Geotagging accuracy

When using the pixhawk with a camera trigger and using the 3DRobotics flight logs for GPS data. How accurate is the pixhawk translating that data?

What I mean by this, say we have a highly accurate RTK GPS. How is the pixhawk handling that geotagging between the trigger for the camera shot and the estimation of location based upon the GPS Update frequency?

Does it just round to the nearest GPS data input? Does it estimate the location of the camera trigger based on the direction and time from the last GPS update or the next one?

Does it always round up or down to the nearest GPS update?

What GPS update rate is typically seen?

Is it better to use a RTK GPS connected to the camera instead of on the pixhawk for more accurate GPS data or is the pixhawk doing a good job of estimating the current GPS location? … e=activity

our system can triggered by outside signal, and record the time (+/-20ns to GPS UTC) and coordinates. so maybe it can help.