alt Hacker NewsPerhaps 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?
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EDIT - from the paper, this is incorrect,
> The introduction of GPS caused the interest in celestial navigation to wither due to its relative inaccuracy. Consequently, celestial navigation is primarily seen only in space-based systems, whose orientation must be known to high levels of precision. Nonetheless, celestial navigation was identified as a desirable alternative to GPS [2], primarily due its robustness against potential jamming. Critically, few GPS-denied alternatives exist that are capable of using passive sensors to estimate global position at night or over the ocean. For this reason, celestial navigation remains an important topic of research.
The US and other militaries never stopped using these systems. They just stopped talking about them as much. Here's a literature search showing some of the slow & steady research on the topic,
https://scholar.google.com/scholar?q=astro-inertial+navigati...
Example systems that have been deployed in many (most? all???) American combat aircraft,
https://theaviationist.com/2021/09/10/lets-have-another-look...
https://www.gpsworld.com/honeywell-demonstrates-military-gra...
https://ieeexplore.ieee.org/document/290940
Alright. I'm ready to be on that list, Mr NSA agent.
Replies
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.
You're definitely on the list of people worried about being on lists now.
I've also been told learning too much about linux or the nuclear reactions in power plants or bombs puts you on a list. I just assume I'm on several.
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 the published code, and definitely not fix any of the bugs it had.
So, yeah, you're not wrong.
There are nuances to the rules, involving things that're openly published online, but I don't understand it in the least. A hacker's guide to ITAR would be an interesting document indeed.
Not NSA - you'd have someone from US Bureau of Industry and Security tracking you down (no pun) for most likely violating export controls if you were to openly share information on building the technology.
Celestial tracking is a dual use technology (See 7A004 or 7A104) - https://www.bis.doc.gov/index.php/documents/regulations-docs...
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.
Plenty of homework assignments in graduate level aerospace engineering courses that are right up the alley of this paper. Star trackers as backup for GNSS would be of great interest to maritime vessels worried about spoofing. So there are plenty of non-military use cases for these algorithms.
These days celestial navigation is trivial. See my comment here
I'm told quantum navigation is the new hotness for being on lists these days
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 searching my house. Certainly on a list now :(