GPS (gpsd)

A GPS receiver gives hamstack your grid square, so a portable station does not need it typed in at each site, and gives Pat a position for its position reports. gpsd owns the receiver and shares it with every program that wants a position; hamstack runs one as a user service next to the others.

hamstack install gpsd              # the distribution's package (not built from source)
hamstack gps use                   # finds a receiver that is plugged in (u-blox and Garmin are recognised)
hamstack gps use /dev/serial/by-id/...   # any other receiver: name it
hamstack units install && hamstack start gpsd
hamstack gps                       # service state, fix, satellites in use, position and grid
hamstack gps grid                  # wait for a fix and print your grid square
hamstack gps grid --save           # ... and save it for the current site (then: hamstack pat locator)
hamstack gps use --addr HOST:PORT  # use a gpsd that already runs (a system gpsd, or another machine's)
hamstack gps on|off|remove

hamstack’s gpsd listens on port 2948 on this machine only, not gpsd’s standard 2947, so a system-wide gpsd cannot clash with it. The receiver is found again by its USB identity when you replug it, like a radio. It is started read-only (-b): gpsd normally probes a receiver by sending it commands, and a device chosen by mistake (a radio’s CAT port) must not be sent anything; gps use also refuses a port that a rig already uses. pat sync points Pat’s gpsd setting at it (only the address; Pat’s own switches stay as you set them). hamstack doctor checks that gpsd is installed, the receiver is there and readable, and that it has a fix.

Debian and Ubuntu: the gpsd package also starts a system-wide gpsd (gpsd.socket) and a udev rule that hands GPS receivers to it as they are plugged in. That gpsd then holds the receiver, and hamstack’s cannot open it. hamstack doctor warns when it is running; turn it off with sudo systemctl disable --now gpsd.socket gpsd.service. Time synchronisation from GPS (chrony) is not set up: it needs system-wide configuration.

Tested with a simulated receiver (NMEA written into a pseudo-terminal, read by a real gpsd under systemd on Debian, Fedora and Arch). Not tested with a real receiver, so receiver recognition, the udev interplay above and a cold start on a real device are unverified.