navigation acronyms, abbreviations and definitions - International ...

WSO Weapons Systems Officer
WSSE weighted sum of squared errors
WT water track (path of ship’s movement through the water)
WT watertight
WTA Wireless Telegraphy Act (UK)
WTEMP water temperature
WUL worst user location (integrity chack)
WV water vapour
WWAN wireless wide area network
WWNWS World-Wide Navigational Warning Service (IMO & IHO)
WWRNS World-wide Radionavigation System
Described in IMO Res. A.815(19).
www World-wide Web (Internet)
Wx weather
WX NIL no significant weather
WYSIWYG what you see is what you get
X-112 extended emergency phone call giving data alongside voice call
X-band Old radar band 8-12 GHz (ITU assigned 8,500-10,680 MHz) ~ 3 cm
XAL HAL or VAL
XGA Standard display format of 1,024 x 768 pixels
XLRP XML location reporting protocol
XML Extensible Mark-up Language (complements HTML)
XTD cross-track distance (perpendicular to ground track)
XTE cross-track error (perpendicular to ground track)
Y-Code (P(Y)) encrypted P-Code (comprises modulo-2 addition of P-Code & W-Code)
Y2K Year 2000
Y2Y year-to-year
YAH You are here (maps for pedestrians)
Z zenith (point on the celestial sphere vertically overhead)
Z-Count Fundamental GPS time unit
A 29-bit binary number of which 10 most significant bits give GPS
week number and 19 least significant give time-of-week (TOW) count in
units of 1.5 seconds. Truncated TOW in 6-sec epochs included in
navigation message HOW.
ZD zone description
ZigBee standards-based wireless networking system
ZLG Zero-Lock Laser Gyro (2 laser gyros in one - Northrop Grumman)
ZT zone time
The local mean time of a reference or zone meridian, whose time is
kept throughout a designated zone. The zone meridian is usually the
nearest meridian whose longitude is exactly divisible by 15 º.
ZTD zenith tropospheric delay
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