# PX4 Integration Guide

> Connect any UAVLAS precision landing system to PX4: MAVLink port parameters, LANDING_TARGET check in QGroundControl and precision landing missions.

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Site [llms.txt](/llms.txt)

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> **ULSDC-PBIG161026-PX4** · version 1.0.0 · issued October 16, 2026  
> The numbered PDF is the controlled copy: [download it from the portal](https://downloads.uavlas.com).

## Introduction

### Purpose
This guide describes how to connect a UAVLAS precision landing system to a PX4 autopilot, configure the MAVLink port, verify the LANDING_TARGET message and fly a precision landing mission.

### Intended Audience
Integrators and operators setting up precision landing on PX4 vehicles.

### Applicability

This guide applies to every UAVLAS precision landing system that connects to the autopilot over MAVLink: ULS-XCopter, ULS-ProCopter, ULS-Heli and ULS-XSpot. Product-specific installation, pinouts and wiring are in each product's Operation Manual and Interface Control Document.

## Integration

### Preparing for Integration

- Download the latest version of ULS-Tools. Connect all UAVLAS devices to a PC and update their firmware before proceeding.
- Update the autopilot to the latest PX4 version. The stock PX4 firmware supports UAVLAS systems; no custom build is needed.
- Install the transmitter and receiver(s) and wire the receiver to a free autopilot UART (TELEM) port. Pinouts and wiring diagrams are in the Interface Control Document and Operation Manual of your product.
- Configure the transmitter in ULS-Tools.
- Configure the receiver in ULS-Tools (on dual-receiver systems, configure both receivers).

<div class="note">
Generation 3 receivers (ULS-Heli-G3, ULS-XSpot-G3) have an RS422 interface. A UART-only autopilot needs the ULS-XX-UART-RS422 onboard adapter.
</div>

The system communicates with PX4 over MAVLink 2 and reports the target in MAV_FRAME_LOCAL_NED.

**Example of receiver configuration:**

![Receiver configuration for PX4](/library-assets/images/uls-xcopter-g2/px4-receiver-config.png)

*Figure: Receiver Configuration for PX4*

### Configure PX4 Autopilot

Values are provided as an example (Pixhawk4-mini AP):

| PX4 Parameter | Value | Comment |
|---------------|-------|---------|
| MAV_1_CONFIG | TELEM/SERIAL4 | Requires reboot to apply the next parameters |
| MAV_1_FORWARD | Enabled | Forward MAVLink messages |
| MAV_1_MODE | Onboard | Set link mode to onboard |
| SER_TEL4_BAUD | 460800_8N1 | Must match the UART baud rate set in the receiver configuration |

*Table: PX4 Autopilot Configuration Parameters*
### Running and Testing

After configuration and wiring, power up the drone and transmitter. In QGroundControl, go to **Analyze Tools → MAVLink Inspector** and check for the **LANDING_TARGET** MAVLink message.

If the vehicle is providing a LOCAL_POSITION_NED message to the UAVLAS system and is hovering over the beacon, the field `position_valid = 1` will appear in LANDING_TARGET.

To perform precision landing, create a flight plan and enable the Precision Landing option on the landing waypoint.

<div class="important">
LANDING_TARGET may be unavailable when connected over USB. Use a telemetry channel (UART modem, etc.) to connect the drone to QGroundControl during testing.
</div>

![LANDING_TARGET in QGroundControl](/library-assets/images/uls-xcopter-g2/px4-landing-target.png)

*Figure: LANDING_TARGET Message in QGroundControl*

For additional information, see the PX4 documentation at https://docs.px4.io/main/en/


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