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APRS Format

Basic APRS Format Reference

  • '|' - Longitude least significant digits
  • '_' - Latitude least significant digits
  • 't9' - Master motherboard PCB temperature
  • 's' - Satellites in view
  • 'h' - Horizontal dilution of precision

Detailed APRS Format Reference

APRS comment fields contain serialized data in a custom format. Data is arranged in a serialized string with identifiers separated by tiledas. A sample comment is provided below:


Each identifier is outlined in the list below. Note that identifiers with asterisks include one decimal digit after the identifier. This digit designates which node in the network this reading came from. For instance, the master module is always identified as 9. Therefore, in the above sentence, “t911” denotes a board temperature for the master module of 11 degrees celsius.

Module Data Type Identifier
Board Temperature (C) t*
Battery Level (V) l*
Info Message i
Latitude least-significant digits _
Longitude least-significant digits |
HDOP (meters) h
Velocity (knots) v
GPS satellites in view s
Air Temperature (C) C
Ambient Light (Lux) L
Relative Humidity (% RH) H
Pressure (kPa) H
Altitude (m) A
Radiation (CPM) R
opentrack/aprs_format.txt · Last modified: 2019/06/13 02:48 (external edit)