I have been having some problems with "bad trackpoints" in the track logs I've been creating, especially in bad signal conditions. In some cases these obviously jump miles away from the true location; other times they are just as incorrect but resemble legitimate movement.
I've noticed that the worst of these errors tend to be limited to a specific unit at a specific time: other units will not show the same errors. For example:
Here is the same plot with some the bad trackpoints highlighted. You can see the red unit recorded a couple really bad points at one time, and at another time the blue unit recorded a whole series that resembles travel that did not actually occur.
I've been trying to manually remove this bad data using GPS Track Editor and manually selecting and deleting points that looked out of place, but that's a pain. I've also started thinking of ways I could write programs to fix it, but I'm an amateur and I suspect this is a well studied problem (but I don't know where to look).
What are some automated techniques I can use for cleaning these bad trackpoints from my track logs?
Specifically, I'm hoping to find out about:
- Techniques to reject a set of "bad points" from a single track log as "inconsistent" with the ones before or after (seems like that could catch the problem in the red track)
- Techniques to cross-check two or more track logs of the same trip against each other (may fix the problem in the blue track)
- Tools that implement the above