when GpsDrive loses view of satellites it still logs position with dummy 1001.0 coords (but real timestamp).
why record this? it just wastes space.
if there is a desire to indicate a break between a contiguous string of good fixes, maybe just insert one extra newline when the fix is first lost.
the gpx logger seems to break these using <trkseg> within the same <trk>, which is nice. (or at least it breaks trkseg for some reason, I have to check if the times line up with .sav going to 1001.0s)
to get rid of it is all that is needed to modify
storepoint() by replacing "add_trackpoint(1001.0, ..." with ";" ? [src/track.c line 171]