Since I first got it, it had one pointing straight up, but later on it managed to point me towards the actual third blueprint. After that it was always just pointing up until I went into orbit, where it went every which way. Probably something to do with tracking between the two distinct "modes?"
If you are seeing multiple arrows then it is just tracking multiple blueprints (the radar can track up to 3 nearby blueprints), just pick one of the arrows to follow or work on a blueprint you currently have and do the others later.
If you are in the area where a blueprint is there should be an arrow pointing towards that blueprint and another arrow pointing towards orbit which is for the other blueprints, the process of finding the rest of the blueprints should be the same as the third blueprint.
