T-45C TS, ADV & IUT ENG-24
GINA Operating Characteristics
D.
Precise Positioning Service (PPS)
1.
Currently, only provided to government authorized
users
2.
Horizontal positioning accuracy to 16 meters; it may
be even more accurate
3.
Applicable signals are encrypted; receiver must
have a government supplied crypto-key for decoding
E.
Timing pulse
1.
Both satellites and receivers contain highly accurate
clocks
2.
Using the known speed of radio transmission
signals, adjusted for atmospheric effects, distance
from each satellite is mathematically derived
F.
Satellite position and other information
1.
Satellites transmit ephemeris data (satellite’s exact
position in space)
2.
Satellites transmit GPS system time
3.
Satellites transmit their known clock error
4.
Satellites transmit known health and accuracy of
their data
5.
Satellites transmit ionosphereic data
G.
GPS can operate in stand-alone capacity
1.
GPS present position displayed on ACFT DATA
page
2.
GPS normally operates in conjunction with INS:
HYBD mode
NOTE: Even in DGRO mode, INS and GPS
operate together.
Original (9-98)
Page 24-18
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