### GPSDConfig Help

## Configure and monitor GPS Daemon (gpsd)

GPSDConfig will generate and install the files required to launch the gpsd daemon at system boot.

GPSDConfig can also be used to stop/start gpsd at any time.

gpsd will be configured to use the selected GPS Receiver serial device, usually connected via USB.

You can also use GPSDConfig to monitor gpsd running on a remote host that has been configured to allow external monitoring.

#### GPSDConfig Windows

- GPSD Config
- Monitor
- Satellites

#### Pre-requisites

You will need a USB GPS receiver device to plug in to your Mac. These range in price from very cheap (under $10USD) to very expensive and are available at your normal outlets (e.g. Ebay, Amazon, your local computer store etc).

You should have gpsd installed on your system. The simplest way to install gpsd is using the Homebrew package manager as outlined in How to install gpsd

#### Communication between GPSDConfig and gpsd

GPSDConfig operates as a client to a gpsd daemon. The daemon may be running on your local machine or on a remote machine.

The communication protocol used is documented at gpsd_json.

Although it is recommended in the documentation to use the gpsd library `libgps`, that would mean GPSDConfig would have to link against this library, causing all sorts of problems in installing an appropriate version of gpsd on your machine.

If the on-wire protocol is changed by future versions of gpsd then I will attempt to resolve any issues at that time.

#### Integration with chronyd

If chronyd is being used to keep your system clock accurate, then you can use GPSDConfig to configure gpsd to wait for chronyd to start before launching. This delay enables chronyd to begin listening for time information before gpsd attempts to send any.

GPSDConfig will generate a chronyd refclock directive that will enable chronyd to receive time information sent from the Global GPS satellite network via gpsd.

You can copy/paste this directive to your chrony.conf file using the ChronyControl Utility.

NB Pulse Per Second (PPS) time signalling is NOT available as the Darwin kernel used by macOS does not support this protocol.

Copyright © 2023 B.R. Christianson (bryan@whatroute.net)