[HN Gopher] The race to find GPS alternatives
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       The race to find GPS alternatives
        
       Author : Brajeshwar
       Score  : 19 points
       Date   : 2025-06-08 16:21 UTC (6 hours ago)
        
 (HTM) web link (www.technologyreview.com)
 (TXT) w3m dump (www.technologyreview.com)
        
       | infocollector wrote:
       | The problem I see with investing in such technologies:
       | 1. Satellites are too far to fight anything on ground (Power per
       | unit area (i.e., intensity) decreases as the square of the
       | distance)       2. If the Satellites are relaying to things on
       | the ground, they are also relaying their location (easy
       | adversarial targets)       3. In a war (they mention Ukraine in
       | the article), first thing that is toast is these satellites.
       | 
       | I don't think this is the right replacement for GPS. Perhaps
       | someone here can correct me if I am wrong?
        
         | dieselerator wrote:
         | > I don't think this is the right replacement for GPS. Perhaps
         | someone here can correct me if I am wrong?
         | 
         | Though I do not agree with your reasons, I do think this Xona
         | is not the right replacement for GPS.
        
       | SoftTalker wrote:
       | How good are accelerometers these days? With a known starting
       | point, map data, a good clock, and accelerometers you should be
       | able to compute your position using dead reckoning.
        
         | monster_truck wrote:
         | Anything that works well enough to do this usefully & reliably
         | is export controlled for obvious reasons
        
         | userbinator wrote:
         | https://en.wikipedia.org/wiki/Inertial_navigation_system#Dri...
         | not that great although they've been in use for many decades.
        
       | asdefghyk wrote:
       | How did ships navigate 200 years ago? Not sure how accurate it
       | was ?
       | 
       | How about using the stars? ... only at night ?
       | 
       | Use triangulation to known RF transmissions ( ie like direction
       | finding of RF signals )
       | 
       | Geography recognition , rivers mountain's . towns etc ( Lidar ? )
       | 
       | Broadcast this info on some other secret frequency - drones only
       | need to listen to the info
       | 
       | Use radar to track drone and broadcast its position to the item
       | ...
        
         | mshook wrote:
         | The B-52 and SR-71 had star tracking systems for that exact
         | reason. Not sure about the B-52 version but the SR-71 worked in
         | daylight.
         | 
         | https://www.glennsmuseum.com/items/b52_astro/
         | 
         | https://theaviationgeekclub-com.cdn.ampproject.org/v/s/theav...
        
           | sroussey wrote:
           | I wonder how satellites affect that now. So many more by an
           | orders of magnitude
        
       | politelemon wrote:
       | Question please, it says that jamming these is more difficult.
       | But doesn't that mean it's not impossible, so at some point in
       | the future it could happen?
        
       | AlotOfReading wrote:
       | I really don't understand the founding motivation for this
       | company. For one, autonomous vehicles (e.g. Waymo) don't use GNSS
       | as the primary means of localization. You can also achieve
       | centimeter (and higher) precision with RTK. The main source of
       | errors is usually reflections, which are still a problem here. A
       | higher SNR helps, but I'm not sure it helps _enough_ to justify
       | the endeavor.
        
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       (page generated 2025-06-08 23:01 UTC)