The reference basestation is based on a Raspberry Pi 3 and a u-blox M8T receiver. The basestation is configured as an NTP server, RTKlib rtkrcv for location and a combination of RTKlib str2str and PylonGPS transceiver for data streaming.
The Raspberry Pi 3 is connected to the M8T receiver via USB for data and GPIO pin 4 for the 1 Hz PPS signal.
The NTP server is configured as a client to 4 pool.ntp.org servers of the country of the basestations public IP. The M8T PPS signal is provided via the kernel based PPS driver and used by NTPD for precision timekeeping. NTPD is configured as an NTP server for public reuse.
RTKlibs rtkrcv is the direct user of the M8T receiver via its USB based serial tty. rtkrcv continuously computes the basestations location from the satellite data. It is configured to provide several network ports on the local IP:
:3130 - telnet console (-p option) :3134 - monitoring port (-m option)
str2str is used to shield rtkrcv from user acces and convert the u-blox receiver data format into standardised RTCMv3 format.
:3131 - passthrough receiver data / raw (u-blox format) :3132 - passthrough receiver data / RTCM3 :3133 - TCM3 antenna location message 1006 :3141 - integrated RTCM 3 location and raw data