USB GPS with PPS and pretty cheap too - Server operators - NTP Pool Project
Navilock Products 62530 Navilock NL-8222MP MD6 Serial PPS Multi GNSS Receiver u-blox 8 10 m
GitHub - ddrown/usb-gps: Stratum 1 NTP setup using USB to transfer GPS PPS info
DIYmalls VK-162 G-mouse USB GPS Dongle Track Navigation Receiver Module Support Raspberri Pi Linux Window Google Earth, not compatible with IOS Andriod : Amazon.co.uk: Computers & Accessories
z052 USB GNSS Dongle with PPS
Adding PPS to a cheap USB GPS stick | Brendan's Radio Blog
VK-162 USB GPS Dongle G-Mouse G7020 Channels U BX M8030 Chip For doogle Earth | eBay
VK-172 GMOUSE USB GPS Module GLONASS USB GPS Interface Navigation For Car/Vehicle OEM/Wholesale/Drop - V.KEL Communications Equipment(SHENZHEN) Co.,Ltd
Amazon.com: ICP DAS GPS-721 GPS Receiver and 1 DO, 1 PPS Output Module communicable Over RS-232 and RS-485. : Electronics
Setting Everything Up | Adafruit Ultimate GPS with gpsd | Adafruit Learning System
USB Level GPS Module + Antenna Integrated Module Receiver PPS Second Pulse Timing BS 506C|Cable Winder| - AliExpress
Amazon.com: Stemedu USB GPS Module GLONASS Beidou UBX-M8030-KT GPS Dongle Built-in Ceramic Antenna for Ar-duino Pixhawk Stratux, Better Than VK-162 VK-172 : Electronics
Time Server
Usb Gps Module Beidou Satellite Receiver External Module Road Test Network Optimization Pps Timing Strong Waterproof - Cable Winder - AliExpress
USB GPS Receiver GPS/GLONASS Navigation and Tracking Wiki - DFRobot
Raspberry Pi GPS Module USB Port – Kuongshun Electronic Shop
USB GPS Module – ODROID
So you want a Stratum 1 NTP server...
How to use GPS module for real-time location and PPS clock synchronization service
Microsecond accurate NTP with a Raspberry Pi and PPS GPS - Austin's Nerdy Things
