[HN Gopher] Aircraft Detection at Planetary Scale
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       Aircraft Detection at Planetary Scale
        
       Author : jjwiseman
       Score  : 23 points
       Date   : 2025-03-24 20:40 UTC (2 hours ago)
        
 (HTM) web link (www.planet.com)
 (TXT) w3m dump (www.planet.com)
        
       | yimby2001 wrote:
       | If you were wondering why the US stopped bothering with long
       | range stealth bombers
        
         | morkalork wrote:
         | Like B21?
        
         | dragonwriter wrote:
         | When, precisely, did the US stop doing that?
        
         | NoMoreNicksLeft wrote:
         | Aren't they just waiting for the active camouflaging technology
         | to catch up? Normally, we think about that as something on the
         | underside of the aircraft so that it appears invisible from the
         | ground... but the same principle could apply to the top side of
         | the aircraft if it ever becomes viable.
        
           | NitpickLawyer wrote:
           | That would only be relevant to commercial-based optical
           | spectrum providers. Gov mils have SAR (Synthetic-aperture
           | radar) capabilities that would render that moot.
        
         | mmooss wrote:
         | The US Air Force has developed, tested, and is now in early
         | production of the B-21, a long-range stealth bomber, one of
         | their most important projects.
        
         | TrackerFF wrote:
         | B-52 is still very much active. As for stealth, B-2.
        
       | baxtr wrote:
       | _> After significant experimentation with many different model
       | architectures, we determined that aircraft  <25m in length or
       | wingspan are too small to be reliably detected in medium
       | resolution imagery, so we elected to focus on aircraft this size
       | or greater._
       | 
       | Build small aircraft.
        
         | tuanx5 wrote:
         | Framed this way, it seems obvious that drones and UAV would
         | arise out of this "evolutionary pressure" on aircraft.
        
         | tehjoker wrote:
         | Of course, if you have more satellites or faster imaging speeds
         | you can use higher resolution images.
        
       | 4ndrewl wrote:
       | TFA doesn't really explain how is this better/cheaper than
       | existing ADSB based technologies, or where one is more
       | appropriate than the other (ie which use cases it's targeting)?
        
         | eastbound wrote:
         | Authentication? ADSB isn't authenticated. Anyone can emit,
         | anyone can spoof, and I probably shouldn't say that over the
         | wire. The FAA said in 2012, when the conf at Defcon was made,
         | that it had its own secret mitigation.
        
           | 4ndrewl wrote:
           | Agree on ADSB, but couldnt you spoof this using paint or 1:1
           | scale cardboard aircraft?
        
         | orbital-decay wrote:
         | Mentioning the military might give you a hint...
        
           | 4ndrewl wrote:
           | I mean, commercial services do filter out mil adsb, but they
           | are out there and available. So the use case is tracking
           | movements of military aircraft?
        
             | traverseda wrote:
             | Not all military planes are going to actually have ADSB,
             | obviously. Also even the unfiltered stream requires an ADSB
             | receiver somewhere.
        
               | 4ndrewl wrote:
               | Yes, that's true, but I'm still struggling to understand
               | the market fit for "where are the military aircraft". You
               | would presume the people who need to know this
               | information (ie those people for whom this is actionable
               | data) already know this to a sufficient degree?
        
               | jgilias wrote:
               | They do. Until people who have this information decide to
               | stop sharing it with you.
        
         | xiii1408 wrote:
         | It's not at all comparable. ADS-B is opt-in: you place an ADS-B
         | out transmitter in your plane and turn it on to transmit your
         | position [1]. You're perfectly free to turn your ADS-B off if
         | you like. It's not even required for most of the US, so some
         | planes may not have it installed (ADS-B out is only required
         | within 30 nautical miles of a Class B airport [big airport],
         | inside Class C airspace [medium-size airport], or in Class A
         | airspace [18,000 ft above sea level]).
         | 
         | Military aircraft don't use ADS-B out a lot of the time. Spy
         | planes are obviously not going to transmit their locations. A
         | civilian plane with an electrical failure might stop
         | transmitting ADS-B out. Being able to identify planes via
         | satellite is a whole separate capability.
         | 
         | [1] In all the planes I've flown, ADS-B is configured to
         | transmit whenever the master electrical switch is turned on,
         | but it can be configured to be turned on and off at will. See
         | this video on a mid-air collision involving an eccentric
         | character who liked to fly with ADS-B out turned off:
         | https://youtu.be/G5y3JiOEnVs?si=rs5gNMurZ9ssUloS. If I recall
         | correctly, he had his ADS-B wired to his nav lights so he could
         | turn it on and off at will.
        
           | 4ndrewl wrote:
           | That video is great, thanks. Though the ML solution doesn't
           | seem to claim to be able to identify individual aircraft,
           | just do daily counts of aircraft at specific airfields. Which
           | I guess works for military aircraft, but I guess if you're a
           | nation state actor you've already got this sort of
           | technology/intelligence?
        
           | closewith wrote:
           | ADS-B is mandatory in many jurisdictions and for all
           | commercial flights basically everywhere. Obviously like any
           | transponder, you can pull the breaker, but turning it off is
           | likely to beer the end of you're commercial piloting career.
        
           | jaybna wrote:
           | From my experience in general aviation, I've never met anyone
           | who intentionally turned off their ADSB. It is generally
           | wired into the transponder, and the bulk of air traffic
           | worldwide happens where a transponder is _practically_
           | required. Yes, it is technically not needed but you can 't
           | get help from ATC, can't fly instruments in the clouds, and
           | you can't fly high.
           | 
           | Sure, it can happen but these are edge cases. Space-based
           | ADSB solves this problem with a fraction of the effort and
           | much better data. Spooks might need this for military stuff,
           | but for the bulk of planes, it doesn't make sense.
        
       | barbazoo wrote:
       | > On the commercial side, understanding how many aircraft landed
       | in a city on a specific day can help predict economic trends
       | 
       | lol, as if you'd use satellite imagery for that and not just
       | (freely) available data on airplane movement.
       | 
       | > assess the impacts of world events - such as the quantity of
       | aircraft present for large sporting or entertainment events
       | 
       | wow, there were a hundred small airplanes in Las Vegas, there
       | must have been an event there, who knew. Everyone knew and it's
       | easily available information.
       | 
       | The application is military. That's the only thing this is good
       | for. It's the only thing their screenshots show. Why not just say
       | that.
        
         | closewith wrote:
         | While I broadly agree, I think the era of general freely
         | available data such as aircraft movements is about to end.
         | We're entering an era of siloes.
        
           | cle wrote:
           | I agree with your conclusion, but I'm really curious to know
           | your reasons & predictions here. Can you elaborate?
        
         | cle wrote:
         | Is there freely available data on commercial & private airplane
         | movement in India, China, and Russia? I'd be very surprised by
         | that.
        
       | patapong wrote:
       | I wonder what it would take to do this for in-flight aircraft?
       | I.e. simultaneously surveying the entire sky and tracking all
       | aircraft in flight? This could allow finding downed aircraft much
       | more quickly. Would a megaconstellation like starlink with
       | cameras suffice?
        
       | amelius wrote:
       | They should look into how this can be combined with established
       | radar-based aircraft tracking techniques, e.g. Kalman filtering.
        
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       (page generated 2025-03-24 23:00 UTC)