Post #2272331

2026-05-04 23:23 UTC

@regehr@mastodon.social @penguin42@mastodon.org.uk the way it works is basically it has 4 inputs connected to normal GPS antennas and the output is a filtered signal that's connected to a normal civilian/commercial ublox module and an STM32H723. that i also dumped and tried to RE but the damn thing is full of vectorized floating point and doesn't have a single string. i found the state machine that parses the ublox binary protocol but the rest of it is a megabyte of dense thumb2+vfp code i am pretty sure i could feed it simulated GNSS data and see what it spits out though

Replies (3)

@regehr@mastodon.social 2026-05-04 23:25

@whitequark@social.treehouse.systems @penguin42@mastodon.org.uk I don't actually do RE but... a MB of assembly is almost certainly well over 90% open source software, or at least libraries from somewhere. do we have ways to searching for where a machine function came from?

Open ##2272332
@resistor@mastodon.online 2026-05-04 23:25

@whitequark@social.treehouse.systems @regehr@mastodon.social @penguin42@mastodon.org.uk Wait, does Cortex-M7 have NEON?

Open ##2272335
@whitequark@social.treehouse.systems 2026-05-04 23:25

@regehr@mastodon.social @penguin42@mastodon.org.uk oh it also has an IMU which looks exactly like an american mil-grade IMU ADIS16488 but i tracked it down to a specific chinese manufacturer that makes semi-compatible clones. i talked to it and instead of the full complement it just has gyros the gyros themselves are fun because they're vacuum-filled! for improved response i think the overall controller is a GD32 chip so it's obviously not an actual american product i ran the gyros and they don't seem that good to me in terms of noise. but i think they have very good resistance to shock

Open ##2272350