Interesting that ships turning off their AIS transponders can still be picked up from their radio or naval radar signals from orbit.
It seemed a bit extreme that the single satellite RF detection and localization technique referenced in the article would get classified by the U.S. government -- it's presumably a beamformed angle & doppler measurement going into a detection algorithm which is aware of the motion of the satellite platform, which is cute but not groundbreaking -- but at the same time it's probably a very inexpensive technology for space-based surveillance of RF emitters, which has obvious national security ramifications.
It seemed a bit extreme that the single satellite RF detection and localization technique referenced in the article would get classified by the U.S. government -- it's presumably a beamformed angle & doppler measurement going into a detection algorithm which is aware of the motion of the satellite platform, which is cute but not groundbreaking -- but at the same time it's probably a very inexpensive technology for space-based surveillance of RF emitters, which has obvious national security ramifications.
smallsat = cheap
cheap = affordable for smaller nation states
RF emitters = many military assets