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Celestial Navigation for Drones

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Re: Celestial Navigation for Drones

#31

Post by notahacker »

hnuser123456 wrote: post #16
areoform wrote: post #5

Perhaps I am too paranoid, but I've been told to avoid doing any DIY in this field of study. Apparently, or so I'm told, out of the many, many ways to end up on a list — building a working celestial navigation system can lead to some very inconvenient outcomes. Second, only to ordering large quantities of certain chemicals online. Is this true? ——— EDIT - from the paper, this is incorrect, > The introduction of GPS c…

I'm sure there are thousands of datasets of the night sky, and a camera, gyrometer (to get camera angles), clock, and basic image recognition/pattern matching is all you'd need.

yeah. Celestial navigation is a pretty standard thing to study if you're planning on taking up sailing or learning about satellite positioning. Celestial navigation with drones raises more interesting possibilities, but I don't think defence of key strategic assets against drones relies on the possibility it might be too difficult a problem to solve, and there are commercial solutions in the "drone navigation for GNSS denied environments" space. Don't even think the people that jailbreak consumer drones specifically to remove the geofences that prevent them flying near restricted areas get into trouble, at least not until someone spots them flying at the end of a runway or outside a military base.

Re: Celestial Navigation for Drones

#32

Post by perihelions »

alexpotato wrote: post #29

Fun fact: The SR-71 and U2 planes had automated celestial navigation systems b/c GPS wasn't around when they came out. There a story in the book about Lockheed Martin's Skunk Works where they mention turning on the system while one of the planes was in the hangar and it locked on to a hole in the roof (sun was shining through the hole and system thought it was a start).

And, it's a bit older than that: the SR-71's derived from ICBM targeting systems,

https://en.wikipedia.org/wiki/Missile_guidance#Astro-inertia... ("the latter of which was adapted for the SR-71...")

(Actually the very first one, in that history, was an intercontinental cruise missile—a jet weapon that slightly predated (~1958) rockets powerful enough to cross oceans. ICBM's came a bit later. I'm pretty sure the first generation were pure-analog circuits, but I forgot where I read about that).

Re: Celestial Navigation for Drones

#33

Post by rich_sasha »

adolph wrote: post #4

I wonder if GPS and the like will be used more for their clock features than for position. The emissions celestial bodies are perfect fiducial markers [0,1], but connecting them to position still requires accurate timekeeping [2], as the paper notes: Provided the use of an accurate clock, the results presented in this paper will not degrade over time. 0. https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w...…

I guess timekeeping is relatively easy? These systems would only operate independently for a few hours tops. I would imagine even a standard quartz movement would be accurate enough.

Re: Celestial Navigation for Drones

#34

Post by alexpotato »

perihelions wrote: post #32
alexpotato wrote: post #29

Fun fact: The SR-71 and U2 planes had automated celestial navigation systems b/c GPS wasn't around when they came out. There a story in the book about Lockheed Martin's Skunk Works where they mention turning on the system while one of the planes was in the hangar and it locked on to a hole in the roof (sun was shining through the hole and system thought it was a start).

And, it's a bit older than that: the SR-71's derived from ICBM targeting systems, https://en.wikipedia.org/wiki/Missile_guidance#Astro-inertia... ( "the latter of which was adapted for the SR-71..." ) (Actually the very first one, in that history, was an intercontinental cruise missile —a jet weapon that slightly predated (~1958) rockets powerful enough to cross oceans. ICBM's came a bit later. I'm pretty sure the fi…

Reminds me of the "the distance between the rails of a railway are due to the width of Roman horse drawn carts" story.

Re: Celestial Navigation for Drones

#35

Post by throw0101c »

alexpotato wrote: post #29

Fun fact: The SR-71 and U2 planes had automated celestial navigation systems b/c GPS wasn't around when they came out. There a story in the book about Lockheed Martin's Skunk Works where they mention turning on the system while one of the planes was in the hangar and it locked on to a hole in the roof (sun was shining through the hole and system thought it was a start).

The sensor was sensitive enough that it could detect stars during daylight:

* https://theaviationgeekclub.com/the-sr-71-blackbird-astro-na...

* https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w...

* https://en.wikipedia.org/wiki/Missile_guidance#Astro-inertia...

Re: Celestial Navigation for Drones

#36

Post by mpenet »

KineticLensman wrote: post #6
adolph wrote: post #4

I wonder if GPS and the like will be used more for their clock features than for position. The emissions celestial bodies are perfect fiducial markers [0,1], but connecting them to position still requires accurate timekeeping [2], as the paper notes: Provided the use of an accurate clock, the results presented in this paper will not degrade over time. 0. https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w...…

They are perfect markers only as long as you can see them. Clouds and fog are your enemies here

That. However that works just fine for ICBMs and the like…

The future is more likely to be quantum accelerometers and quantum gyroscopes, as they have no “external dependency”.

Re: Celestial Navigation for Drones

#37

Post by avs733 »

areoform wrote: post #23
avs733 wrote: post #22

Earlier quoted context omitted.

Can't find a source at the moment but cool side anecdote to this...working from memory Honeywell was largely the driving force behind developing terrain avoidance systems for commercial aircraft. Those initial systems worked based on comparing the terrain below to the flight profile of an aircraft using a radar altimeter. There was a CFIT (controlled flight into terrain) accident (I want to say AA in Peru?) where the…

You're right! I actually know about the system you're talking about! The US data was classified and Donald Bateman, the engineer behind this and bought the data post Soviet Union collapse. https://en.wikipedia.org/wiki/C._Donald_Bateman https://www.flightsafetyaustralia.com/2023/05/don-bateman-en...

the amount of random 'stuff' like this that I've accummulated over the years could fill a book that is interesting only to me lol

Thanks for the link!

Re: Celestial Navigation for Drones

#38

Post by gunian »

throw0101c wrote: post #35
alexpotato wrote: post #29

Fun fact: The SR-71 and U2 planes had automated celestial navigation systems b/c GPS wasn't around when they came out. There a story in the book about Lockheed Martin's Skunk Works where they mention turning on the system while one of the planes was in the hangar and it locked on to a hole in the roof (sun was shining through the hole and system thought it was a start).

The sensor was sensitive enough that it could detect stars during daylight: * https://theaviationgeekclub.com/the-sr-71-blackbird-astro-na... * https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w... * https://en.wikipedia.org/wiki/Missile_guidance#Astro-inertia...

That's insanely cool what kind of cameras / telescope are strong enough to do that? My guess is it was primarily hardware and not software bacuse of compute limits

Did the planes have to fly above clouds?

Re: Celestial Navigation for Drones

#39

Post by sho_hn »

alexpotato wrote: post #29

Fun fact: The SR-71 and U2 planes had automated celestial navigation systems b/c GPS wasn't around when they came out. There a story in the book about Lockheed Martin's Skunk Works where they mention turning on the system while one of the planes was in the hangar and it locked on to a hole in the roof (sun was shining through the hole and system thought it was a start).

The excellent CuriousMarc YouTube channel just started a new video series refurbishing a B-52 astrotracker, going over all of this in some detail:

https://www.youtube.com/watch?v=GkEjLqu-JH0&list=PL-_93BVApb...

Recommended.

It also immediately occured to me how much easier this should be on a copter, since you don't need a gimbal'd platform :)

Re: Celestial Navigation for Drones

#40

Post by sho_hn »

gunian wrote: post #38
throw0101c wrote: post #35

Earlier quoted context omitted.

The sensor was sensitive enough that it could detect stars during daylight: * https://theaviationgeekclub.com/the-sr-71-blackbird-astro-na... * https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w... * https://en.wikipedia.org/wiki/Missile_guidance#Astro-inertia...

That's insanely cool what kind of cameras / telescope are strong enough to do that? My guess is it was primarily hardware and not software bacuse of compute limits Did the planes have to fly above clouds?

Check out the CuriousMarc video series I linked under the OP, which gets into the sensor used and the encoding scheme.
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