This repository contains Octave/MatLab scripts to generate Plain-Old-ACARS (PoA) waveform IQ files with arbitrary message payloads.
PoA is simply a Minimum Shift Keyed envelope wrapped into classic Amplitude Modulation for transmission with generic aviation voice radios. The MSK contains two symbols at 1200 Hz and 2400 Hz respectively, and so delivers 2400 bps.
The AM wrapping is nothing to write home about, it's just classic double sideband AM with a modulation index of 100 %.
Install GNU/Octave or MatLab.
Signal package is required. For Octave, run pkg install -forge signal.
In Octave or Matlab run acarsgen
The script asks to input only the message field of ACARS. A maximum of 220 character is allowed due to protocol limitations. If you want, you can edit the contents of gen_acars_msg_aju1.m to change the other fields to fit your needs.
The script outputs a single file "poa_1M152.cs8" designed for transmission with HackRF One hardware. The file is interleaved signed int8 I and Q channels at a sampling rate of 1 152 000 Hz (or 24×48 000 Hz). The signal is appended with zeroes to make the file exactly one second in length.
The scripts are interdependent in the following order: gen_am_wrap_aju1.m → gen_msk_aju1.m → gen_acars_msg_aju1.m
For SCIENCE!
Disruption of aviation communications will put you to jail. Be smart and do not test your luck.
If you'd like to try reception of your signals, I suggest looking into acarsdec.
MIT license. Read more in LICENSE.md