Patent ID: 8200436

Claim:
A method of measuring attitude for wellbore survey comprising: initializing a sensor apparatus under stationary condition, the sensor apparatus including three gyroscope units oriented orthogonally respective to each other and three accelerometer units oriented orthogonally respective to each other under stationary condition in a wellbore, each of the gyroscope units having a plurality of gyroscopes with input axes parallel to each other and each of the accelerometer units having a plurality of accelerometers with detection axes parallel to each other; moving the sensor apparatus in a wellbore after initializing; generating a single output data based on outputs from the plurality of gyroscopes included in each of the three gyroscope units; generating a single output data based on outputs from the plurality of accelerometers included in each of the three accelerometer units; determining three orthogonal, incremental velocities for the sensor apparatus based on the output data generated from the three accelerometer units; determining three orthogonal, incremental rotation angles for the sensor apparatus based on the output data generated from the three gyroscope units; and determining attitude and position of the sensor apparatus in the wellbore based on the three incremental velocities and the three incremental rotation angles.