EndRun RTM3204, Руководство пользователя

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R T M 3 2 0 4 G P S T i m i n g M o d u l e U s e r M a n u a l 20
C H A P T E R T H R E E
21 R T M 3 2 0 4 G P S T i m i n g M o d u l e U s e r M a n u a l
C O N T R O L A N D S T A T U S C O M M A N D S
results of this poll are used to steer the system clock and are saved to a log file. This command parses
and formats the information contained therein and prints this fixed-length string having these fields:
LKSTAT TFOM = ? YEAR DOY HH:MM:SS.sssssssss LS LF S N VCDAC SN.R FLTS
Where:
LKSTAT is the tracking status of the engine, either LOCKED or NOTLKD.
TFOM = ? A detailed explanation of TFOM is in Appendix A - Time Figure-of-Merit .
Briefly, TFOM indicates clock accuracy where:
4 time error is < 1 us
5 time error is < 10 us
6 time error is < 100 us
7 time error is < 1 ms
8 time error is < 10 ms
9 time error is > 10 ms, unsynchronized state if never locked to GPS.
YEAR is the year of the UTC timestamp of the most recent information received from
the GPS subsystem.
DOY is the day-of-year of the UTC timestamp of the most recent information received from
the GPS subsystem..
HH:MM:SS.sssssssss is the hour, minute, second.subsecond UTC timestamp of the most
recent information received from the GPS subsystem.
LS is the current number of leap seconds difference between the UTC and GPS timescales
(13 at the time of this writing).
LF is the future (at the next UTC midnight) number of leap seconds difference between the
UTC and GPS timescales (13 at the time of this writing).
S is the Signal Processor State, one of 0 (Acquiring), 1 (GPS Locking), 2 (GPS Locked).
N is the number of GPS satellites being tracked, 0 to 8.
VCDAC is the 20-bit oscillator Voltage Control DAC word, 0 to 1048575 with larger
numbers implying higher oscillator frequency. Typical range is 320000 to 640000.
SN.R is the carrier Signal to Noise Ratio, 0.00 to 99.9, measured in dB in the GPS data rate
bandwidth. Typical range is 30 to 45.
FLTS is the fault status, which displays the current summary status of the GPS timing
subsystem. The summary status is contained in sixteen bits which are displayed in four
hexadecimal characters. Assertion of any of these bits will also be indicated by
illumination of the red LED. Each bit of each character indicates the status of a
subsystem component: