Maretron DSM150, User Manual

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Revision 1.4.18 Page 233
activated. The point of reference can be selected from the current position or it can be manually
entered.
The Outside Radius Alert and the Anchor Alert are very similar. The Anchor Alert is designed to allow
the input of relatively small radius values, and may be displayed graphically through the Anchor
Watch Display (section 7.1). The radius of the Outside Radius Alert is specified in either Nautical
Miles or Kilometers, while the radius of the Anchor Alert is specified in Feet or Meters.
See Section 8.3.7.7 for details of the configuration of the Anchor Alert.
8.3.7.10 Trigger Type is GPS Quality Alert
The accuracy, or quality, of a position fix provided by a GPS is dependent on the number of satellites
used to compute the position. A position based on less than three satellites is considered a “1D” lock,
three satellites is a “2D” lock, more than three satellites is a “3D” lock, and more than three satellites
with SBAS is a “3D-DGPS” lock. These different locks are indicative of the quality or accuracy of the
given position with 1D having the lowest quality and 3D-DGPS providing the highest quality. The GPS
Quality Alert is used to alert you if the quality of the position falls below a specified quality level.
8.3.7.10.1 Trigger Configuration
– GPS Quality Alert
Figure 269
– Trigger Configuration – GPS Quality Alert
Re-trigger Period
– When you accept an alert, it will change to the “Accepted” state, and
annunciators that are sounding for that alert will stop sounding. If the condition which caused
the alert remains true after the amount of time in this field, the alert will return to
the “Active”
state, and annunciators will begin sounding again for that alert. If a value of 0:00 is entered,
then the alert will never re-trigger.
Alert Set Point
– The Alert will be triggered when the qaulity of the GPS fix, as reported by the
GPS drops lower than the value specified in this field.
Possible Values are:

3D-DGPS (best quality)

3D-GPS

2D-GPS

1D-GPS

No fix