51–60 of 358 posts
How complicated/expensive would it be to build an open source star tracker nowadays? How accurate of a fix could you get just by pointing a phone at a sky? Or a DSLR on a commercial gimbal?
> were highly accurate, able to lock onto up to 11 stars (even in daytime) and resolve the craft's position to less than 300 feet (91 m)
ICBMs have used celestial guidance since the 50s. https://airandspace.si.edu/collection-objects/snark-guidance...
Ring Laser Gyroscopes are another nifty nav tool in this space: https://en.wikipedia.org/wiki/Ring_laser_gyroscope#/media/Fi...
Earlier quoted context omitted.
The F22 had an unintentional problem of being unable to cross the international date line, which was discovered when attempting to fly from Hawaii to Japan. Given that it may very well be better to assume that anything untested doesn't work at all and to live within those restrictions.
The International Date Line and the 180-degree line of longitude have bitten a _lot_ of folks who don't think to test at the boundaries.
You get "Sorry, we could not calculate driving directions from "Wairiki, Fiji" to "Welagi, Fiji"
https://www.google.com/maps/dir/Wairiki,+Fiji/Welagi,+Fiji/@...
You can see one of these up close - both the device, and the airplane! - at the Evergreen Aerospace Museum in McMinnville, OR. They also have on display another Blackbird payload labeled DEF-H. It’s a nondescript white box which you are allowed to look at, but not allowed to know what it does. XD
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Also B-58
celestial navigation is 4000 years old
If you see the night sky every night (without distracting screens), the shapes became kind of familiar.
ICBMs have used celestial guidance since the 50s. https://airandspace.si.edu/collection-objects/snark-guidance...
No GPS in the apocalypse. Ring Laser Gyroscopes are another nifty nav tool in this space: https://en.wikipedia.org/wiki/Ring_laser_gyroscope#/media/Fi...
https://en.m.wikipedia.org/wiki/Advanced_Inertial_Reference_...
How does it see the stars? Even modern CMOS image sensors cannot see the stars during the day.
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Is it true that military branches (navy, airforce) from around equator use a grid-square reference system for radars and have issues when going further north, while triangle-based reference systems are a really good model in polar countries that doesn’t scale well when going South? It’s a problem so predictable that I can’t believe I have been told the truth, and it’s impossible to find the right keywords to search t…
The military does use a grid square reference system, Military Grid Reference System (MGRS), and to resolve the issues when sufficiently far north, the grid squares stop being aligned with the latitudes and longitudes, but rather just sit lined up with the 0/90/270/180 longitudes, as a sort of circular cap cut out of grid paper. (Properly speaking, it's Universal Transverse Mercator (which is a series of 60 Mercator…
