A software thing I built: GPS on a 25MHz 486-SX

Posted by JPLeRouzic 7 hours ago

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Comment by SillyUsername 5 hours ago

I built one, tracking fleet vehicles with a custom box, using tiled maps, on behalf of Vodafone, back in 2002. I still remember I wrote a basic trans-mercator library too!

Of course Mercator projection may go out of fashion soon https://www.independent.co.uk/news/world/africa/world-map-eq... :)

Hope I'm called back to update the library ;)

Comment by philipallstar 2 hours ago

Probably not if navigation is involved:

> This is why most online mapping platforms like Google Maps or Apple Maps rely on a variation of the Mercator projection to provide directions. Using the Equal Earth projection for navigation would not be as effective as the Mercator projection.

> What the UN did was endorse the broader message that Equal Earth is a fairer projection that more equitably displays the true size of the Earth’s land

You are right about this though - it's a moral fashion. Who cares about land size on a map unless you've got the priorities and advancement of a prehistoric king? People with plenty of spare time who constantly talk in an echo chamber[0], that's who.

[0] https://un.org/en

Comment by tomaskafka 1 hour ago

A bit related - I tried if I can push Fable to write a Garmin map renderer that would be comparably fast (or faster) on Fenix 8 than the one they claim is possible on Fenix 9 only. I think I got very close, rendering detailed topographical vector map at over 15 fps on QEMU simulated single core simple CPU comparable to actual Fenix 8.

https://www.reddit.com/r/Garmin/comments/1vzaz4w/we_live_in_...

Comment by svag 5 hours ago

I believe the library mentioned in the article should be this one https://geodyssey.github.io/overview/overview.html and here https://www.lukatela.com/geodyssey/

Comment by guenthert 4 hours ago

"real-time GPS-driven moving map display"

Not the IMHO more interesting analog tech which lifts signals out of thermal noise.

Comment by JPLeRouzic 1 hour ago

That looks interesting, what technology "lifts signals out of thermal noise"?

Comment by FrankPetrilli 29 minutes ago

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Comment by ErroneousBosh 4 hours ago

One of the things I discovered a while back is that even fairly crude trig approximations don't put that much error into your position, over a small enough distance.

To calculate things like straight-line range from where you are now to where you need to put a unit for an emergency, you're probably not working over an area of more than a couple of hundred kilometres radius and the error will be within a few dozen metres. And once you get within about half a k, you're driving towards the column of smoke anyway ;-)

Comment by contingencies 1 hour ago

In Y2K I built a Linux on PC104 solution with GPS, bonded dual-channel mobile 9600 baud data links, and a (slow) image feed. It was kind of special to see the data coming over the mobile network in those days: this was before mobile data using basic PSTN modem tech! Very lossy and slow, as the algorithms did not account for mobile voice compression.

Comment by orielhaim 4 hours ago

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Comment by razashaikh92 6 hours ago

Cool software keep it up

Comment by JPLeRouzic 6 hours ago

The author says:

"It used Voronoi Cells and reduced most math to 8- and 16-bit integer calculations with one or two single-precision floating-point calculations."

I wonder if it can be used to speed up LLM inference.

Comment by Neywiny 1 hour ago

That's what quantization and stuff is, basically. So yes. Been done for years on all neural net types not just LLMs.

Comment by JPLeRouzic 1 hour ago

Please can you provide some links to intro level articles?