mjhjmtu

I can't really figure out how GPSD works. If I start gpsmon nothing happens. But if I run sudo killall gpsd immediately position starts to appear on screen.

The same happens in my node app. I start receiving position as soon as I kill gpsd (after starting my program).

I'm using Garmin USB GPS 18x and a Jetson TX2 on Node v8.11.3. In my program I'm using node-gpsd to handle the GPS data.

The gpsd deamon reads out the GPS-data coming via the serial interface and provides them to other applications via a socket on a specific port (default: port 2947).

The client program gpsmon can be run in one of two modes.

• as a client for gpsd using the socket provided by gpsd
  


• in direct mode, reading out the data coming from the serial interface of the GPS device

Which of both modes you use is determined, with which arguments you start gpsmon.
I don't know, how you start gpsmon, but judging by your description, I assume you start gpsmon in direct mode and therefore only see data, once you kill gpsd and have gpsmon access the serial interface, which was before used by gpsd.

In order to use gpsmon as client for gpsd, please refer to the official documentation of gpsmon.

Regarding your node app:

It's just a guess, but I assume this app is not using the socket provided by gpsd, but wants to listen on the serial interface directly. Thus the behaviour you observe.