The NTPviz output says, "TDOP is a dimensionless error factor. TDOP ranges from 1 to greater than 20. 1 denotes the highest possible confidence level. 2 to 5 is good." I routinely have TDOP values below 1, which this text implies is impossible: https://ntp2.wiktel.com/day/index.html#local_gps What is wrong here, gpsd or ntpviz? -- Richard