linux-tools - Güralp Systems Ltd

Güralp Systems Linux tools
If required, the PPS signal can be inverted. This would require the
configuration variable invert_pps = true.
5.3.3 NMEA sentence configuration
The latitude, longitude, height and geoid variables may be set to alter
various parts of the NMEA sent string to the instrument. This is
optional but potentially useful to keep diagnostic log messages intact.
These take the following format:
• latitude: 4807.0380,N (48° 07.0380' North)
• longitude: 01131.0000,E (11° 31.0000' East)
• height: 00054 (54m above sea level)
• nmea_geoid: 047 (geoid (the height of sea level above WGS-84
ellipse) of 47m)
5.3.4 NTP configuration
The ntp_max_error variable may be set to change the sensitivity of
the system to NTP. This is a value in microseconds (µs) which sets the
threshold of when the NMEA output says “GPS time locked” and when
it says “GPS time unlocked”. If the system's estimated NTP error
exceeds this value, the NMEA output is unlocked.
It is possible to test the value of this and tune it by switching on
debugging messages (log_level = LOG_DEBUG).
5.4 cd11-test-recv
5.4.1 Logging
The configuration file of the test receiver is a plain text file containing
a set of lines in the format name = value. A # character may be used
to mark the rest of the line as a comment. Comments and blank lines
are ignored.
Unless overridden with the ­s command-line switch, ntp-to-nmea will
by default log to the system log (syslog). By default the application
will use a syslog tag based on the name of its configuration file, e.g.
“ntp-to-nmea[test]”. This can be overridden by changing the
log_name variable.
The level of messages which can be logged is set by the log_level
variable which may take values LOG_DEBUG (which includes
30 Issue E