Apologies if this has been posted about before, my google fu is failing.
Implementing TDOA (currently at two anchors) and seeing about a 6.3us difference between the two anchor’s clocks after sync. The error is nearly consistent, but not precisely so.
once upon resync they actually hit 0 error and I was getting real distance measurements.
Any ideas what might be causing the offset? Is this a magic number somewhere?
Editing to add some more data: I ran a longer-term test this evening just collecting data. The TDOA results are here:
With a detail view here:
So… good news: the “bottoms” of these wells are the correct measurement. The wells are 5 seconds wide, which is the resync interval for this test. They’re surprisingly consistent, but with what looks like aliasing to me.
The clock and the sync signal are asynchronous. I would have expected this to cause at-most a 1/(38.4MHz) error, but it appears to cause an error on the order of 230x38.4MHz?
Looking into making this synchronous…