Analysis of raw GPS data shows that the error in position is the
greatest in the transition from invalid (no GPS fix) to valid (3D
GPS fix) data for N 4 3. Deviation from the actual position can be
over 50 m. After a certain time this error is minimized. Rule
2 minimizes this type of error as follows:
Skip the next 5 GPS positions AND filter maximally the next
5 GPS positions