Rule 3. Changes in the number of visible satellites.
A change in the number of visible satellites leads to calculating
the position based on data involving different combinations of satellites. Therefore, the accuracy is improved or gets worse. As a
result, deviation from the previous position is within 10–30 m.
This can lead to insertion of redundant points. Rule 3 must
remove most of these points:
Skip GPS positions if 9 Ni Ni 19 4 2 AND filter maximally the
next 3 GPS positions.