Android- Gyro Sensor drift and Correct angle Estimation

[ravishah]

I am using LG Optimus 2x smartphone(Gyroscope and Accelerometer sensor) for positioning. I want to get correct rotation angles from gyroscope that can be used later on for body to earth coordinate transformation. My question is that 1- How I can measure and remove the drift in gyro sensor. The one way is to take the average of gyro samples (when mobile is in static condition) for some time and subtracting from current sample, which is not good way. When the mobile is in rotation/motion how to get the drift free angles?
regards navigator

[chingkui]

How many gyro and accelerometer sensors does the phone have? You most likely need 3 (orthogonal) gyros and another 3 accelerometers to do what you want to do. Also, not all sensors are created equal. To detect motion, you can use pretty low-cost sensors. To navigate accurately, the sensors have to be much better.

[shrimp]

if you combine accelerometers, gyro and GPS data using Kalman Filter, you should be able to estimate gyro bias values "in-motion". LG Optimus 2x have "not bad" sensors http://invensense.com/mems/gyro/mpu3050.html so I think everything is possible. You can use inertial sensors for motion detection, and when you detect "no motion" you can start gyro bias estimation.