> For the complete documentation index, see [llms.txt](https://px4.gitbook.io/px4-user-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://px4.gitbook.io/px4-user-guide/drone_parts/peripherals/gps_compass.md). # GPS/Compass PX4 supports global navigation satellite systems (GNSS) (including GPS, GLONASS, Galileo, BeiDou, QZSS and SBAS) using receivers that communicate via the u-blox, MTK Ashtech or Emlid protocols, or via UAVCAN. It also supports [Real Time Kinematic (RTK) ](/px4-user-guide/drone_parts/peripherals/rtk_gps.md)and **Post-Processing Kinematic (PPK)** GPS Receivers, which extend GPS systems to centimetre-level precision. PX4 can be used with the following compass parts (magnetometers): Bosch BMM 150 MEMS (via I2C bus), HMC5883 / HMC5983 (I2C or SPI), IST8310 (I2C) and LIS3MDL (I2C or SPI). Up to 4 internal or external magnetometers can be connected, though only one will actually be used as a heading source. The system automatically chooses the best available compass based on their *priority* (external magnetometers have a higher priority than internal magnetometers). If the primary compass fails in-flight, it will failover to the next one. If it fails before flight, arming will be denied. ![GPS + Compass](/files/HZHFVdFwbn5RPUKweMqt) :::tip When using [Pixhawk-series](/px4-user-guide/drone_parts/flight_controller/pixhawk_series.md) flight controllers, we recommend using a *combined GPS + Compass* mounted as far away from the motor/ESC power supply lines as possible - typically on a pedestal or wing (for fixed-wing). The internal compass *may* be useful on larger vehicles (e.g. VTOL) where it is possible to reduce electromagnetic interference by mounting the Pixhawk a long way from power supply lines. On small vehicles an external compass is almost always required. ::: ## Supported GNSS and/or Compass PX4 should work with any unit that communicates via the u-blox, MTK Ashtech or Emlid protocols, or via UAVCAN. ### GNSS & Compass This list contains GNSS units (most of which also have a compass). These have been tested by the PX4 dev team, or which are popular within the PX4 community. | Device | GPS | Compass | [RTK](/px4-user-guide/drone_parts/peripherals/rtk_gps.md) | [GPS Yaw Output](#configuring-gps-as-yaw-heading-source) | [Dual F9P GPS Heading](/px4-user-guide/drone_parts/peripherals/rtk_gps/u-blox_f9p_heading.md) | PPK | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------: | :-----------------------: | :-------------------------------------------------------: | :------------------------------------------------------: | :-------------------------------------------------------------------------------------------: | :-: | | [ARK GPS](https://arkelectron.com/product/ark-gps/) | M9N | ICM42688p | | | | | | [ARK RTK GPS](https://arkelectron.com/product/ark-rtk-gps/) | F9P | ICM42688p | ✓ | | ✓ | | | [Avionics Anonymous UAVCAN GNSS/Mag](https://www.tindie.com/products/avionicsanonymous/uavcan-gps-magnetometer/) | SAM-M8Q | MMC5983MA | | | | | | [CUAV C-RTK GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_cuav_c-rtk.md) | M8P/M8N | ✓ | ✓ | | | | | [CUAV C-RTK 9Ps GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_cuav_c-rtk-9ps.md) | F9P | RM3100 | ✓ | | ✓ | | | [CUAV C-RTK2 PPK/RTK GNSS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_cuav_c-rtk.md) | F9P | RM3100 | ✓ | | | ✓ | | [CubePilot Here2 GNSS GPS (M8N)](/px4-user-guide/drone_parts/peripherals/gps_compass/gps_hex_here2.md) | M8N | ICM20948 | | | | | | [CubePilot Here+ RTK GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_hex_hereplus.md) | M8P | HMC5983 | ✓ | | | | | [CubePilot Here3 CAN GNSS GPS (M8N)](https://www.cubepilot.org/#/here/here3) | M8P | ICM20948 | ✓ | | | | | [Drotek DP0804](https://store-drotek.com/920-DP0804.html) (and other [Drotek u-blox GPS/Compasses](https://store-drotek.com/index.php?controller=search\&s=ublox+compass)) | M9N | LIS3MDL | | | | | | [Drotek SIRIUS RTK GNSS ROVER (F9P)](https://store-drotek.com/911-sirius-rtk-gnss-rover-f9p.html) | F9P | RM3100 | ✓ | | ✓ | | | [Emlid Reach M+](https://emlid.com/reach/) - PX4 only supports "ordinary" GPS with this module. RTK support is expected in the near future. | ✓ | ✗ | | | | | | [Femtones MINI2 Receiver](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_fem_mini2.md) | FB672, FB6A0 | ✓ | ✓ | | | | | [Freefly RTK GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_freefly.md) | F9P | IST8310 | ✓ | | | | | [Holybro DroneCAN M8N GPS](/px4-user-guide/drone_parts/peripherals/gps_compass/holybro_m8n_gps.md) | M8N | BMM150 | | | | | | [Holybro Micro M8N GPS](https://holybro.com/products/micro-m8n-gps) | M8N | IST8310 | | | | | | [Holybro Nano Ublox M8 5883 GPS](https://holybro.com/products/nano-m8-5883-gps-module) | UBX-M8030 | QMC5883 | | | | | | [Holybro M8N GPS](/px4-user-guide/drone_parts/peripherals/gps_compass/gps_holybro_m8n_m9n.md) | M8N | IST8310 | | | | | | [Holybro M9N GPS](/px4-user-guide/drone_parts/peripherals/gps_compass/gps_holybro_m8n_m9n.md) | M9N | IST8310 | | | | | | [Holybro DroneCAN M9N GPS](https://holybro.com/products/dronecan-m9n-gps) | M9N | BMM150 | | | | | | [Holybro H-RTK F9P Helical or Base](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_holybro_h-rtk-f9p.md) | F9P | IST8310 | ✓ | | ✓ | | | [Holybro DroneCAN H-RTK F9P Helical](https://holybro.com/products/dronecan-h-rtk-f9p-helical) | F9P | BMM150 | ✓ | | ✓ | | | [Holybro H-RTK F9P Rover Lite](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_holybro_h-rtk-f9p.md) | F9P | IST8310 | ✓ | | | | | [Holybro DroneCAN H-RTK F9P Rover](https://holybro.com/products/dronecan-h-rtk-f9p-rover) | F9P | BMM150 | ✓ | | ✓ | | | [Holybro H-RTK M8P GNSS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_holybro_h-rtk-m8p.md) | M8P | IST8310 | ✓ | | | | | [Holybro H-RTK Unicore UM982 GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_holybro_unicore_um982.md) | UM982 | IST8310 | ✓ | ✓ | | | | [Hobbyking u-blox Neo-M8N GPS with Compass](https://hobbyking.com/en_us/ublox-neo-m8n-gps-with-compass.html?gclid=Cj0KCQjwqM3VBRCwARIsAKcekb3ojv1ZhLz1-GuvCsUuGT8ZZuw8meMIV_I6pgUCj6DJRzHBY9OApekaAgI5EALw_wcB\&gclsrc=aw.ds&___store=en_us) | M8N | ✓ | | | | | | [LOCOSYS Hawk A1 GNSS receiver](/px4-user-guide/drone_parts/peripherals/gps_compass/gps_locosys_hawk_a1.md) | MC-1612-V2b | optional | ✗ | | | | | [LOCOSYS Hawk R1](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_locosys_r1.md) | MC-1612-V2b | | ✗ | | | | | [LOCOSYS Hawk R2](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_locosys_r2.md) | MC-1612-V2b | IST8310 | ✗ | | | | | [mRo GPS u-blox Neo-M8N Dual Compass](https://store.mrobotics.io/product-p/m10034-8308.htm) | M8N | LIS3MDL, IST8308 | | | | | | [mRo u-blox ZED-F9 RTK L1/L2 GPS](https://store.mrobotics.io/product-p/m10020d.htm) | F9P | ✗ | ✓ | | ✓ | | | [Septentrio AsteRx-RIB](/px4-user-guide/drone_parts/peripherals/rtk_gps/septentrio_asterx-rib.md) | AsteRx | ✓ | ✓ | ✓ | Septentrio dual antenna heading | ✓ | | [Septentrio mosaic-go](/px4-user-guide/drone_parts/peripherals/rtk_gps/septentrio_mosaic-go.md) | mosaic X5 / mosaic H | ✓ | ✓ | ✓ | Septentrio dual antenna heading | ✓ | | [Sky-Drones SmartAP GPS](/px4-user-guide/drone_parts/peripherals/gps_compass/gps_smartap.md) | M8N | HMC5983, IST8310, LIS3MDL | | | | | | [SparkFun GPS-RTK2 Board - ZED-F9P](https://www.sparkfun.com/products/15136) | F9P | ✗ | ✓ | | ✓ | | | [Trimble MB-Two](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_trimble_mb_two.md) | F9P | ✗ | ✓ | ✓ | | | | [Zubax GNSS 2](https://zubax.com/products/gnss_2) | MAX-M8Q | LIS3MDL | | | | | Notes: * ✓ or a specific part number indicate that a features is supported, while ✗ or empty show that the feature is not supported. "?" indicates "unknown". * Where possible and relevant the part name is used (i.e. ✓ in the GPS column indicates that a GPS module is present but the part is not known). * [Avionics Anonymous UAVCAN Magnetometer](https://www.tindie.com/products/avionicsanonymous/uavcan-magnetometer/) and [Holybro DroneCAN RM3100 Compass/Magnetometer](https://holybro.com/collections/gps-rtk-systems/products/dronecan-rm3100-compass) is a compass (not a GPS). * Some RTK modules can only be used in a particular role (base or rover), while others can be used interchangeably. * The list may omit some discontinued hardware that is still supported. For example [CubePilot Here+ RTK GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_hex_hereplus.md) is discontinued and may be removed from the list in a future release. The original *Here* has already been removed. Check earlier versions if a discontinued module is not mentioned here. ### Compass/Magnetometer (Only) This list contains compasses (magnetometers) without GNSS. | Device | Compass | DroneCan | | ---------------------------------------------------------------------------------------------------------------- | :-----: | :------: | | [Avionics Anonymous UAVCAN Magnetometer](https://www.tindie.com/products/avionicsanonymous/uavcan-magnetometer/) | ? | | | [Holybro DroneCAN RM3100 Compass/Magnetometer](https://holybro.com/products/dronecan-rm3100-compass) | RM3100 | ✓ | Note: * ✓ or a specific part number indicate that a features is supported, while ✗ or empty show that the feature is not supported. "?" indicates "unknown". ## Hardware Setup Instructions for connecting the GPS (and compass, if present) are usually provided by the manufacturer (at least for more common [Autopilot Hardware](/px4-user-guide/drone_parts/flight_controller.md)). [Pixhawk Series](/px4-user-guide/drone_parts/flight_controller/pixhawk_series.md) controllers typically have a clearly labeled port for connecting the GPS, and the compass is connected to either the I2C or SPI port/bus (depending on the device). The [ARK GPS](/px4-user-guide/drone_parts/peripherals/gps_compass/ark_gps.md), [ARK RTK GPS](/px4-user-guide/drone_parts/peripherals/rtk_gps/ark_rtk_gps.md), [Zubax GNSS 2](https://zubax.com/products/gnss_2), [CUAV C-RTK2](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_cuav_c-rtk.md), [CubePilot Here3 CAN GNSS GPS (M8N)](https://www.cubepilot.org/#/here/here3), and [Avionics Anonymous GNSS/Mag](https://www.tindie.com/products/avionicsanonymous/uavcan-gps-magnetometer/) can also be connected via [DroneCAN](/px4-user-guide/drone_parts/peripherals/dronecan.md). :::warning Pay attention to pinout when connecting the GPS module. While these are all software-compatible, there are several different pin orderings. ::: ## GNSS Configuration The "standard" GPS configuration is provided below. Additional device-specific configuration may be provided in PX4 or manufacturer device documentation (e.g. [Trimble MB-Two > Configuration](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_trimble_mb_two.md#configuration)). :::warning The GPS protocol expected by PX4 defaults to u-blox (by default other GPS types like Trimble, Emlid, MTK, will not be detected) The protocol can be configured with [GPS\_x\_PROTOCOL](/px4-user-guide/advanced_config/parameter_reference.md#GPS_1_PROTOCOL). ::: ### Configuring the Primary GPS GPS configuration on Pixhawk is handled transparently for the user - simply connect the GPS module to the port labeled **GPS** and everything should work. :::note The default [Serial Port Configuration](/px4-user-guide/advanced_config/serial_configuration.md#default_port_mapping) works for most devices. If you are using the *Trimble MB-Two* you will need to modify the configuration to explicitly set the rate to 115200 baud. ::: ### Configuring a Secondary GPS (Dual GPS System) To use a secondary GPS, attach it to any free port, and then perform a [Serial Port Configuration](/px4-user-guide/advanced_config/serial_configuration.md) to assign [GPS\_2\_CONFIG](/px4-user-guide/advanced_config/parameter_reference.md#GPS_2_CONFIG) to the selected port. The following steps show how to configure a secondary GPS on the `TELEM 2` port in *QGroundControl*: 1. [Find and set](/px4-user-guide/advanced_config/parameters.md) the parameter [GPS\_2\_CONFIG](/px4-user-guide/advanced_config/parameter_reference.md#GPS_2_CONFIG) to **TELEM 2**. * Open *QGroundControl* and navigate to the **Vehicle Setup > Parameters** section. * Select the **GPS** tab (1), then open the [GPS\_2\_CONFIG](/px4-user-guide/advanced_config/parameter_reference.md#GPS_2_CONFIG) parameter (2) and select *TELEM 2* from the dropdown list (3). ![QGC Serial Example](/files/qg034e9SZkoVCWPU4iYb) 2. Reboot the vehicle in order to make the other parameters visible. 3. Select the **Serial** tab, and open the [SER\_TEL2\_BAUD](/px4-user-guide/advanced_config/parameter_reference.md#SER_TEL2_BAUD) parameter (`TELEM 2` port baud rate): set it to *Auto*. ![QGC Serial Baudrate Example](/files/mGpYltyyh5SaBo78WFoH) After setting up the second GPS port: 1. Configure the ECL/EKF2 estimator to blend data from both GPS systems. For detailed instructions see: [Using the ECL EKF > Dual Receivers](/px4-user-guide/advanced_config/tuning_the_ecl_ekf.md#dual-receivers). ### Configuring GPS as Yaw/Heading Source GPS can be used as a source for yaw fusion when using modules where *yaw output is supported by the device* (e.g. [Trimble MB-Two](/px4-user-guide/drone_parts/peripherals/rtk_gps/rtk_gps_trimble_mb_two.md)) or when using some [RTK GPS Setups with Dual u-blox F9P](/px4-user-guide/drone_parts/peripherals/rtk_gps/u-blox_f9p_heading.md). When using GPS for yaw fusion you will need to configure the following parameters: | Parameter | Setting | | ----------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [GPS\_YAW\_OFFSET](/px4-user-guide/advanced_config/parameter_reference.md#GPS_YAW_OFFSET) | The angle made by the *baseline* (the line between the two GPS antennas) relative to the vehicle x-axis (front/back axis, as shown [here](/px4-user-guide/config/flight_controller_orientation.md#calculating-orientation)). | | [EKF2\_GPS\_CTRL](/px4-user-guide/advanced_config/parameter_reference.md#EKF2_GPS_CTRL) | Set bit position 3 "Dual antenna heading" to `1` (i.e. add 8 to the parameter value). | :::tip If using this feature, all other configuration should be setup up as normal (e.g. [RTK Positioning](/px4-user-guide/drone_parts/peripherals/rtk_gps.md#positioning-setup-configuration)). ::: ## Compass Configuration Compass calibration is covered in: [Compass Configuration](/px4-user-guide/config/compass.md). The process is straightforward and will autodetect, [set default rotations](/px4-user-guide/advanced_config/parameter_reference.md#SENS_MAG_AUTOROT), calibrate, and prioritise, all connected magnetometers. ## Developer Information * GPS/RTK-GPS * [RTK-GPS](/px4-user-guide/development/hardware/rtk_gps.md) * [GPS driver](/px4-user-guide/development/modules_main/modules_driver.md#gps) * [DroneCAN Example](/px4-user-guide/drone_parts/peripherals/dronecan.md) * Compass * [Driver source code](https://github.com/PX4/PX4-Autopilot/tree/main/src/drivers/magnetometer) (Compasses)