PPS Source (Non-GPS)

A non-GPS PPS Source, such as a radio, may also be used for clock timing. It cannot be used for synchronization since there is no time data, but it can be used to ensure a clock ticks accurately.

PPS Source Settings

Serial Port:

All serial ports detected on the firewall are listed. Select the port with the GPS attached. On-board hardware serial ports start with cuau, USB serial ports are prefixed with cuaU.

Fudge Time 1:

Specifies a constant to be added to the PPS signal as an offset, to account for delay between the transmitter and receiver.

Stratum:

Used to configure the stratum of the PPS source. The default value is 0 so the PPS source is preferred over all others. If another clock must be preferred instead, set the stratum value higher than the stratum of the preferred clock.

Flags:
Falling edge PPS signal processing:

When set, the falling edge of the PPS signal is used for timing, rather than the rising edge.

Kernel PPS clock discipline:

When set, the OS Kernel will use PPS directly for timing.

Record a timestamp:

Record a timestamp once for each second, which is useful for constructing Allan deviation plots.

Clock ID:

A 1-4 character identifier used to change the PPS Clock ID. The default value is PPS.

Configure a PPS Source

To configure a Non-GPS PPS source:

  • Navigate to Services > NTP

  • Click the PPS tab

  • Configure the settings

  • Click Save