MerABoire is a collection of tools to assist the listener to decode and (hopefully) make sense of VHF ACARS broadcasts. It requires UNIX (currently FreeBSD), a soundcard and a VHF AM receiver.
To the best of my knowledge, it is the first open source implementation. Shareware and freeware alternatives are Windows only and don't run at all on modern hardware (KRACARS), or have a pretty poor record in decoding packets off the wire (WACARS). Commercial implementations include WinRadio.com's advanced data suite, and the Skysweeper suite.
On my home systems, MerABoire is more successful in decoding packets than WACARS or the SkySweeper suite. I can only hope the code will pass expert analysis though; I'm not a DSP designer by trade. Needless to say, some of the code is extremely hackish.
The package consists of a daemon to demultiplex the stereo audio stream into two seperate mono streams to allow two radios to be hooked to one computer; tools to decode audio streams or .wav snippets into binary data records, tools to display the binary records; and tools to import those records into a MySQL database and search them using a Web interface. I don't think I duplicated any existing functionality; but if I did I want to know about it!
Now that another tool for dealing with ACARS records is available I will happily defer to that project to make a GUI and do something about maintaining tables and stuff. It turns out not to be Open Source, but it seems to be pretty good: acarsd.org.
All tools mentioned are coded up and are in use on a handful of sites. As the code stands, it could do with a cleanup, packaging etcetera. That said, the code has been independantly installed successfully, so this is not vaporware.
I do not foresee this becoming production quality code any day soon. However, as the old saying goes: we're taking patches!
For the terminally curious: MerABoire derives its name from a French band called Les Negresses Vertes. I found myself one night, looking at WACARS and thinking: what would it take to do something like this myself? I've got to learn about DSP. I've got to learn about recording stuff with a soundcard on UNIX. I've got to figure out what people mean when they say that ARINC did something weird with the CRC. How is MSK different from FSK? And if I got the packets to decode, what would I do with them? I'll need a GUI, and a database. That's going to be a lot of code, a lot of learning, a lot of time. It sounded big. It didn't sound possible. And then Les Negresses Vertes reminded me of a French saying: "c'est pas la mer à boire" -- "It's not like having to drink the sea". Not that it helped the main character of that song.
MerABoire is dedicated to all who intentionally stray off the path of wisdom and achievable goals.
Bert Driehuis, Leiden, The Netherlands.