Discussion:
Antenna cable delay compensation
Add Reply
Mark Sims
2018-05-22 02:55:54 UTC
Reply
Permalink
Raw Message
A related question is: Do you use positive or negative numbers to set the antenna cable delay value? Again, most GPS receiver documentation does not say. I think that I've only seen it explicitly mentioned in the Trimble documentation and the Oscilloquartz Star-4 documentation.

Also there is the question of does the receiver time message come out before or after the 1PPS and what is the message offset time from the 1PPS? Again, rarely documented by the receiver manufacturer. Lady Heather can measure those (if the operating system clock is accurately set) Heather uses the message time offset to adjust the displayed time or get the audible "tick clock" aligned to true time.

Heather has a table of typical message offsets for the supported receivers, but measuring and setting the value for your receiver/computer/serial port can improve things.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Azelio Boriani
2018-05-22 12:09:25 UTC
Reply
Permalink
Raw Message
In the uBlox protocol specifications there is an antCableDelay, an
rfGroupDelay, a userConfigDelay, all are 2's complement quantities, no
bounds given in the manual.
Post by Mark Sims
A related question is: Do you use positive or negative numbers to set the antenna cable delay value? Again, most GPS receiver documentation does not say. I think that I've only seen it explicitly mentioned in the Trimble documentation and the Oscilloquartz Star-4 documentation.
Also there is the question of does the receiver time message come out before or after the 1PPS and what is the message offset time from the 1PPS? Again, rarely documented by the receiver manufacturer. Lady Heather can measure those (if the operating system clock is accurately set) Heather uses the message time offset to adjust the displayed time or get the audible "tick clock" aligned to true time.
Heather has a table of typical message offsets for the supported receivers, but measuring and setting the value for your receiver/computer/serial port can improve things.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-***@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Loading...