I noticed something peculiar. I have 100+ drones all same build. Build over 1 - 2 years. As a result I I have different Here+ GPS modules.
some are (first batch):
COMPASS_DEV_ID: 466441 (HMC5883)
COMPASS_DEV_ID2: 592905
COMPASS_DEV_ID3: 131874
some are (second batch):
COMPASS_DEV_ID: 723977 (ICM20948)
COMPASS_DEV_ID2: 131874
COMPASS_DEV_ID3: 263178
Both have the AK09916 compass underneath if I understand correctly.
But I noticed that the second batch usually have larger offset after calibration. I decided to investigate a bit here. I tried with shielding to improve the situation, but failed. That’s were I started to get suspicious.
So I took a build from the second batch with large offsets.
After calibration I got:
ofs_x = 47, ofs_y = -166, ofs_z = -328
I removed the GPS and installed a GPS from the first batch (466441) and after calibration I got the following:
ofs_x = -68, ofs_y = -46, ofs_z = 11
This looks very strange. I would suspect that both GPS should give similar magnitude of order offsets. Since the build doesn’t change. I only changed the GPS module.
Is the HERE+ module with ICM20948 just a version with a bad compass (compared to first iteration)?
Or is there something going wrong in the calibration causing the larger offsets?