Pulse-per-second signal
A Pulse per second (PPS) is an electrical signal emitted by some models of GPS receivers that very precisely indicates the start of a second.
Uses
Because GPS is considered a stratum-0 source, a common use for the PPS signal is to connect it to a PC using a low-latency, low-jitter wire connection and allow an NTP program to synchronize to it: this makes the PC a stratum-1 time source. Note that because the PPS signal does not specify the time, but merely the start of a second, one must combine the PPS functionality with another time source that provides the full date and time in order to ascertain the time both accurately and precisely.
External links
GPS receivers that provide a PPS signal:
- Garmin GPS 18, LVC (barewire) edition only. Offered in 1-Hz and 5-Hz formats.
Sites that describe how to use the PPS signal to set precise time on a PC: