Menhir

ASTERIX encode/decode workbench for Air Traffic Management engineers

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Menhir is a desktop application built on top of ASTERIXCodec. It provides a Wireshark-style interface for visually inspecting ASTERIX surveillance frames and manually crafting new ones.

Features

Decode mode

• Open a binary ASTERIX file via drag-and-drop, the toolbar, or Ctrl+O
• Type or paste raw hex bytes directly in the interactive hex editor
• Hit F5 (or wait for the auto-decode timer) to get a fully annotated field tree
• Each Data Item is color-coded — clicking a tree node scrolls to and highlights the corresponding bytes in the hex editor, and moving the cursor in the hex editor synchronises the tree selection

Encode mode

• Select a category and UAP variation from the toolbar
• Fill in the structured form; the encoded output updates live as you type
• Copy the result as a hex string with one click

Hex editor

• Type hex digits directly at the cursor — no separate text field
• Navigate with arrow keys, Home, End, Page Up/Down
• Backspace undoes the last nibble or deletes the previous byte; Delete removes the byte at the cursor
• Color-coded byte ranges for at-a-glance attribution

In action

Decode mode — annotated field tree synchronized with the hex editor

Encode mode — structured form with live hex output

Supported categories

Category	Description	Edition
CAT001	Transmission of Monoradar Data Target Reports	1.4
CAT002	Transmission of Monoradar Service Messages	1.2
CAT004	Safety Net Messages	1.13
CAT007	Transmission of Directed Interrogation Messages	1.12
CAT008	Monoradar Derived Weather Information	1.3
CAT009	Composite Weather Reports	2.1
CAT010	Transmission of Monosensor Surface Movement Data	1.1
CAT011	Transmission of A-SMGCS Data	1.3
CAT015	Independent Non-Cooperative Surveillance System Target Reports	1.2
CAT016	Transmission of Data Link Flight Messages	1.0
CAT017	Mode S Surveillance Coordination Function Messages	1.3
CAT018	Mode S Datalink Function Messages	1.8
CAT019	Multilateration System Status Messages	1.3
CAT020	Multilateration Target Reports	1.11
CAT021	ADS-B Target Reports	2.7
CAT023	CNS/ATM Ground Station and Service Status Reports	1.3
CAT025	CNS/ATM Ground System Status Reports	1.6
CAT032	Miniplan Reports to an SDPS	1.2
CAT034	Transmission of Monoradar Service Messages	1.29
CAT048	Monoradar Target Reports	1.32
CAT062	SDPS Track Messages	1.21
CAT063	Sensor Status Reports	1.7
CAT065	SDPS Service Status Reports	1.6
CAT150	MADAP Plan Server - Flight Data Message	3.0
CAT205	Radio Direction Finder Reports	1.0
CAT240	Radar Video Transmission	1.3
CAT247	Version Number Exchange	1.3

Requirements

Dependency	Version
CMake	≥ 3.21
Qt	6.x (Widgets module)
C++ compiler	C++20 (GCC 12+, Clang 15+, MSVC 2022+)

Build

git clone https://github.com/nathan-casabieille/Menhir.git
cd Menhir
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc)

CMake fetches ASTERIXCodec automatically — no manual dependency step required.

macOS

open build/Menhir.app

Linux

./build/Menhir

Windows

.\build\Release\Menhir.exe

Project structure

Menhir/
├── CMakeLists.txt                  # FetchContent pulls ASTERIXCodec automatically
├── src/
│   ├── main.cpp                    # App entry point, palette and stylesheet setup
│   ├── MainWindow.{hpp,cpp}        # Top-level window, toolbar, Decode/Encode mode switch
│   ├── DecodeView.{hpp,cpp}        # Wireshark-style tree + hex editor (decode mode)
│   ├── EncodePanel.{hpp,cpp}       # Structured form + live hex output (encode mode)
│   ├── HexEditor.{hpp,cpp}         # Custom interactive hex editor widget
│   ├── ByteTracker.{hpp,cpp}       # Maps decoded items to byte ranges in the raw buffer
│   └── Theme.hpp                   # Qt stylesheet, item colors
├── specs/
│   └── CAT*.xml                    # 27 ASTERIX category definitions (CAT001–CAT247)
└── resources/
    ├── specs.qrc                   # Embeds XML specs and icons at compile time
    ├── check.svg                   # Checkbox checkmark icon
    ├── menhir-icon.png             # Application icon (source)
    ├── menhir.icns                 # macOS bundle icon
    └── menhir.ico                  # Windows executable icon