# Local GPS NTP Time Server
Accessible at: 192.168.1.12
Project files stored here: “\\\\192.168.1.11\\zfs\_mirror3\\Projects\\Dormant\\NTP Raspberry Pi Server”
## Build Data
Runs Raspian on a Raspberry PI
Static IP Address was set in: /etc/dhcpcd.conf
[](https://wiki.galaxydump.com/uploads/images/gallery/2025-09/t3CNG2dvgpGka2lO-image.png)
Installed ntpstat with this:
```bash
sudo apt install ntpstat
```
## Usage
Here's some descriptions of the different tools for administrating NTP.
#### NTPSTAT
Use ntpstat to check if the NTP service is in sync:
```bash
ntpstat
```
It will return something like this:
```
synchronised to NTP server (149.20.54.20) at stratum 3
time correct to within 42 ms
polling server every 1024 s
```
For our local NTP server (with GPS receiver), we see this:
```bash
pi@raspberrypi:~ $ ntpstat
synchronised to UHF radio at stratum 1
time correct to within 2 ms
polling server every 64 s
```
The ntpstat utility also returns an exit status, as a quick tell of synchronization.
Use this, following a call to ntpstat:
```
echo $?
```
The return value will mean one of these:
- If exit status 0 – Clock is synchronised.
- exit status 1 – Clock is not synchronised.
- exit status 2 – If clock state is indeterminant, for example if ntpd is not contactable.
#### NTPQ
Use ntpq -p to see the following:
[](https://wiki.galaxydump.com/uploads/images/gallery/2025-09/AgQlX6XhmF1rhxwg-image.png)
#### PPTSTEST
Use this to test the pps signal:
sudo ppstest /dev/pps0
The output should spit out a new line every second that looks something like this (your output will be a bit farther from x.000000 since it isn’t yet using the GPS PPS):
[](https://wiki.galaxydump.com/uploads/images/gallery/2025-09/wReLzudcfng5LRCc-image.png)
#### GPSMON
Use the gps monitor function to check the realtime availability of GPS and satelite count and position, with this:
```bash
gpsmon
```
This will present the following:
[](https://wiki.galaxydump.com/uploads/images/gallery/2025-09/VSVAiDmLXiPfdwjq-image.png)
#### CGPS
Or, using the following for a simpler gps status check:
```bash
cgps
```
This will create the following output:
[](https://wiki.galaxydump.com/uploads/images/gallery/2025-09/gcG0wI1LloRyuDuP-image.png)
### References
How to troubleshoot an NTP server: [https://support.ntp.org/Support/TroubleshootingNTP](https://support.ntp.org/Support/TroubleshootingNTP)
The following link is probably not what was used to build the house time server. But, this is an interesting reference on how to build a Raspberry pi GPS time server:
[Building a Raspberry Pi Stratum 1 NTP Server](https://blog.thelifeofkenneth.com/2020/03/building-raspberry-pi-stratum-1-ntp.html)
Here’s a good reference on how to tune and configure the NTP setup on a RaspBerry PI: [Building a Raspberry-Pi Stratum-1 NTP Server](http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html)
Another reference: [Millisecond accurate Chrony NTP with a USB GPS for $12 USD - Austin's Nerdy Things](https://austinsnerdythings.com/2021/09/29/millisecond-accurate-chrony-ntp-with-a-usb-gps-for-12-usd/)
Good reference on the Shared Memory Driver, and how the 127.127.28.x address is used: [http://doc.ntp.org/archives/drivers/driver28/](http://doc.ntp.org/archives/drivers/driver28/)