PinePhone Sensors and Navigation
DRAFT
Overview
The Pinephone contains various components that enable or aid orientation and navigation tasks.
- Multi-GNSS Receiver as part of the cellular modem (GPS/Galileo/Glonass/BeiDou)
- IMU (Inertial Measurment Unit), combined Accelerometer and Gyroscope sensor (MPU6050)
- Magnetometer (LIS3MDL or AF8133J)
...
[TODO: add block diagram]
Hardware
Quectel EG25G Modem / GNSS Receiver
[TODO: add interfaces, constraints, antenna location]
Invensense/TDK MPU6050 IMU
Key features:
- Digital-output X-, Y-, and Z-Axis angular rate sensors (gyroscopes) with selectable range of ±250, ±500, ±1000, and ±2000°/sec
- Digital-output triple-axis accelerometer with a programmable full scale range of ±2g, ±4g, ±8g and ±16g
- 400kHz Fast Mode I2C for communicating with all registers
ST LIS3MDL Magnetometer/Compass
Key features:
- ±4/±8/±12/±16 gauss selectable magnetic full scale range
- 16-bit data output
- ...
VTC AF8133J Magnetometer/Compass
Key features:
- ±12/±22 gauss selectable magnetic full scale range
- 400Hz max. update rate
- 16-bit data output
Sensor reference frames
The sensors are mounted on the Pinephone's main board in different positions and orientations, for the purpose of orientation and navigation it is important to know the relationship between the sensor coordinate frames and the body frame of the phone...
As a basis for software development, a common body coordinate system has to be established along with it's relation to a world coordinate system. "iio-sensor-proxy expects the (sensor) readings to match those defined in the Linux IIO documentation, the Windows Integrating Motion and Orientation Sensors whitepaper, and the Android sensor documentation"[ref]. To transform the sensor coordinates systems into body coordinates, 'mount matrices' have to be defined.
[TODO: explain body reference choices, north-east-down world coordinates]
Software
Drivers
[TODO: i2cdev, linux-iio, support matrix]
- EG25G:
- MPU6050:inv_mpu6050, inv_mpu6050_i2c, industrialio
iio:device2: mpu6050 (buffer capable) 9 channels found: accel_x: (input, index: 0, format: be:S16/16>>0) 6 channel-specific attributes found: attr 0: calibbias value: -2102 attr 1: matrix value: 0, 0, 0; 0, 0, 0; 0, 0, 0 attr 2: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 3: raw value: 912 attr 4: scale value: 0.000598 attr 5: scale_available value: 0.000598 0.001196 0.002392 0.004785 accel_y: (input, index: 1, format: be:S16/16>>0) 6 channel-specific attributes found: attr 0: calibbias value: 941 attr 1: matrix value: 0, 0, 0; 0, 0, 0; 0, 0, 0 attr 2: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 3: raw value: 516 attr 4: scale value: 0.000598 attr 5: scale_available value: 0.000598 0.001196 0.002392 0.004785 accel_z: (input, index: 2, format: be:S16/16>>0) 6 channel-specific attributes found: attr 0: calibbias value: 1242 attr 1: matrix value: 0, 0, 0; 0, 0, 0; 0, 0, 0 attr 2: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 3: raw value: 15860 attr 4: scale value: 0.000598 attr 5: scale_available value: 0.000598 0.001196 0.002392 0.004785 temp: (input) 3 channel-specific attributes found: attr 0: offset value: 12420 attr 1: raw value: -1073 attr 2: scale value: 2.941176 anglvel_x: (input, index: 4, format: be:S16/16>>0) 5 channel-specific attributes found: attr 0: calibbias value: 0 attr 1: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 2: raw value: -32 attr 3: scale value: 0.001064724 attr 4: scale_available value: 0.000133090 0.000266181 0.000532362 0.001064724 anglvel_y: (input, index: 5, format: be:S16/16>>0) 5 channel-specific attributes found: attr 0: calibbias value: 0 attr 1: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 2: raw value: 4 attr 3: scale value: 0.001064724 attr 4: scale_available value: 0.000133090 0.000266181 0.000532362 0.001064724 anglvel_z: (input, index: 6, format: be:S16/16>>0) 5 channel-specific attributes found: attr 0: calibbias value: 0 attr 1: mount_matrix value: 0, 1, 0; -1, 0, 0; 0, 0, -1 attr 2: raw value: 0 attr 3: scale value: 0.001064724 attr 4: scale_available value: 0.000133090 0.000266181 0.000532362 0.001064724 timestamp: (input, index: 7, format: le:S64/64>>0) gyro: (input, WARN:iio_channel_get_type()=UNKNOWN) 1 channel-specific attributes found: attr 0: matrix value: 0, 0, 0; 0, 0, 0; 0, 0, 0 3 device-specific attributes found: attr 0: current_timestamp_clock value: realtime attr 1: sampling_frequency value: 50 attr 2: sampling_frequency_available value: 10 20 50 100 200 500 2 buffer-specific attributes found: attr 0: data_available value: 0 attr 1: watermark value: 1 Current trigger: trigger1(mpu6050-dev2)
- LIS3MDL: st_sensors, st_sensors_i2c, st_magn, st_magn_i2c, industrialio
iio:device1: lis3mdl (buffer capable) 4 channels found: magn_x: (input, index: 0, format: le:S16/16>>0) 3 channel-specific attributes found: attr 0: raw value: 6766 attr 1: scale value: 0.000146 attr 2: scale_available value: 0.000146 0.000292 0.000438 0.000584 magn_y: (input, index: 1, format: le:S16/16>>0) 3 channel-specific attributes found: attr 0: raw value: -2046 attr 1: scale value: 0.000146 attr 2: scale_available value: 0.000146 0.000292 0.000438 0.000584 magn_z: (input, index: 2, format: le:S16/16>>0) 3 channel-specific attributes found: attr 0: raw value: 12726 attr 1: scale value: 0.000146 attr 2: scale_available value: 0.000146 0.000292 0.000438 0.000584 timestamp: (input, index: 3, format: le:S64/64>>0) 3 device-specific attributes found: attr 0: current_timestamp_clock value: realtime attr 1: sampling_frequency value: 1 attr 2: sampling_frequency_available value: 1 2 3 5 10 20 40 80 2 buffer-specific attributes found: attr 0: data_available value: 0 attr 1: watermark value: 1 Current trigger: trigger0(lis3mdl-trigger)
Userspace services
[TOOD: modem manager, ofono, gpsd, iio-sensor-proxy, geoclue]
Tools/Utilities
[TODO: minicom, gpsmon, monitor-sensor, iio-utils...]
Applications
[TODO: pure-maps, navit, ...]
Development
[TODO: Open issues, tasks, projects]
- AGPS integration
- Raw magnetometer data + calibration in iio-sensor-proxy
- Compass App