Hemisphere GPS Crescent Vector H220 - Page 41

H220 Integrator Guide Appendix B-Troubleshooting Page B3
Table B-1: Troubleshooting (continued)
Issue Possible Solution
No GPS lock
 Check integrity of antenna cable
 Verify antenna’s view of the sky
 Verify the lock status and signal to noise ratio of
GNSS satellites (this can often be done on the
receiving device or by using SLXMon)
No SBAS
 Check antenna cable integrity
 Verify antenna’s view of the sky, especially towards
that SBAS satellites, south in the northern
hemisphere.
 Verify the bit error rate and lock status of SBAS
satellites (this can often be done on the receiving
device or by using SLXMon - monitor BER
value).
 SBAS corrections are only applied to the position, not to
the heading. If SBAS lock is lost, you will still have the
same heading accuracy, but your position accuracy
ma
y
be de
g
raded.
No DGPS position in external
RTCM mode
 Verify that the baud rate of the RTCM input port
matches the baud rate of the external source.
 Verify the pinout between the RTCM source and the
RTCM input port (the “ground” pin and pin-out must
be connected, and from the “transmit” from the
source must connect to the “receiver” of the RTCM
input port).
Non-DGPS output
 Verify H220 SBAS and lock status (or external source
is locked).
 Confirm baud rates match an external source correctly
 Issue a $JDIFF command and see if the expected
differential mode is in fact the current mode.
 Differential corrections are only applied to the position,
not to the heading. If differential lock is lost, you will still
have the same heading accuracy, but your position
accuracy may be degraded.