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Tilt Drift Correction

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Virtual Reality Engineering
Prof. Steve LaValle
Department of Multidisciplinary
Indian Institute of Technology, Madras

Lecture – 13
Tracking Systems (tilt drift correction)


The drift errors tend to accumulate over time. So, drift error if left unchecked may grow out a linear rate, may grow faster than that, may slower than that it depends on a number of things.
If you go faster or slower the rate may change and these curves may go up or down.
Correcting for drift errors:
- Use another sensor to provide a world reference
- Gradually apply corrections o Fast enough to fully compensate for drift o Slow enough to avoid simulator sickness Separate rotational Error to two components:
- Tilt error (Pitch and roll), need an “up” sensor
- Yaw Error – need a compass
So, let us suppose we have this perfect up sensor and it is accomplished by a three axis three axis accelerometer. So, it is measuring X, Y, Z components as meters per second squared and then I want to take a look at this in a particular coordinate frame.




Simple way to correct: Complimentary Filter
Gain  > 0,   0 (e.x.  = 0.0001)
In each t,

Problem: Accelerometer measures


Virtual Reality Engineering
Prof. Steve LaValle
Department of Multidisciplinary
Indian Institute of Technology, Madras

Lecture – 13-1
Tracking Systems (yaw drift correction)
Use Magnetometer to correct yaw error
Similar to tilt correction
- Calculate estimated error
- Gradually apply correction using complimentary filter Problems:
- Sensor measures vector sum of Earth’s field, building field, and board field
- Calibration hard
- Field might vary over time and position
- Soft iron bias