Simrad HS50 - Manual (Page 48)

Simrad HS50 Heading Sensor
40
20221081 / F
Invalid Position alarm
Activated if the system has been unable to determine position
the last two seconds, or if the HDOP value is greater than 4.
See No valid data, page 46 for troubleshooting.
The following alarm text will be displayed:
Invalid Heading alarm
Activated 300 seconds after the system is unable to determine
GPS heading and the HDT-Q indication has become invalid.
Invalid Heading, page 47 for troubleshooting.
The following alarm text will be displayed:
Invalid Position and Heading alarm
If both heading and position data is invalid, the display will
show: