Quick Answer
A GPS module lets your drone know its position, altitude, and heading. On ArduPilot and PX4 flight controllers, GPS enables loiter mode, autonomous missions, return-to-home, and geofencing. Most GPS modules connect via UART and I2C, and include an integrated compass for heading data.
Why Add GPS to Your Drone?
Without GPS, your drone can only fly in manual or altitude-hold modes. Adding a GPS module unlocks autonomous flight capabilities: the drone can hold its position against wind, follow pre-planned waypoint missions, and return to its launch point automatically if the radio link is lost. For fixed-wing surveying and mapping, GPS is essential for accurate flight paths and geotagged photos.
Types of GPS Module
GPS modules for drones fall into three broad categories, from basic to high precision.
| Type | Accuracy | Typical Use |
|---|---|---|
| Standard GPS (M8N, M10) | 2-3 metres | General flying, RTH, basic missions |
| RTK GPS (M8P, F9P) | 1-2 centimetres | Surveying, mapping, precision agriculture |
| RTK F9P with multiband (L1/L5) | Sub-centimetre | Professional surveying, photogrammetry |
Standard GPS is adequate for recreational pilots who want return-to-home and position hold. If you need centimetre-level accuracy for mapping or surveying, an RTK module is required. RTK systems need a base station and correction link, which adds complexity and cost.
Standard GPS Modules
For most ArduPilot and iNav builds, a basic GPS module with an M8N or M10 receiver is sufficient. These modules cost relatively little, draw minimal power, and provide reliable positioning for waypoint missions and loiter hold. They include an integrated magnetometer (compass) that the flight controller uses for heading. When installing a GPS module, keep it away from ESCs, motors, and power cables to minimise magnetic interference.
RTK GPS Modules
RTK (Real-Time Kinematic) GPS achieves centimetre accuracy by comparing signals from a fixed base station with the rover unit on your drone. The Holybro H-RTK F9P Rover 2nd GPS Module uses the u-blox ZED-F9P receiver with multiband L1/L2 support, making it suitable for professional mapping work. For lighter builds or tighter budgets, the Holybro H-RTK F9P Rover Lite offers the same F9P receiver in a smaller form factor.
Connecting GPS to Your Flight Controller
GPS modules typically connect via two interfaces: a UART serial port for GPS data and an I2C bus for the compass. On Pixhawk boards, the GPS port handles both connections using a single cable. On some boards, the compass connects separately.
- UART (GPS data): Connect TX to RX and RX to TX on the GPS/TELEM port
- I2C (compass): Connect SDA and SCL to the compass bus pins
- Power: 5V from a BEC, not directly from the flight controller
Set the correct GPS protocol and baud rate in your flight controller software. Modern modules default to u-blox at 115200 baud. Our Pixhawk explainer covers port layouts for common boards.
GPS Antenna Placement
Where you mount the GPS module matters more than which module you buy. The antenna needs a clear view of the sky. Mount it on top of your frame, away from carbon fibre, metal, and other sources of RF interference. A quality GPS antenna mounted on a stand-off above the frame will outperform an expensive module buried inside a canopy.
Compass Calibration
Most GPS modules include an onboard compass. After installation, run a compass calibration in Mission Planner or QGroundControl by rotating the drone through all orientations. Compass interference from nearby electronics is a common cause of poor GPS performance. Check the compass mot (interference) reading in your ground station software and move the module if values are high.
GPS and Telemetry
If you want to monitor your drone's position from the ground, GPS data is transmitted back via your telemetry radio link. For long-range builds, a reliable telemetry setup is important. Our drone telemetry radios guide covers the options for sending GPS coordinates and flight data to your ground station. Browse compatible hardware in the drones collection.
RTK vs Standard GPS: Which Do You Need?
If you are building a drone for fun, freestyle, or casual long-range flying, a standard GPS module gives you all the positioning you need. If you are mapping fields, conducting surveys, or doing precision agriculture, invest in an RTK setup from the start. The difference between 3-metre and 2-centimetre accuracy is the difference between a rough overview and a survey-grade map.