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well it would be kinda difficult to control a remote-controlled drone if it's completely radio silent.
by forgotmysn 9y ago
well it would be kinda difficult to control a remote-controlled drone if it's completely radio silent.
- eps 9y agoDJIs can fly along a programmed path.
- forgotmysn 9y agotrue, touche.
- baddox 9y agoGPS signals are radio waves, but they are read-only.
- leggomylibro 9y agoTell that to the truckers who accidentally cause panic in a metropolitan area when they forget to turn off the jammer they use for fudging hours and miles. Those signals are very weak by the time they get down here, and easy to override. It's just illegal.
- deleted 9y ago[deleted]
- Nexxxeh 9y agoI wonder what level of accuracy they could manage with dead reckoning?
- serf 9y agoif you're thinking about how to get a drone to determine its' place in space without radio make sure to consider celestial navigation.[0] The SR-71 Blackbird used a navigation system that incorporated both methods (inertia and star-watching).[1] [0]: https://en.wikipedia.org/wiki/Celestial_navigation https://en.wikipedia.org/wiki/Celestial_navigation [1]: https://timeandnavigation.si.edu/multimedia-asset/nortronics-nas-14v2-astroinertial-navigation-system https://timeandnavigation.si.edu/multimedia-asset/nortronics...
- ethbro 9y agoI remember we had a star tracking device come to us via some donation source for a prototype satellite build when I was in college. About as big as my fist, from memory. Unfortunately, it was Russian and the only documentation accompanying it was one page, in Russian. But there are certainly CotS parts that you can buy to provide a star-tracked location data source.
- njharman 9y agoUnless there is no wind at all, pretty poor.
- aw3c2 9y agoEven then, sensor drift is a huge problem.
- milankragujevic 9y agoCouldn't it use a camera pointed towards the ground and track objects on the ground to measure absolute movement in space? Like Parrot's drones do. Probably DJI drones as well, since they have ground-facing camera(s).
- pjc50 9y agoSure, although it would then be misleading to describe it as "dead reckoning" when it's actually some kind of SLAM system.
- fest 9y agoWith MEMS based gyros and accelerometers: not enough to maintain position. With much larger and more expensive gyros/accelerometers dead reckoning is enough to navigate without external navigation systems for at least a few hours.
- jrockway 9y agohttps://en.wikipedia.org/wiki/Inertial_navigation_system https://en.wikipedia.org/wiki/Inertial_navigation_system
- dsfyu404ed 9y agoEarly ICBMs used inertial guidance systems. Some cruise missiles use terrain maps. With enough funding it shouldn't be a problem to get gps level accuracy with modern technology.
- notatoad 9y agoOh? https://www.newscientist.com/article/2143499-ships-fooled-in-gps-spoofing-attack-suggest-russian-cyberweapon/ https://www.newscientist.com/article/2143499-ships-fooled-in...
- baddox 9y agoOf course, for the drone, I meant.
- tlrobinson 9y agoWhy aren't GPS signals signed?
- 05 9y ago* Actual information is derived from phase shift between signals, not their contents * Signals are below noise level, you need to know their exact contents to be able to receive them * Military modification is encrypted, and it can help against some sorts of spoofing. * To spoof, you need to - receive signals from at least 4 sats (e.g. using a 2d phased array you can get pretty good directional sensitivity without knowing the contents of the signal). - retransmit the signals to the target, time-shifting each signal to achieve the required time+coordinate spoofing delta. - jam the original signals with a known noise source you can subtract from your own received signal to avoid jamming yourself ;)
- pjc50 9y agoThere used to be a separate encrypted channel for military use ("selective availability"). There's a replacement, secret system which is supposed to provide the same anti-spoofing for NATO military uses only. The data rate of GPS is surprisingly low. Furthermore, you can spoof someone's position by relaying genuine signals provided you alter their relative time delay.
- scrps 9y agoI don't know if the secret service is using a modified DJI or their own in-house design but they were testing a non-RF teathered drone: https://www.dhs.gov/publication/dhsussspia-020-united-states-secret-service-counter-surveillance-division-unmanned https://www.dhs.gov/publication/dhsussspia-020-united-states...