Roger Oberholtzer wrote:
The values are over a serial port. These are high-end Trimble receivers. The reason for the serial port is that there is a pulse-per-second signal that tells when certain calculations in the receiver were done. We are striving for sub-meter accuracy in a vehicle traveling up to 110 km/h. Any transmission delay from when something is calculated to when it is received is a source of error. The pps signal helps eliminate this.
gpsd appears to know about PPS signals.
I would be very happy if there was an ethernet or usb receiver that still had all these features. Unfortunately, they typically are geared for less demanding location requirements and so do not provide these extra signals. We keep looking and hoping. There are some PCI-based models that look interesting.
The gpsd man page has a section on 'use with ntp', for example.
I would be happy if the ntp daemon could be told when to use the receiver, and when not to use it. But I do not think this is the way it is. The GPS will give bad/old/misc times when there are no receivers. Like in a garage. Which is where the measurement systems often are started.
So the GPS is connected to your software and that is deciding whether the signals are good? So why not set the system time from your software, either by starting and stopping ntpd appropriately or by directly setting the time? Cheers, Dave -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org