Novatel OM-20000122 user manual  Logging Restriction, Data Collection for Post-Processing

SPAN-CPT Operation Chapter 3

To store data from a SPAN-CPT, connect a computer. The computer should be equipped with a data storage device such as a Compact Flash Card, CD or USB stick.

 Logging Restriction

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 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:

•Raw data for post processing RAWIMUXSB ONNEW (100 Hz)

-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. See details of these logs in the SPAN on OEM6 Firmware Reference Manual (OM-20000144).

•Real time INS solution

INSPVASB ONTIME 0.01 (maximum rate equals the IMU rate)

-Other possible INS solution logs available at high rates are: INSPOSSB, INSVELSB and INSATTSB

3.7Data Collection for Post-Processing

Some operations such as aerial measurement systems do not require real time information from SPAN-CPT. These operations are able to generate the position, velocity or attitude solution post-mission in order to generate a more robust and accurate solution than is possible in real time.

In order to generate a solution in post-processing, data must be simultaneously collected at a base station and each rover. The following logs must be collected in order to successfully post-process data:

From a base:

•RANGECMPB ONTIME 1

•RAWEPHEMB ONCHANGED

•GLOEPHEMERISB ONCHANGED (if using GLONASS)

From a rover:

•RANGECMPB ONTIME 1

•RAWEPHEMB ONCHANGED

•GLOEPHEMERISB ONCHANGED (if using GLONASS)

•RAWIMUSXB ONNEW

•IMUTOANTOFFSETSB ONCHANGED

•VEHICLEBODYROTATIONB ONCHANGED

Post-processing is performed through the Waypoint Inertial Explorer® software package available from the NovAtel Waypoint Products Group. Visit our Web site at www.novatel.com/products/software/ waypoint-products/ for details.

The highest rate to request GNSS logs (RANGE, BESTPOS, RTKPOS, PSRPOS and so on) while in INS operation is 5 Hz. If the receiver is not running INS, GNSS logs can be requested at rates up to 20 Hz.

SPAN-CPT User Manual Rev 8 33