with a flying drone doing the actual scanning.