Chapter 4 SPAN Operation
CPT7 and CPT7700 Installation and Operation User Manual v12
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The
INSATTX
log,
INSPOSX
log,
INSPVAX
log and
INSVELX
log contain solution and variance
information and are therefore large logs. Use a low logging rate (<20 Hz) only.
These logs also contain solution uncertainty in standard deviation format.
Note that the position, velocity and attitude are available together in the
INSPVA
log,
INSPVAS
log and
INSPVAX
log.
The inertial solution is available up to a rate of 200 Hz. Data can be requested at a specific synchronous time
interval, asynchronously matching the IMU output rate, or can be triggered by the mark input trigger at rates up
to 200 Hz.
The GNSS-only solution is still available through the GNSS-only logs such as RTKPOS and PSRPOS. Refer
to the
OEM7 Commands and Logs Reference Manual
. INS-only data logging and output can be at rates of up
to the rate of the IMU data.
The highest rate that you should request GNSS logs (RANGE, BESTPOS, RTKPOS, PSRPOS, and
so on) while in INS operation is 5 Hz. If the receiver is not running INS (no IMU is attached), GNSS
logs can be requested at rates up to 20 Hz.
Logging Restriction Important Notice
Logging excessive amounts of high rate data can overload the system. When configuring the output
for SPAN, NovAtel recommends that only one high rate (>50 Hz) message be configured for output at
a time. It is possible to log more than one message at high rates, but doing so could have negative
impacts on the system. Also, if logging 100/200 Hz data, always use the binary format and, if possible,
the short header binary format (available on most INS logs).
For optimal performance, log only one high rate output at a time. These logs could be:
l
Raw data for post processing
RAWIMUXSB ONNEW
l
RAWIMU logs are not valid with the ONTIME trigger. The raw IMU observations contained
in these logs are sequential changes in velocity and rotation. As such, you can only use
them for navigation if they are logged at their full rate. Refer to the
for log and command details.
l
Real time INS solution
IMURATEPVA ONNEW or IMURATEPVAS ONNEW
l
Other possible INS solution logs available at high rates are: INSPVASB, INSPOSSB,
INSVELSB, INSATTSB
Specific logs need to be collected for post-processing. See
Data Collection for Post Processing
To store data from an OEM7 receiver, connect the receiver to a computer running NovAtel Application Suite or
other terminal program capable of recording data. On CPT7 receivers, you can also collect data on internal
memory.
4.4.5 Recommended Messages to be Logged for SPAN Data Collection
Although every customer has a different application and setup, it is important to always log as much
information about the GNSS and INS filters and the environment in which the survey is taking place. The
