Reimplement attitude service

[pacjac]

• [ ] Evaluate algorithms
• [ ] Evaluate AHRS library: Data Streams? Performance?
• [ ] Generate test data set

[pacjac]

See #38 (Refactor msb_attitude.py) for additional detail, possible duplicate.

Should also cover #26 and #13.

[k323r]

@kawindme As mentioned in #26 , the imu features a digital motion processor, that should - in theory - be able to provide a orientation quaternion out of the box. The issue with this feature is, that the attitude estimation is done by a fpga, whose firmware is a proprietary, binay blob that is tedious to flash onto the imu. There are some examples out there of people, that have gotten it to work. Might be worth it to investigate.

[k323r]

So, here is a list of available open-source code snippets, that deal with the ICM-20948 in one way or the other:

• Sparkfun ICM-20948 library: https://github.com/sparkfun/SparkFun_ICM-20948_ArduinoLibrary This library includes the firmware for the digital motion processor
• Simple AHRS project, also written for Arduino: https://github.com/drcpattison/ICM-20948/blob/master/src/ICM20948.cpp This library demonstrates how to use the fifo to record bias values and how to then use the bias registers of the chip to correct for the biasses non-manually
• Linux kernel module: https://github.com/h20201400222/ICM_20948
• STM32 driver: https://github.com/mokhwasomssi/stm32_hal_icm20948/blob/master/icm20948.c
• ZaneL's library, a wrapper around the official invensense code: https://github.com/ZaneL/Teensy-ICM-20948
  • A Node JS tool to visualize the orientation of the imu: https://github.com/ZaneL/quaternion_sensor_3d_nodejs
• Python implementation supporting DMP: https://github.com/laughingrice/ICM20948
• Another kernel module utilizing the IIO framework of the kernel: https://github.com/sittner/icm20948-mod Unfortunately, loading the kernel module fails with the error message: "unknown symbol in module"
• Pimoroni ICM-20948 python library: https://github.com/pimoroni/icm20948-python
• Simple, generic C driver for the ICM-20948: https://github.com/stephendpmurphy/icm20948/tree/main
• Kernel drivers for Invensense IMUs: https://github.com/klekkala/inv_mpu unfortunately, these are for the older MPU IMUs from Invensense. Also, a kernel recompilation is required in order to use these
• Yet another STM32 HAL driver: https://github.com/CoryCline/ICM20948
• Nice examples of how to implement different functionalities of the ICM-20948: https://wolles-elektronikkiste.de/icm-20948-9-achsensensor-teil-ii

Other useful ressources:

• https://i2c.wiki.kernel.org/index.php/Main_Page
• http://smbus.org/specs/smbus20.pdf
• http://www.netzmafia.de/skripten/hardware/RasPi/RasPi_I2C.html

[k323r]

msb_attitude has been reimplemented with a complementary filter in #123