A
B
Receiver Status, EPE & DOP
Receiver status is indicated at the top of the page, with the current
estimated
position error
(EPE) and
dilution of precision
(DOP) to the left of the sky view.
DOP is an indication of satellite geometry quality measured on a scale of one to
ten (lowest numbers the best, highest numbers the poorest). EPE uses DOP and
other factors to calculate a horizontal position error in feet or meters. The status
field will show one of the following conditions:
•
Searching the Sky—
the receiver is looking for any satellites.
• AutoLocate—
the receiver is is looking for any satellite whose almanac has been col-
lected. This process can take up to five minutes.
•
Acquiring Satellites—
the receiver is looking for and collecting data from satellites
visible at its last known or initialized position, but has not collected enough data to
calculate fix.
•
2D Navigation—
at least three satellites with good geometry have been acquired and
a 2 dimensional position fix (latitude and longitude) is being calculated. ‘2D
Differential Navigation’ will appear when you are receiving DGPS corrections in
2D mode.
• 3D Navigation—
at least four satellites with good geometry have been acquired and
your position is now being calculated in latitude, longitude and altitude. ‘3D
Differential Navigation’ will appear when you are receiving DGPS corrections in
3D mode.
•
Poor GPS Coverage—
the receiver is no longer tracking enough satellites for a 2D
or 3D fix.
• Receiver Not Usable—
the receiver is unusable, possibly due to incorrect initializa-
tion or abnormal satellite conditions. Turn the unit off and back on to reset.
• Simulating Navigation—
the receiver is in simulator mode.
18
A.
The status bar at the bottom of the page displays
important status, alarm and map scale informa-
tion. It also provides on-screen user and message
prompts.
B.
The status bar will display an anchor symbol or
‘PRX’ icon whenever the anchor drag alarm or
proximity alarm has been triggered.
SECTION
1
STATUS PAGE
Receiver Status
gps 130 7/23/98 9:21 AM Page 18