Extract summaries from pds tracks
get_tracks_descriptors.RdThis function extracts summaries from the tracks of pds data useful to the
validation. The function extracts start_end_distance: the distance
between the initial and the final point of a trip, the outliers_proportion:
the proportion of track points exceeding 30 m/s in a trip,
the timetrace_dispersion: a measure of the the irregularity in the tracking
signal.