NAV SELECT Title of screen.
RAIM Gives GPS RAIM status:
P = Pass.
F = Fail.
P-B = Pass with Baro.
F-B = Fail with Baro.
NGP = No GPS.
NA = RAIM not available.
CONTROL/ FUNCTION INDICATOR
DOP Gives Doppler status:
NAV = Nav mode.
MEM = In memory mode.
TST = In test mode.
F = Doppler inoperative.
DO-GPSs Provides blended GPS/Doppler position to navigation computer.
GPSs Provides GPS only position to navigation computer.
DOPs Provides Doppler only position to navigation computer.
VERT-NAVs Not available.
3.13.2.2 Present Position Update. Use present posi-tion update to correct for position error which builds up in the Doppler sensor when GPS coverage is not available. Updates may be accomplished by over.ying a known po-sition, .xing to GPS as a one time .x, or .xing to a TACAN position, after slant range is corrected using either radar or set point altitude. The screens used to accomplish a present position are accessed by the FIX .xed function key, and are described below (Figure 3-22). Doppler up-
dates are done in two steps. The .rst step, performed by pressing the MARK soft key, tells the Doppler to prepare for the landmark update. Upon receipt of this message, the Doppler marks its internal position. The second step, per-formed by pressing the ACC soft key on the DELTAS screen, tells the Doppler the correct position at the time when the .rst message was sent. Doppler then calculates the difference between the correct position and its marked position, and then applies that correction to the Doppler current position.
3.13.2.2.1 Fix Menu Screen.
CONTROL/ FUNCTION
INDICATOR
FIX MENU Title of screen.
UPDATE Access FLYOVER UPDATE
sFLYOVER screen.
STORE Access FLYOVER STORE
FLYOVERg screen.
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3.13.2.2.2 Flyover Update Screen. Use this screen to designate a known position as a update waypoint, as the helicopter .ies directly overhead.
CONTROL/ INDICATOR FUNCTION
WPT Used to enter the waypoint number. The name will be displayed automatically.
LAT/LONG Displays coordinate waypoint. of selected
MARK Initiates update, causes position to be transferred to DELTAS screen, where difference between the Flyover position and Doppler position is displayed.
MGRS Toggles between MGRS and LAT/ LONG coordinate format.
RTN Access screen. previously displayed
3.13.2.2.3 DELTAS Screen. Use this screen to monitor and complete the Doppler update. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址:UH-60Q 直升机技术手册 直升机操作手册 1(94)