(b.) Observer headset connector. Al-
ows connection of observer headset.
(c.) GPS Zeroize switch. Actuating
he guarded switch, placarded ZEROIZE GPS, will
declassify the GPS receiver.
(d.) GPS key connector. Connects
(e.) Load switch. This pushbutton
switch initiates loading process.
(f.) Load status indicator light. Illu-
ninates to indicate load status.
(g.) Dust cap. Covers GPS key con-
lector when not in use.
(h.) Observer microphone connector.
Connects observer microphone.
(i.) GPS time of day switch. This
pushbutton switch is used to transmit GPS time of
day to Have Quick II radios.
GPS System Modes of Operation.
(1.) Off Mode. When the PULL OFF
node has been selected, power is removed from the
system, except panel lighting.
Critical memory and other circuits which
cannot be turned off remain powered by
batteries in the receiver.
(2.) Initialize Mode. When the INIT (ini-
tialize) mode has been selected, position and time,
estimates can be entered via the keypad. Waypoint
data may be entered and examined, and option se-
lections made. No navigation functions can be per-
(3.) Navigation Mode. Selection of the
NAV (navigation) mode enables normal GPS func-
tions (satellite tracking and navigation), including
data transfer to and from other aircraft systems.
(4.) Test Mode. Selection of the PULL
TEST mode initiates a full command test of GPS
user equipment for line replaceable unit (LRU) fault
identification and isolation.
d. GPS Normal Operation.
GPS Start Procedures. The GPS must
be initialized prior to being used for navigation.
There are three types of start: normal, quick, and
cold. A position estimate, time estimate, and alma-
nac (or ephemeris) data are required for normal
start. A quick start uses stored position, time, and
recent ephemeris information. A cold start is used
only when the GPS is unable to perform a normal
(a.) GPS Normal Start.
Mode selector switch - INIT.
When built-in-test is com-
plete the display will show
data corresponding to the
data selector switch position.
Data display will not be illuminated for
about 30 seconds after GPS has been
turned on. Ensure that the display bright-
ness control has been set to the full clock-
wise position to receive the INIT display,
then adjust as desired.
If the GPS has been OFF for more than
30 seconds when INIT mode was selected,
the set will perform the initial built-in-test
which takes approximately 30 seconds.
Data selector switch - POS.
If ENTER POS message is
displayed press line select
key 3 next to message. Posi-
tion must be entered.
Displayed position - Check.
Verify or enter new updated
position and altitude as re-
Data selector switch - TRK-
GS. Verify correct track and
groundspeed are displayed.
If not valid, enter correct
Slew key-Press. Enter cur-
rent time, year, and day of
year on page 2.
Prior to next step, ensure all required ini-
tialization data has been entered correct-
ly, as they cannot be changed after selec-
tion of NAV mode.
Mode selector switch - NAV.
GPS will begin to search fol