Passive radar/lidar

[heselbine]

I'm sure this must have been covered before, but...

Surely there's no such thing as passive radar/lidar? Radar/lidar by definition need a transmission source, don't they?

Shouldn't the passive radar/lidar column of the sensors table on p150 of the core rulebook be the same as the EM column?

 

[Sigtrygg]

Passive radar and lidar require a separate transmitter for the radio waves or laser beams, the detectors can be separate systems and on a different vessel.

Since active transmission of radio and laser for sensor purposes makes you much easier to spot, then putting the radio and laser transmitters into smallcraft, drones or even missiles may be a useful tactic...

 

[Old School]

Yes, passive radar is very much a thing. And yes, it is often confused with ESM systems that detect various EM emissions, but they are not the same thing. Passive LIDAR? Not really a thing, as far as I know.

 

[Condottiere]

I guess it depends on source.

Passive would pick up on radiation emissions that are reflected in their direction.

Active would be you creating that source, like a torchlight.