Aprs Daemon Configuration Reference

Polaric APRSD is a server program which communicates APRS data with a TNC or APRS-IS or both. It can present and manipulate the information through a simple HTTP service. The daemon can also be set up as an igate (internet gateway) and can run as a standalone program (without the web app component). It can also exchange authenticated messages to propagate updates to other instances over radio or internet.

The configuration files to be edited manually are located in /etc/polaric-aprsd/ The most important one is server.ini. We describe the options in detail below.

This file is the main setup, and it may be adapted to the individual installation. It is a Java «properties» file consisting of name-value pairs. Comment lines start with '#'. The tables below shows all properties which may be set in this file along with the default value and an explanation.

Some of the properties can also be set in another file: /var/lib/polaric/config.xml. This is meant to be used by the web interface and should normally not be edited by hand. The property values here will override the values defined in server.ini. This means that if the web-interface for configuration is used, the values defined in server.ini are then just default values. Properties that is set by the web interface is written in blue italic fonts here. The properties set in the web interface are usually sufficient for getting the server running. The other properties are meant for advanced users.

Polaric APRSD can be given a position and it can be set up to send APRS position reports. Positions can be seen and set through the webapp and a default position can be set in the configuration file.

It can do real GPS tracking with smart beaconing. A GPS can also be used to adjust the computer clock. The tracker has a time-resolution of 10 seconds when it comes to APRS reporting. This means that it decides every 10 seconds if a packet should be sent. The time resolution is also 10 seconds when updating the webapp-display. Internally, however, resolution can be somewhat finer (GPS is read typically every 5 seconds) and note that time parameters are given in seconds and these do not need to be a multiple of 10.

Polaric APRSD kan connect to an APRS-IS server of choice. You can configure host, port, username, passcode and you can set filters (compatible with javaprssrvr). It is also possible to use Polaric APRSD as an igate (gateway between internet and RF). When activating the igate, you should obviously activate both the TNC channel (see below) and the internet channel.

Polaric APRSD implements the APRS messaging protocol and supports igating of messages. Polaric APRSD use messaging internally for remote control, i.e. different instances of the server can be linked such that local changes to icons or station/object aliases are automatically propagated to the other servers. Servers are linked in a hierarchy, i.e. a server can specify a parent server. A parent may have several “children”. Messages are authenticated, i.e. messages have a message-authentication field, which in essence is a MD5 hash of the message plus a secret shared key. See more info about the remote control protocol.

Polaric APRSD can set up a number of channels for position data (mainly APRS).

Config files which defines properties put here will be automatically run after server.ini. Useful for plugins.

Commands to be sent to TNC when starting. Lines starting with # are comments.

An APRS symbol may correspond to an icon (graphic symbol) to be placed on the map. In Polaric Server we may use slightly bigger icons than most other APRS programs. The size is 22×22 pixels. Icons are placed in the subdirectory '/usr/share/polaric/icons'. The file '/etc/polaric-aprsd/symbols' defines a mapping between APRS symbols (two characters: symbol table and symbol code) and a corresponding icon file. Note that we in this file can use regular expressions to match symbols.

This is optional and can be used to define simple, static geographical objects to be placed on the map. Note that these are not APRS objects and are therefore local to the server instance. For each object, define the position (UTM), what map-scales in which to display the object, a URL (or '-' if no URL), an icon (I recommend to use smaller icons placed in the directory 'icons/signs') and a short text.

A simple setup of colours combinations to be used for trails.

This is a script where we set up filters on what to show on the map and how to show it. Filters can be based on tags and other attributes of point objects, etc.. See documentation on the filter script language here.