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Posted by yassa9 22 hours ago

Geolocating a random island using geometry and CUDA programming(yassa9.github.io)
483 points | 78 comments
NKosmatos 21 hours ago|
Excellent write up and an enjoyable read! Reminds me of the “good old times” where posts on HN were written by humans and with a specific writing style like yours. You could’ve used a little bit more of geoguessing to narrow down results, or do a brute force visual check on the last hundred or so ;-)
yassa9 21 hours ago||
yea, thanks :D , I used a tiny idea from geoguessing, that I banded the search on islands only in latitude between -30 to +30 deg. based on the sky and the tropical vibes in the img , and it worked !
jambalaya8 19 hours ago||
agree! AWESOME work!
bmurray7jhu 21 hours ago||
For drones and missiles, this technique is known as Terrain Contour Matching. If terrain contour are measured optically, navigation is independent of RF jamming, unlike GNSS.

https://en.wikipedia.org/wiki/TERCOM

openasocket 18 hours ago||
It’s an effective a surprisingly old technique, being used on cruise missiles as early as the 1960s. It actually precedes GPS and satellite navigation by several decades. Im continuously blown away by what engineers were able to do in that era with such limited computing power. Take a look at SAGE, for example.

Fun fact: the usage of TERCOM in the tomahawk missile actually limited its ability to be used in Operation Desert Storm. Routes had to be planned to go around actual topographical features, instead of hundreds of miles of flat desert.

4gotunameagain 17 hours ago||
Rumour has it that they achieved the first TERCOM using the then revolutionary bit slicing technology.
yassa9 21 hours ago||
oh, wow, I didnt know that existed, thank u, sure gonna look into it
zer0x4d 18 hours ago||
Super fun! Interestingly, this is how JPL was able to significantly reduce the Mars 2020 landing radius on Mars. Cameras onboard take pictures of the terrain and match that to maps to figure out where the lander is. https://www-robotics.jpl.nasa.gov/what-we-do/flight-projects...
yassa9 18 hours ago|
omg wow, thats super hard, although cool ,
zer0x4d 17 hours ago||
It was cool, very fun 3 years of my life working as a part of that team :)
CamperBob2 11 hours ago||
Thanks for your service! Awesome work, I'm envious.
lexlambda 22 hours ago||
OpenStreetMap data really is a godsend for such OSINT purposes. Works much better in populated areas too, with more features like roads, shops, electric lines that can be used to search.
GaryNumanVevo 20 hours ago||
Claude / Gemini + OSM Turbo is a crazy you can do natural language queries like "find me a bus stop in germany that's surrounded by more than 5 three story buildings"
yassa9 22 hours ago||
yea , heard about them before, but didnt know that whole treasure till I really used it , impressive
dwa3592 20 hours ago||
This is awesome. I worked on something similar a few months ago. It is a general purpose navigation system based on TERCOM and dead reckoning - https://github.com/deepanwadhwa/anumaan
deiptx 18 hours ago||
I find it highly ironic that his is the second article on the main page right after "avoid building technologies that could be used by a police state".
E-Reverance 8 hours ago||
I don't see it, did he delete it?
fhn 16 hours ago||
EVERY technology could be used by a police state
esafak 14 hours ago||
It is a question of how adversely empowering the technology is.
treyd 12 hours ago||
A help with this is the sun is to the left and it seems to be midday, so you could answer the "cardinal direction" question just from the picture with "west ish", which is what it turns out to be.
yassa9 11 hours ago|
I tried to use the sun info , but honestly I couldn't at all,

thx for the tip

treyd 7 hours ago||
It'd probably be hard to do directly/algorithmically, but the shadows from the trees is what I was looking for visually.
sllabres 17 hours ago||
People liking this post will probably like this [1] and especially these [2] from the channel. All solved using algorithms and map data.

[1] https://www.youtube.com/@colsto

[2] https://www.youtube.com/watch?v=eY-W9gmwxhg https://www.youtube.com/watch?v=nzytWZPyuEw https://www.youtube.com/watch?v=rkmXs_7hELg

o4c 20 hours ago||
Really great article! OP, you did an awesome job breaking down a complex problem into manageable chunks and synthesizing the solution.
yassa9 20 hours ago|
thanks, appreciate it
ImJasonH 20 hours ago|
Excellent read, I loved it.

Incidentally, the image seems to be the one the resort uses on their website! https://oanresort.wixsite.com/chuuk

yassa9 20 hours ago|
thanks, and yea, it should be solved easily by passing the img to google lens, the website is the first result, but I found a fun opportunity to solve it in different way
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