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NMEA Logging

GSG offers the possibility to log a scenario’s execution in NMEA data. Every second a “snapshot” of the user and satellites’ status is taken and recorded in the form of 3 standard NMEA sentence types.

  • RMC sentence describes essential GPS position, velocity and time
  • GGA sentence describes essential fix data, providing 3D location and accuracy data. Height of geoid above WGS84 ellipsoid is being approximated according to EGM96 geoid model and fix quality defaults to GPS fix (SPS).
  • GSV sentences (1 to 4 depending upon the number of SV’s) describe the actual satellites in view.

    NOTE: In GSV sentences, an SV’s SNR estimate is given based on the following:

    When noise is ON:

    SNR = CNo - NF

    When noise is OFF:

    SNR = min (56, Channel Power + BN - NF - Lc)

    Where NF is (“Noise Figure” of receiver) = 1,

    Lc (cable loss) = 1,

    and BN (background noise level) = 174 dB

You can access this "snapshot" by using the SCPI command SOURce:SCENario:LOG?, which can be queried at a maximum rate of 1Hz. See the GSG SCPI Guide (Command Reference) for more details.

It is also possible to use StudioView to log NMEA data: Tools > Data Recorder.