4 Operation and Performance
6 0 Lassen SQ GPS Receiver
There are also two time coordinate systems:
•
GPS time — GPS time is determined by an ensemble of atomic
clocks operated by the Department of Defense (DOD).
•
UTC time — UTC time is the world standard maintained by an
ensemble of atomic clocks operated by government
organizations around the world. UTC time replaced GMT
(Greenwitch Mean Time) as the world standard, in 1986.
GPS time is steered relative to Universal Coordinated Time (UTC).
GPS does not recognize leap seconds resulting in a situation where
GPS time is currently 13 seconds ahead of UTC time. Time tags for
most output messages can be in either UTC time or GPS time, as
chosen by TSIP command 0x35.
4.7.2
NMEA 0183
The NMEA 0183 protocol only supports LLA format and UTC time.
Velocity is always described as horizontal speed and heading; vertical
speed is not output.
Summary of Contents for SQ
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Page 12: ...Contents xii Lassen SQ GPS Receiver...
Page 14: ...About this Manual xiv Lassen SQ GPS Receiver...
Page 46: ...2 Hardware Integration 32 Lassen SQ GPS Receiver...
Page 150: ...B TSIP Tool kit User s Guide 136 Lassen SQ GPS Receiver...
Page 166: ...C NMEA 0183 152 Lassen SQ GPS Receiver...
Page 171: ...Lassen SQ GPS Receiver 157 Specifications and Mechanical Drawings D...
Page 175: ...Lassen SQ GPS Receiver 161 Specifications and Mechanical Drawings D...
Page 179: ...Lassen SQ GPS Receiver 165 Specifications and Mechanical Drawings D...
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Page 182: ...D Specifications and Mechanical Drawings 168 Lassen SQ GPS Receiver...