3 ms·
Hmmm. What about the sensors on my phone? For a while now I've wanted to know my realtime speed in the underground sections of the local rail/metro network. I
by exikyut 5y ago
Hmmm. What about the sensors on my phone? For a while now I've wanted to know my realtime speed in the underground sections of the local rail/metro network.
I suspect the most accurate measurements would be done using wideband SDR, iff I were able to acquire absolute position references for the signals I was seeing. Not likely, especially for something I might like to let others play with and/or generalize.
Everywhere I read about the subject the general consensus is that using accelerometer and gyro data from the average phone is a fool's errand. I have zero experience with the field so I wouldn't know if failure was incorrect signal processing or just had sensors.
- londons_explore 5y agoWithout wheel speed sensors, distance and speed errors quickly accumulate. With a particle filter and enough computation, that error can be eliminated after the fact. Ie. At the time you won't know where you are, but after you get out of the metro and the particle filter reconverged you'll know where you were with more accuracy at some point in the past.
- exikyut 5y agoAh. I see. Thanks very much for that insight - so that's why it's possible, but not generally interesting and/or widely pursued.