"Raw" measurements include the distance and speed of each satellite from the receiver. For each satellite, you typically get a "pseudo-range" and a "Doppler shift" measurement. The GPS receiver knows the speed and location of each satellite, so it uses the raw measurements to calculate the speed and location of the GPS receiver. The resulting values of lat, lon, altitude, direction and speed are part of the NMEA messages, but NMEA does not include the original raw measurements.
RTKLIB uses a technique called "double differencing" which absolutely requires "raw" measurements. The NMEA protocol simply doesn't include pseudo-ranges or Doppler shift data, so it is useless for RTKLIB. support raw protocol input > instead of NMEA which is popularly used in common GPS receivers. > Is there a reason for this? _______________________________________________ This message is sent to you from FOSS-GPS@lists.osgeo.org mailing list. Visit http://lists.osgeo.org/mailman/listinfo/foss-gps to manage your subscription For more information, check http://wiki.osgeo.org/wiki/FOSS-GPS
