1. What are the types of north finder?
According to the different internal sensors, the north finder can be divided into FOG (Fiber Optic Gyroscope) north finder and MEMS north finder.

2. What are the sensors contained in the North finder?
FOG North finder: includes fiber optic gyro and quartz accelerometer
MEMS North finder: includes MEMS gyro and MEMS accelerometer

3. What is the structure of the North finder?
The north finder is composed by adding the north finding algorithm on the basis of IMU (Inertial Measurement Unit).
The IMU is composed of a gyroscope sensor and an accelerometer sensor.
Therefore, north seeker = gyroscope sensor + accelerometer sensor + north finding algorithm

Found more knowledge: https://www.ericcointernational.com/north-finders