Appendix C
Frequently Asked Questions
1.Why don’t I hear sound from the SPAN-CPT?
The
Check the input power supply. A minimum of 12 V should be supplied to the system for stable
2.Why is the INS solution status ‘INS_INACTIVE’?
The INS alignment routine does not begin until the system has solved for time. This requires that an antenna is attached and satellites are visible to the system. Verify that time is solved by checking the time status in the header of any standard header SPAN log such as BESTPOS. When the time status reaches FINESTEERING the inertial filter starts and the INS begins attempting to align.
3.How can I access the inertial solution?
The INS/GNSS solution is available from a number of specific logs dedicated to the inertial filter. The INSPOS, INSPVA, INSVEL, INSSPD and INSATT logs are the most commonly used logs for extracting the INS solution. These logs can be logged at any rate up to the rate of the IMU data (100 Hz). Further details on these logs are available in SPAN on OEM6 Firmware Reference Manual
4.Can I still access the
The
5.What will happen to the INS solution when I lose GNSS satellite visibility?
When GNSS tracking is interrupted, the INS solution bridges through the gaps with what is referred to as free inertial navigation. The IMU measurements are used to propagate the solution. Errors in the IMU measurements accumulate over time to degrade the solution accuracy. For example, after one minute of GNSS outage, the horizontal position accuracy is approximately 8.4 m. The SPAN solution continues to be computed for as long as the GNSS outage lasts, but the solution uncertainty increases with time. This uncertainty can be monitored using the INSCOV log.
6.All the accels measurements in my RAWIMUS logs are zero and the IMU status shows one or all accels are failing. What is wrong?
Ensure a monotonic power supply on power up of your
7.The SPAN-CPT will not start /power on?
The
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