Jacob Dahl
0d1fa8d64c
The single gps_inject_data topic served two unrelated purposes: external fixed-base RTCM corrections (from MAVLink GPS_RTCM_DATA or UAVCAN RTCMStream) and moving-base-to-rover RTCM 4072. In a dual-GPS-with-moving-base plus fixed-base setup, the two streams collided on the same queue and the FMU UAVCAN bridge mirrored fixed-base RTCM onto the MovingBaselineData CAN message, breaking rover heading or RTK fix (see PX4/PX4-Autopilot#27088). Split by role: - rtcm_corrections (renamed from gps_inject_data): external RTCM flowing into the vehicle; producers are MAVLink, UAVCAN RTCMStream, and GPS drivers in dump mode. - rtcm_moving_baseline (new): moving-base GPS output intended for a rover; single producer per vehicle. GPS driver routes publishRTCMCorrections() based on a new GPSHelper::isMovingBase() virtual (overridden in UBX). Septentrio's publish_rtcm_corrections() always publishes to rtcm_moving_baseline (only the Secondary moving base calls it). Rover-side consumers (gps, septentrio, uavcan bridge) drain both topics independently; each gets its own stale-link switchover state. FMU UAVCAN bridge: two independent drain loops, one per topic. No more dual-publish of a single uORB message onto both RTCMStream and MovingBaselineData CAN streams. CANnode MovingBaselineDataPub subscribes to rtcm_moving_baseline and drops the bus_type == UAVCAN heuristic that was papering over the conflation. CANnode RTCMStream subscriber switches to PublicationMulti so multiple CAN RTCM sources coexist (e.g. dual rovers outputting MSM7 for logging plus a fixed-base feed). Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com>
The autopilot stack the industry builds on.
About
PX4 is an open-source autopilot stack for drones and unmanned vehicles. It supports multirotors, fixed-wing, VTOL, rovers, and many more experimental platforms from racing quads to industrial survey aircraft. It runs on NuttX, Linux, and macOS. Licensed under BSD 3-Clause.
Why PX4
Modular architecture. PX4 is built around uORB, a DDS-compatible publish/subscribe middleware. Modules are fully parallelized and thread safe. You can build custom configurations and trim what you don't need.
Wide hardware support. PX4 runs on a wide range of autopilot boards and supports an extensive set of sensors, telemetry radios, and actuators through the Pixhawk ecosystem.
Developer friendly. First-class support for MAVLink and DDS / ROS 2 integration. Comprehensive SITL simulation, hardware-in-the-loop testing, and log analysis tools. An active developer community on Discord and the weekly dev call.
Vendor neutral governance. PX4 is hosted under the Dronecode Foundation, part of the Linux Foundation. Business-friendly BSD-3 license. No single vendor controls the roadmap.
Supported Vehicles
 Multicopter |
 Fixed Wing |
 VTOL |
 Rover |
…and many more: helicopters, autogyros, airships, submarines, boats, and other experimental platforms. These frames have basic support but are not part of the regular flight-test program. See the full airframe reference.
Try PX4
Run PX4 in simulation with a single command. No build tools, no dependencies beyond Docker:
docker run --rm -it -p 14550:14550/udp px4io/px4-sitl:latest
Open QGroundControl and fly. See PX4 Simulation Quickstart for more options.
Build from Source
git clone https://github.com/PX4/PX4-Autopilot.git --recursive
cd PX4-Autopilot
make px4_sitl
Note
See the Development Guide for toolchain setup and build options.
Documentation & Resources
| Resource | Description |
|---|---|
| User Guide | Build, configure, and fly with PX4 |
| Developer Guide | Modify the flight stack, add peripherals, port to new hardware |
| Airframe Reference | Full list of supported frames |
| Autopilot Hardware | Compatible flight controllers |
| Release Notes | What's new in each release |
| Contribution Guide | How to contribute to PX4 |
Community
- Weekly Dev Call — open to all developers (Dronecode calendar)
- Discord — Join the Dronecode server
- Discussion Forum — PX4 Discuss
- Maintainers — see
MAINTAINERS.md - Contributor Stats — LFX Insights
Contributing
We welcome contributions of all kinds — bug reports, documentation, new features, and code reviews. Please read the Contribution Guide to get started.
Citation
If you use PX4 in academic work, please cite it. BibTeX:
@software{px4_autopilot,
author = {Meier, Lorenz and {The PX4 Contributors}},
title = {{PX4 Autopilot}},
publisher = {Zenodo},
doi = {10.5281/zenodo.595432},
url = {https://px4.io}
}
The DOI above is a Zenodo concept DOI that always resolves to the latest release. For a version-pinned citation, see the Zenodo record or our CITATION.cff.
Governance
The PX4 Autopilot project is hosted by the Dronecode Foundation, a Linux Foundation Collaborative Project. Dronecode holds all PX4 trademarks and serves as the project's legal guardian, ensuring vendor-neutral stewardship — no single company owns the name or controls the roadmap. The source code is licensed under the BSD 3-Clause license, so you are free to use, modify, and distribute it in your own projects.
