We plan on using the NEO-M8U GPS Dead Reckoning sensor on a “fast” e-bike (~45km/h top speed). So far I am unable to get the fusion mode to be enabled/the sensor to be calibrated correctly. I have driven around on the E-Bike for around 45minutes, performing the various maneuvers mentioned in the tutorial: stopping, turning (left/right) and reaching speeds over 30km/h. These were also performed in an open area. I am using a passive GPS-antenna uFL with 1dBi of gain (don’t know if that could also be the issue).
As E-Bikes typically have more vibrations than your average car, I am wondering if there is too much vibration/noise for the IMU to calibrate correctly using an E-Bike? Does anyone have any experience with this?
Basically I have two questions:
can you calibrate the NEO-M8U GPS Dead Reckoning module with an E-Bike (45km/h, more vibrations than car)?
can you calibrate the sensor on a car and then use it on the E-Bike, or will there be too much noise during E-Bike operation that was not present during calibration?
Unfortunately, it’s hard to tell. Ublox originally designed their chip to be specific for an automotive so there could be issues. I would try revisiting their documentation: https://www.u-blox.com/en/docs/UBX-1300 … %2Cnull%5D.
If it still doesn’t work then I would reach out to Ublox for their suggestions.
Hey @heckers, I’m the engineer that designed the dead reckoning boards (and many of our other GPS boards). I’m sorry to be the bearer of bad news but the M8U and the F9R do not support dead reckoning on bikes. The module itself does not account for the pivoting of a bike and so probably restarts calibration every time that you turn. I actually had asked an engineer at ublox about this during our products’ development. They do have other dead reckoning modules that do support bikes, and I’m foggy on which ones those were, but for whatever reason those capabilities were not put into the these two modules.
As to your second question, if you calibrate the module on something else, then it will not give you accurate readings when attached to a different vehicle. The calibration process is really about the module calibrating to the vehicle its attached to, not about calibrating the module so that its functional - if that makes sense.
I agree with adding a warning or notification. Thank you @heckers for pointing this out for us! We’ll notify our internal teams to get this resolved for the future.
Okay, btw is it possible to read out the IMU, for example using Example2_getIMUData, without calibrating first? When I run Example2_getIMUData on the uncalibrated unit I am unable to get any readings. Do I need to calibrate with a car first or can you somehow override the calibration status and just obtain the factory IMU readings?
