The time stamp located at the header of any NovAtel log is accurate to 20 nano seconds which is what is specified in our receivers` datasheets.
We use the term latency when referring to the time between the PPS (leading edge) and the first bit being transmitted on a COM port. Our internal tests show latency values of around 15 ms when logging messages over COM ports.
This means that the time reported in a log is accurate to 20 nano seconds, but the log will be reported roughly 15 ms after the event has passed, if using serial connection. We do not specify latencies for USB or Ethernet as other protocol latencies and hardware specific parameters are involved.