Simrad HS50 - Manual (Page 46)

Simrad HS50 Heading Sensor
38
20221081 / F
In this display, a number of additional information on the
heading solution is presented. This information is mainly used
for troubleshooting the system.
An explanation of the information shown is as follows:
Gps hdt The heading determined from GPS alone.
Deviation The difference in heading determined from GPS and the internal
gyro element.
Accuracy The instantaneous heading accuracy determined from GPS
alone. The instantaneous accuracy might differ from the
specified accuracy which is a figure determined for the
combination of GPS heading and heading from the internal data
element. The specified accuracy figure for the product is also
calculated as a standard deviation over a number of samples.
The figure shown as Accuracy might occasionally be higher
than the specified heading accuracy. If the Accuracy figure
shown is much higher (3 times or more) than the specified
accuracy, then the performance of the system is poor. Check
Reduced heading indication, page 48 in this manual for
troubleshooting the system.
Last heading This is the time since the system calculated the GPS heading. If
GPS signals drops out this figure will increase. In the first 300
seconds after loss of GPS heading, the heading output is
determined from the inertial element. After 300 seconds of loss
of GPS heading in the system the output of heading data will
terminate. If so, see Invalid Heading, page 47 for trouble
shooting the system.
Common sat. Shows the number of common satellites seen by the two GPS
antennas. The number of common satellites have to be two or
higher to determine heading. If the number is less than two, see
Invalid Heading, page 47 for trouble shooting the system.
The other information in this display is only of interest to
service personnel.
Number of satellites used in the GPS position fix with indication
of increasing or decreasing azimuth (Az) and elevation (El).
This display is mainly used by service personnel.