pyobelix

Pure-Python decoder for EUROCONTROL ASTERIX surveillance data. Sibling library to pyModeS for Mode-S / ADS-B decoding.

Install

pip install "pyobelix>=0.1"

Python 3.11+ required. Zero runtime dependencies.

Quick start

from pyobelix import iter_records

for rec in iter_records("path/to/asterix.bin"):
    if rec.cat == 48 and "rho" in rec:
        print(rec["icao"], rec["rho"], rec["theta"])

Accepts file paths, bytes/bytearray, or any BinaryIO stream.

Streaming from a socket

from pyobelix import AsterixDecoder

dec = AsterixDecoder()
while True:
    chunk = sock.recv(4096)
    if not chunk:
        break
    dec.feed(chunk)
    for rec in dec.records():
        process(rec)

Decoding Mode-S Comm-B (MB) with pyModeS

pyobelix emits CAT 048 I/250 MB payloads as opaque 14-char uppercase hex strings. To decode the Mode-S fields:

import pyModeS
from pyobelix import iter_records

for rec in iter_records(path):
    if rec.cat != 48:
        continue
    for mb in rec.get("mode_s_mb", []):
        decoded = pyModeS.Message.from_payload(
            mb["mb"], df=20, icao=rec["icao"]
        ).decode()
        print(decoded)

See docs/pymodes-bridge.md for the full recipe.

Supported categories (v.0.1.0)

• CAT 048 — Monoradar Target Reports (EUROCONTROL-SPEC-0149-4 Ed. 1.32)
• CAT 034 — Monoradar Service Messages (EUROCONTROL-SPEC-0149-2B Ed. 1.29)

Additional categories (021, 062, …) planned for v.0.2.0. See the design spec for the full roadmap.

License

MIT. See LICENSE.