Operation
Chapter 3
SMART6-L User Manual Rev 3
24
3.3.4
Configuration Notes
For compatibility with other GNSS receivers and to minimize message size, it is recommended using the
standard form of RTCA, RTCM, RTCMV3 or CMR corrections as shown in the base and rover examples
above. This requires using the
INTERFACEMODE
command to dedicate one direction of a serial port to
only that message type. When the
INTERFACEMODE
command is used to change the mode from the
default, NOVATEL, you can no longer use NovAtel format messages.
To mix NovAtel format messages and RTCA, RTCM, RTCMV3 or CMR messages on the same port,
leave the INTERFACEMODE set to NOVATEL and log out variants of the standard correction messages
with a NovAtel header. ASCII or binary variants can be requested by simply appending an "A" or "B" to
the standard message name. For example on the base station:
interfacemode com2 novatel novatel
fix position 51.11358042 -114.04358013 1059.4105
log com2 rtcm1b ontime 2
Using the receiver in this mode consumes more CPU bandwidth than using the native differential
messages as shown in
Section 3.3.1, Base Station Configuration
on page 22.
At the rover station, leave the INTERFACEMODE default settings (interfacemode com2 novatel novatel).
The rover receiver recognizes the default and uses the corrections it receives with a NovAtel header.
The
PSRDIFFSOURCE
and
RTKSOURCE
commands set the station ID values which identify the base
stations from which to accept pseudorange or RTK corrections respectively. These are useful commands
when the rover station is receiving corrections from multiple base stations. Refer to
An Introduction to
GNSS
for more information on SBAS, available from
www.novatel.com/an-introduction-to-gnss/
.
All PSRDIFFSOURCE entries fall back to SBAS (even NONE) for backwards compatibility (assuming
SBAS was enabled).
At the base station it is also possible to log out the contents of the standard corrections in a form that is
easier to read or process. These larger variants have the correction fields broken out into standard types
within the log, rather than compressed into bit fields. This can be useful to modify the format of the
corrections for a non-standard application or to look at the corrections for system debugging purposes.
These variants have "DATA" as part of their names (for example, RTCADATA1, RTCMDATA1,
CMRDATAOBS and more). Refer also to the
OEM6 Family Firmware Reference Manual
detailed
descriptions of the various message formats.
Information on how to send multiple commands and log requests using DOS or Windows can be found
on our Web site at
www.novatel.com/support
.
3.3.5
GLIDE
™
SMART6-L contains NovAtel’s GLIDE which is a positioning algorithm for single-frequency GPS and
GPS/GLONASS applications. GLIDE produces a smooth position output tuned, for applications where
time relative accuracy (pass-to-pass) is more important than absolute accuracy. Because of this, it is well
suited for agricultural applications.
Multipath signals tend to induce time varying biases and increase the measurement noise on the L1/L2
pseudorange measurements. Carrier phase measurements are much less susceptible to the effects of
multipath. The GLIDE algorithm fuses the information from the L1 code and the L1 phase measurements
into a Position Time Velocity (PVT) solution.
GLIDE includes settings for a dynamic mode, a static mode and an “auto” mode, where the filtering
parameters are automatically adjusted as vehicle velocity varies between stationary and dynamic states.
