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SPAN-CPT Operation Chapter 3
SPAN-CPT User Manual Rev 8 31
3.5.2 Inertial Azimuth
The inertial azimuth computed by the SPAN inertial navigation filter. It uses the sensors in the IMU to
compute the azimuth of the IMU (this can be rotated to another reference if desired). For more
information, see the APPLYVEHICLEBODYROATION and VEHICLEBODYROTATION commands in the
SPAN on OEM6 Firmware Reference Manual
(OM-20000144).
This azimuth is the one provided in the majority of the INS logs available to a SPAN user. See Table 5,
Logs with Azimuth data on page 31.
3.5.3 ALIGN Azimuth
On SPAN systems with dual antennas, an azimuth is available from the dual antenna baseline. This is
the same azimuth that is used as an update to the SPAN solution. It is noisier than the inertial azimuth
and is available at a much lower rate, but will have a stable mean. This azimuth is computed from the
master antenna to the rover antenna based on how the antennas are oriented on the vehicle.
There is a specific subset of logs that output this azimuth. See Table 5, Logs with Azimuth data on
page 31.
Table 5: Logs with Azimuth data
Log
Log
Format
Azimuth Source
INSPVA / INSPVAS / INSPVAX NovAtel Inertial
INSATT / INSATTS / INSATTX NovAtel Inertial
PASHR NMEA Inertial
INSSPD NovAtel Course Over Ground
Computed using the INS solution only
BESTVEL NovAtel Course Over Ground
From the best system solution which could be either
GNSS or INS
GPVTG NMEA Course Over Ground
From the best system solution which could be either
GNSS or INS
HEADING NovAtel ALIGN
GPHDT NMEA ALIGN