NorthStar 951 用户指南
Page 62
951/952 Operator’s Manual Rev. B
Chapter 5 - Determining Position Coordinates
Viewing speed and
course
Near the bottom of the GPS POSITION screen, your SOG and
COG are displayed in large digits.
COG are displayed in large digits.
NOTE:
The unit’s speed and course readings are the result of instantaneous
measurements derived from satellite signals. GPS speed is updated
every second. You can average these readings over a short period of
time, however, by changing the GPS speed averaging value (see ”Chang-
ing receiver options” starting on page 164).
measurements derived from satellite signals. GPS speed is updated
every second. You can average these readings over a short period of
time, however, by changing the GPS speed averaging value (see ”Chang-
ing receiver options” starting on page 164).
Viewing geodetic
datum
In the center of the GPS POSITION screen, the unit displays the
name of the datum currently in use. The datum describes the
reference of the chart you’re currently using (the reference
datum used is indicated on the label of each cartridge). Most
new charts use the NAD83 or WGS84 datum, which are nearly
identical. Make sure the datum the unit is using matches the
datum shown on the cartridge label. Specifying the wrong
datum can significantly reduce accuracy. For more informa-
tion on selecting the datum for your area, see the Northstar
951/952 Installation Manual.
name of the datum currently in use. The datum describes the
reference of the chart you’re currently using (the reference
datum used is indicated on the label of each cartridge). Most
new charts use the NAD83 or WGS84 datum, which are nearly
identical. Make sure the datum the unit is using matches the
datum shown on the cartridge label. Specifying the wrong
datum can significantly reduce accuracy. For more informa-
tion on selecting the datum for your area, see the Northstar
951/952 Installation Manual.
Viewing GPS status
At the top center of the GPS POSITION screen is a brief status
summary of the GPS receiver. Table 2 below shows the various
status messages the unit may display, along with their mean-
ings.
summary of the GPS receiver. Table 2 below shows the various
status messages the unit may display, along with their mean-
ings.
Table 2: Definitions of GPS status messages
Message
Meaning
COMM FAIL
communication link to GPS sensor has failed—unit needs repair.
3D NAV
navigating with 4 or more satellites in 3-D mode.
2D NAV
navigating with 3 satellites in 2-D mode.
TRACKING
one or more satellites are being tracked.
ACQUIRE
trying to acquire satellites.
SKYSEARCH
searching for satellites with no previous information.