A native Windows application for receiving, decoding and visualising Iridium satellite signals. Load an IQ recording or plug in an SDR, and IridiScope shows a live spectrum and waterfall, demodulates Iridium bursts, parses the messages, decodes voice calls, reassembles ACARS/SBD traffic, and plots the satellites on a world map.

Download the official Windows builds from https://sarahsforge.dev/products/iridiscope.

Builds published anywhere else are not official.

• Live spectrum + scrolling waterfall with configurable FFT size and averaging.
• Full Iridium burst detection, DQPSK demodulation and native message parser (IRA, IBC, IDA, IMS, ITL, SY, IP, VO).
• Satellite tracking and ring-alert positions on an equirectangular world map.
• Voice call capture with in-app playback, plus ACARS/SBD message decoding.
• Sources: IQ file, SDRplay, HackRF and Airspy (all locked to the Iridium band at 1623.326935 MHz), with gain and bias-tee controls.
• Automatic update notifications.

Requirements: Windows, MSYS2 with the mingw-w64 toolchain, CMake and Ninja, and PowerShell.

# from the repository root
powershell -ExecutionPolicy Bypass -File scripts\bootstrap.ps1   # build the vendored FFTW
powershell -ExecutionPolicy Bypass -File scripts\build.ps1

The executable is produced at build\IridiScope.exe. SDR support is detected automatically at configure time; if the SDRplay API, libhackrf or libairspy are not found, that source is simply disabled.

Handy headless modes: --info <file>, --scan <file> [seconds], --sdr-list, --hrf-list, --ap-list, --check-update.

Requirements: Xcode command-line tools and Homebrew. For SDRplay devices, also install the SDRplay API for macOS.

bash scripts/build_macos.sh
open build-macos/IridiScope.app

The script installs CMake, Ninja, FFTW, libhackrf, libairspy and librtlsdr from Homebrew and builds build-macos/IridiScope.app with the NEON DSP kernels on Apple Silicon. When started from Finder, the window layout and voice recordings are kept in ~/Library/Application Support/IridiScope.

sudo apt install cmake ninja-build libfftw3-dev libcurl4-openssl-dev \
  libgl-dev libx11-dev libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev \
  libwayland-dev libxkbcommon-dev wayland-protocols \
  libhackrf-dev libairspy-dev librtlsdr-dev zenity
cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build && ./build/IridiScope

On macOS and Linux the update check and aircraft lookup use libcurl, and the file dialogs use the system picker (AppleScript on macOS, zenity or kdialog on Linux).

IridiScope is built on the work of others:

• iridium-sniffer (muccc) — burst detection and demodulation core.
• iridium-toolkit (Sec, schneider) — message-format reference.
• osmo-ir77 (Sylvain Munaut / Osmocom) — Iridium AMBE voice vocoder.
• Dear ImGui (Omar Cornut) and ImPlot (Evan Pezent).
• GLFW, FFTW, miniaudio, stb.
• SDR backends: SDRplay API, libhackrf (Great Scott Gadgets), libairspy (Airspy).

SDR integration was modelled on AirScope. Map imagery courtesy of NASA.

Released under the GNU General Public License v3.0.