title: iOS dead reckoning
body: <p>I'm working on an iOS project which needs me to do simple dead reckoning when GPS is not available. I've been given a bunch of measurement data from various phones which consists of the following:</p>
  
  <ol>
  <li>GPS data (x, y, z, course, speed) when available</li>
  <li>Accelerometer (useracceleration x, y, z)</li>
  <li>Gyroscope (rotationrate x, y, z)</li>
  </ol>
  
  <p>I want to compute missing GPS positions in the time series. I understand how to project locations based on last GPS position and course values, but this gives me large errors. My question is if it is possible to obtain better results if I combine the accelerometer and gyroscope data. I understand how to integrate accelerometer values to obtain speed information, but I'm not sure how to use the gyroscope data. Any help would be greatly appreciated.</p>