Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Celestial Navigation for Drones

mdpi.com

Post reply on HN
Print view View original

21–30 of 130 posts

Re: Celestial Navigation for Drones

#21

Post by biofox »

7thpower wrote: post #19
biofox wrote: post #10

Earlier quoted context omitted.

You will likely raise a flag somewhere if you publicise what you are doing, but I highly doubt there would be any issues if you're working on this in private as a hobby. As for chemicals, I can personally vouch that it is a terrible idea to order reagents (or even chemistry equipment) as an individual. I tried to teach myself organic synthesis in the summer before starting my doctoral studies, and ended up with MIB s…

Please tell me there is a blog post or something documenting this experience. Sounds like a fun read.

Afraid not. I don't have much of an online presence, so didn't think to write anything.

Re: Celestial Navigation for Drones

#22

Post by avs733 »

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…

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 mountains basically got to tall to fast to give the crew sufficient time to react because of that system. That caused Honeyweell to go back and look at ways to improve the system to be predictive rather than reactive - using a terrain database.

Honeywell bought/came into posession of a russian world wide terrain altitude database to do the first generation of this. I can only imagine the US had the same thing, or more accurate, but this was far enough ago that US Government wasn't sharing.

Re: Celestial Navigation for Drones

#23

Post by areoform »

avs733 wrote: post #22
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…

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...

Re: Celestial Navigation for Drones

#24

Post by imglorp »

boscillator wrote: post #11
plasticchris wrote: post #3

Earlier quoted context omitted.

Or in short, the sensors are strapped down to the platform being measured - like your phone’s sensors for example.

Yes! It's in contrast to gimbaled systems. Putting the measuring instrument on a gimbal simplifies the math and often improves accuracy, but at the expense that you need this large moving object that needs more power.

Gyros on gimbals have other drawbacks, such as drifting and gimbal lock.

Re: Celestial Navigation for Drones

#25

Post by hnthrow90348765 »

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 told quantum navigation is the new hotness for being on lists these days

Re: Celestial Navigation for Drones

#28

Post by jcims »

mapt wrote: post #17
maxglute wrote: post #12

Ctrl+F and 0 results for munitions or bombs. Seems like this is really about $25 controller gets drones to within 4km in GPS denied enviroments, after which a $50 infrared camera + DSMAC find targets to hit.

Thanks for the summary. I suspect you could get this to FAR higher accuracy if you combined it with a recent upload of Starlink et al LEO constellation ephemera, an initial GPS fix at launch, and a planned flight path, because LEO constellations are bright foreground objects (high location-specific parallax differences against background stars) at apparent magnitude of about 5.0. This is simultaneously not reliant on…

That's a great idea. In the earlier days when they had about 2500 satellites in LEO I built a small visualizer from the fleet TLE data and it was remarkably simple with the skyfield library.

If you're in the fringes of a GNSS denial area ADSB might be useful as well. Would need more hardware of course.

Re: Celestial Navigation for Drones

#29

Post by alexpotato »

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).

Re: Celestial Navigation for Drones

#30

Post by notahacker »

myself248 wrote: post #15
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…

Years ago, an acquaintance developed an autonomous flight controller for "real" helicopters. Cyclic-collective-tailrotor types. It would work on a full-size cargo helo just as well as an R/C model. He released it online, because why not? Drones are cool. Some very nice gentlemen showed up and explained that he couldn't do that. He didn't get in any actual trouble that I'm aware of, but they "asked" him to take down t…

> A hacker's guide to ITAR would be an interesting document indeed.

I suspect producing something called "a hacker's guide to ITAR" really would get you put on a list...

Post reply on HN