Android compass application that contains an animated compass along with the current device coordinates. It requires the following sensors:
- Accelerometer, used to isolate the force of gravity on all three axes by applying a low-pass filter on the accelerometer's readings.
- Magnetometer, used to get the readings for the device's magnetic environment for all three axes
- GPS, used to get longitude and latitude. I calculate the device's tilt angle and rotation matrix by converting a vector from the device's coordinates system to real world coordinates system. Keep in mind that RotationMatrixGravity = magnitude of gravity and TiltAngleRotationMatrix*Geomagnetism = magnitude of geomagnetic field Then, I use the Rotation Matrix to get the device's Orientation and then get the Azimuth which is used to create the compass' arrow animation.
Sensor Sampling rate = 20.000 μs = 0.02 s
The application has the added functionality of writing visited coordinates to a log file (no duplicates).
Besides the aforementioned sensors, it requires minimum Android version 6.0 (API Level 23). Permissions:
- ACCESS_FINE_LOCATION
- WRITE_EXTERNAL_STORAGE
- INTERNET
