# Do MEMS or optical gyroscope record Earth's rotational and revolutional angular velocities?

I am using a 3 axis gyroscope (Android device) to record angular velocities using a sensor data logger application.

When the device is placed stationary, the gyroscope recorded the following values:

• X: 0.003
• Y:0.00042
• Z:0.0045

At an instantaneous time t.

If I resolve the vector components to find angular velocity using the below formula, (Is this formula correct btw?)

The angular velocity of the device = sqrt(0.0000009+0.0000001764+0.00002025) =0.0046 rad/sec = 0.26 deg/sec

What is the reason that the device is calculating a rotational speed of 0.26 deg/sec even when the device is stationary?

The Earth's rotation rate is only 0.0041 deg/sec. What am I missing here? Is this a calculation mistake or is this due to the sensor noise?

I am aware that cheap sensors used in Android devices are susceptible to noise data.

What I wanted to know is:

1. Do gyroscopes in general (fiber optic gyroscopes and MEMS gyroscopes) record the angular velocity of the Earth's rotation around its own axis?
2. Do gyroscopes also record the angular velocity of the Earth's revolution around the sun?

If the angular velocity of the Earth's rotation and Earth's revolution around the sun is recorded by the gyroscope, what is the optimal method to remove it?

Update

1. For the final project we are using fibre optic gyro scope to measure orientation of a ground vehicle, The above experiment was only for Proof of concept using MEMS IMU.

However I understand that due to difference in sensitivities of measurement and error factors in MEMS and Fibre optic gyroscopes these devices may or may not measure earth's rotational velocity (It is possible for fibre optic gyroscope to measure earth's rotational rate i.e., earth's angular velocity)

Goal

My end goal is to design a system which records the orientation of a car in 3D space for a time period of 24 hours using a fiber optic gyroscope,

However if fiber optic gyroscopes record earth's rotational rate velocities I am here to ask for the method of compensation of these velocity from my gyroscope readings. Since rotational velocity of earth is subjected to change in each axis of gyro to give different values w.r.t orientation of device on earth, what is the optimal method to remove earth's rotational velocity from gyroscope readings any literature/Research Papers recommendation for this specific topic will be helpful I am using integration for the recorded angular velocities to find the angular displacement in each axis.

• Instead of Earth's angular velocity, what you are measuring is the gyro drift . A common phenomena of MEMS gyroscope. About the possibility to measure the rotation of Earth: I'm not really sure
– Dave
Mar 15 at 6:58
• To get rid of the gyro drift, you should really take into consideration to fuse that data with an accelerometer and take an IMU instead of only gyros. Thank to the data fusion you get the most of the drift away from your data
– Dave
Mar 15 at 7:01