ardu2igc

Convert ArduPilot .bin flight logs to IGC format — in Python or C#

The universal bridge between ArduPilot telemetry and the FAI/IGC flight recorder standard.
Works with ArduCopter, ArduPlane, and any ArduPilot-based flight controller.

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Why ardu2igc?

ArduPilot is the world's most popular open-source autopilot, powering everything from racing quads to fixed-wing survey aircraft. Its .bin logs contain rich flight data — but they're locked in a proprietary binary format.

IGC is the international standard for flight data validation, used by glider competitions, FAI record claims, and flight analysis tools worldwide.

ardu2igc connects these two worlds. Drop in a .bin file, get a standards-compliant .igc file out. Use it from Python or C# — same algorithm, same output.

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Features

• Dual-language — Pure Python and pure C# implementations with identical behavior
• Zero-dependency C# — No NuGet packages required; reads binary DataFlash directly
• pymavlink-enhanced Python — Uses ArduPilot's own parser when available, standalone fallback when not
• Self-describing parser — Discovers message schemas from FMT records inside each .bin file (works with any ArduPilot version)
• Full IGC compliance — A, H, I, B records with FXA extension per FAI specification
• Smart altitude fusion — Combines barometric and GPS altitude sources with configurable priority
• Flight date extraction — Automatically determines UTC date from GPS week numbers
• Time gap handling — Detects and skips large gaps in telemetry without corrupting output
• CLI tools included — Ready-to-use command-line converters for both languages

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Quick Start

Python

# Install from source
cd ardu2igc/python
pip install -e .

# Convert a log file
ardu2igc flight.bin

# With options
ardu2igc flight.bin -o myflight.igc --pilot "Jane Doe" --glider-type "DJI Mavic 3"

# Inspect a log without converting
ardu2igc flight.bin --info

C#

# Build
cd ardu2igc/csharp
dotnet build -c Release

# Convert a log file
dotnet run --project Examples -c Release -- flight.bin

# With options
dotnet run --project Examples -c Release -- flight.bin -o myflight.igc --pilot "Jane Doe"

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Usage

Python API

import datetime
from ardu2igc import convert, ConversionOptions, IgcWriter, IgcFix

# One-liner conversion
result = convert("flight.bin", "output.igc", ConversionOptions(
    pilot_name="John Doe",
    glider_type="ArduCopter",
    altitude_source="both",
))
print(f"Wrote {result['fixes_written']} fixes")

# Programmatic IGC generation
writer = IgcWriter()
writer.set_header(
    pilot_name="John Doe",
    glider_type="Quadcopter",
    date=datetime.date(2024, 7, 15),
)
writer.add_fix(IgcFix(
    timestamp=datetime.time(14, 30, 0),
    latitude=47.39774,
    longitude=8.54559,
    valid=True,
    pressure_altitude=450,
    gps_altitude=462,
    fix_accuracy=12,
))
writer.write("manual.igc")

C# API

using Ardu2IGC;

// One-liner conversion
var result = ArdupilotConverter.Convert("flight.bin", "output.igc", new ConversionOptions
{
    PilotName = "John Doe",
    GliderType = "ArduCopter",
    AltitudeSource = "both",
});
Console.WriteLine($"Wrote {result.FixesWritten} fixes");

// Programmatic IGC generation
var writer = new IgcWriter();
writer.Header.PilotName = "John Doe";
writer.Header.GliderType = "Quadcopter";
writer.Header.Date = new DateTime(2024, 7, 15);
writer.AddFix(new IgcFix
{
    Timestamp = new DateTime(2000, 1, 1, 14, 30, 0),
    Latitude = 47.39774,
    Longitude = 8.54559,
    Valid = true,
    PressureAltitude = 450,
    GpsAltitude = 462,
    FixAccuracy = 12,
});
writer.Write("manual.igc");

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CLI Reference

Option	Description	Default
-o, --output	Output IGC file path	<input>.igc
--pilot	Pilot name	(empty)
--glider-type	Aircraft type	(empty)
--glider-id	Registration / ID	(empty)
--comp-id	Competition ID	(empty)
--comp-class	Competition class	(empty)
--alt-source	Altitude source: baro, gps, both	both
--max-gap	Max gap between fixes (seconds)	60
--fix-accuracy	Override fix accuracy (meters)	0 (auto)
--gps2	Use GPS2 message instead of GPS	false
--info	Show log info without converting	false
--json	JSON output (with --info)	false

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How It Works

ArduPilot .bin Format

ArduPilot DataFlash logs are self-describing binary files. Each log begins with FMT messages that define the schema for every message type (GPS, BARO, ATT, etc.). This means ardu2igc works with any ArduPilot version without hardcoding message definitions.

[0xa3 0x95] [type_id] [message_data...]

The parser discovers schemas at runtime:

Message	Key Fields
GPS / GPS2	Lat, Lng, Alt, Status, HDop, Week, TimeMS
BARO / BAR2	Alt, TimeMS
FMT	Schema definitions (parsed automatically)

IGC Format

The IGC format is an ASCII-based standard defined by the FAI Gliding Commission. Each file contains:

Record	Purpose
A	Flight recorder identification
H	Header metadata (date, pilot, glider, sensors)
I	Extension definitions for B records
B	GPS fixes (timestamp, lat, lon, altitude, accuracy)

A valid B record looks like:

B1430004723864N00832735EA0045000462012
│      │       │        │ │     │    └── FXA (fix accuracy)
│      │       │        │ │     └─────── GPS altitude
│      │       │        │ └──────────── Pressure altitude
│      │       │        └────────────── Validity (A=3D, V=2D)
│      │       └─────────────────────── Longitude
│      └─────────────────────────────── Latitude
└────────────────────────────────────── Time (HH:MM:SS UTC)

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Supported ArduPilot Messages

Message	Source	Data Extracted
GPS	GPS fix	Lat, Lng, Alt, Status, HDop, Week, TimeMS
GPS2	Secondary GPS	Same as GPS
BARO	Barometric sensor	Altitude, timestamp
BAR2	Secondary barometer	Altitude, timestamp

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Project Structure

ardu2igc/
├── python/
│   ├── ardu2igc/
│   │   ├── __init__.py          # Package exports
│   │   ├── parser.py            # ArduPilot .bin log parser
│   │   ├── igc.py               # IGC format writer
│   │   └── converter.py         # Conversion engine
│   ├── examples/
│   │   └── convert.py           # CLI tool
│   └── pyproject.toml
├── csharp/
│   ├── Ardu2IGC/
│   │   ├── Ardu2IGC.csproj
│   │   ├── ArdupilotLogParser.cs # Binary log parser
│   │   ├── IgcWriter.cs          # IGC format writer
│   │   └── Converter.cs          # Conversion engine
│   └── Examples/
│       └── Program.cs            # CLI tool
└── LICENSE                       # GPL-2.0

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Building

Python

# Development install
pip install -e ".[dev]"

# With pymavlink support (recommended)
pip install -e ".[pymavlink]"

C#

# Build library
dotnet build Ardu2IGC/Ardu2IGC.csproj

# Build CLI
dotnet build Examples/Examples.csproj

# Release build
dotnet build -c Release

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Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

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License

This project is licensed under the GNU General Public License v2.0 — see the LICENSE file for details.

Copyright (C) Sameer Somnath Sangle

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Acknowledgments

• ArduPilot — The world's most popular open-source autopilot
• FAI Gliding Commission — IGC format specification
• pymavlink — MAVLink protocol and DataFlash log parser
• IGC Format Reference — Developer's guide by Ian Forster-Lewis