zig1090

Standalone ADS-B / Mode S demodulator in Zig with an optional web map (Leaflet + /aircraft.json) and dump1090-style TCP feeds. RTL-SDR IQ uses librtlsdr with a small ring buffer.

License: MIT.

Build

Prerequisites

• Zig: 0.15.0 or newer.

• RTL-SDR drivers and librtlsdr dev package:

  • Linux (Debian/Ubuntu):

    sudo apt-get update
    sudo apt-get install -y librtlsdr-dev libusb-1.0-0-dev

  • macOS (Homebrew):

    brew update
    brew install librtlsdr

  • Windows (example: vcpkg):

    git clone https://github.com/microsoft/vcpkg.git
    .\vcpkg\bootstrap-vcpkg.bat
    .\vcpkg\vcpkg install rtlsdr:x64-windows

    Point Zig at the installed include/lib paths if needed (e.g. INCLUDE / LIB on Windows).

Build

cd zig1090
zig build

Run

Defaults: center 1090e6 Hz, sample rate 2.0e6 Hz. Optional positionals override center and rate.

Basic

zig build run

Receiver position (CPR reference)

zig build run -- --lat 39.528 --lon -119.815

Web map (example: Reno, NV)

zig build run -- --http 8080 --lat 39.528 --lon -119.815

Open http://127.0.0.1:8080/.

dump1090-style TCP (--net)

Default listen ports match FlightAware dump1090 (applyNetDefaults):

Port	Role
30002	Raw: *<hex>;\n
30003	BaseStation (SBS)
30005	Beast cooked binary

zig build run -- --net --lat 39.528 --lon -119.815

• --net-bind-address <ip> — default 0.0.0.0.
• --net-ro-port, --net-sbs-port, --net-bo-port — overrides (any of these enables --net).
• --net-heartbeat <seconds> — keepalives (default 60, 0 = off).

Beast cooked skips 2-bit CRC–repaired frames. Raw input (30001), Beast input (30004), and Stratux output are not implemented yet.

Acknowledgments

• ZigRadio — src/rtl_iq.zig follows its RTL-SDR IQ scaling and device setup (upstream: Ivan A. Sergeev).
• ICAO ADS-B / Mode S — CPR math in src/adsb/cpr_decode.zig follows the published standard.
• dump1090 / readsb — de-facto Mode S message layout and CRC behavior for interoperability.
• Maps — OpenStreetMap & CARTO tiles; Leaflet.

Provenance

• This codebase is an independent Zig implementation of publicly documented ADS-B / Mode S behavior (ICAO Annex 10 and DO-260 family conventions).
• References to dump1090/readsb are interoperability notes and naming comparisons, not copied source.
• See THIRD_PARTY_NOTICES.md for third-party attribution and bundled-asset licensing notes.

Notes

• ADS-B on 1090 MHz is public signaling; “decoding” here means parsing the ME field.
• Sample rates from ~1.8e6 Hz work for Manchester timing; 2.0e6, 2.4e6, 4.0e6 are common RTL-SDR choices.