Raspberry Pi 5 synchronized only with PPS acting as PTP timeserver

This repository contains instructions for building a Raspberry Pi 5 PTP timeserver with the following properties:

• Long-term synchronization is based solely on a PPS without any additional information.
• The PPS can be isolated, i.e. without synchronization with a common time standard such as TAI/UTC/GPST. Therefore, the PPS can be provided by any generic signal generator.
• Only during the boot process does the Pi 5 attempt to query public NTP servers for a limited duration to align its system time. After that, the system time only depends on the PPS and may slowly start to deviate from common time standards.
• The use case is a semi-isolated system. It has access to NTP servers synchronized with UTC, but no access to a PTP master or any precise hardware reference clock synchronized with a common time standard, for instance a GPS-derived PPS due to being indoors.

System Overview

For comparison, a similar system with GPS as the hardware reference clock:

System Overview with GPS

Server

Instructions for the server setup are here.

Client

Instructions for the client setup are here.

Acknowledged

This project is a fork of this repository.

Useful Links

• ptp4l High Values of Master offset freq and path delay
• Creating an isolated NTP server with only 1PPS