The Adafruit receiver outputs NMEA format data. The lat/lon values are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This restricts the resolution of the values. Some receivers and newer NMEA specs support more digits past the decimal point. Receivers that support native binary formats that report lat/lon as 32-bit floats show similar quantization.
The Thunderbolt has a command for entering the receiver position, but it uses 32-bit floats. This restricts the accuracy that you can enter a position. Lady Heather's precision survey routines can calculate a position to greater accuracy. In order to save the high-accuracy calculated position it uses the rather nasty technique of doing single-point self-surveys until one happens to be within a foot or so of the calculated position.... that can take an indeterminate amount of time to happen, but eventually gets the job done. ----------------- > The Adafruit plot seems to have quantization. Are the values being "snapped" to a grid in any way? _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
