NorthStar 958, Руководство по установке

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958 Installation Manual, Rev. A1 Page 21
SECTION FIVE: Checking out the
system
Turning the 958 on and off
To turn on the 958, briefly press the
PWR
key. The 958 emits several short beeps as it displays the
START-UP
screen, then performs a series of self-tests to check its critical components and functions.
Next, a message is shown as a reminder against relying on the 958’s chart cartography as the only
means of safe navigation.
To see DGPS status, on the
GPS POSITION
screen, press
DGPS INFO
to display the
DGPS STATUS
screen. Check for low noise levels and mid-range SNR readings.
To see information about signals from the satellites, press
SAT INFO
.
Figure 14: Satellites on the GPS satellites screen
The satellite map on the
GPS SATELLITES
screen shows the current location of the satellites in the
sky. The 958 displays GPS satellites as circles; WAAS satellites as hexagons. You can check the
quality of their signals by looking at each satellite’s Signal-to-Noise Ratio (SNR). The higher the ratio,
the better the quality.
Although the U.S. government identifies WAAS satellites by their pseudo random number (PRN)—a
three-digit number ranging from 120 to 138—the 958 identifies them by two-digit numbers ranging
from 33 to 51. For example, the satellite for the Atlantic Operating Region (AOR) is PRN 122, which
the 958 displays as 35. See Table 5 below for the satellite identification numbers that may be
displayed on the 958’s screen.
GPS
satellite
number
WAAS
satellite
number
36