Re:No GPS required: our app can now locate underground trains
by dorfsmay on Wednesday November 13, 2024 @10:39AM
(#42126963)
Do you then use the internet to find the local pressure, or only use it to calculate changes in altitude?
[ Parent
| on HN ]
Re:No GPS required: our app can now locate underground trains
by traverseda on Wednesday November 13, 2024 @05:04PM
(#42130588)
It's one factor in estimating altitude you feed into an extended kalman filter. If the GPS altitude is holding steady but there's a sudden jump in pressure that's probably a storm front not indicative of motion.
You also probably want an accelerometer.