PX4-Autopilot/docs/en/gps_compass/rtk_gps_gem1305.md

# DATAGNSS GEM1305 RTK Receiver with antenna

GEM1305 is an [RTK GNSS](../gps_compass/rtk_gps.md) receiver with antenna designed and manufactured by [DATAGNSS](https://www.datagnss.com/).

GEM1305 is based on the new generation CYNOSURE IV dual-core GNSS SoC.
It supports RTK functionality with a maximum data update rate of 10Hz, and comes with cables for connecting to GPS ports on most Pixhawk devices.

![DATAGNSS GEM1305 RTK Receiver](../../assets/hardware/gps/datagnss_gem1305/datagnss-gem1305-02.png)

::: info
GEM1305 supports both base and rover options.
It does not yet support _moving base_ mode.
:::

## Where to Buy

- [GEM1305 RTK receiver with antenna](https://www.datagnss.com/collections/gnss-for-drone/products/gem1305) (www.datagnss.com)

  ![DATAGNSS GEM1305 RTK Receiver](../../assets/hardware/gps/datagnss_gem1305/gem1305_hero.png)

- [DGM10 RTK Receiver](https://www.datagnss.com/collections/gnss-for-drone/products/dgm10-rtk-receiver) (same receiver in a casing).

  ![dgm10_rtk_receiver.png](../../assets/hardware/gps/datagnss_gem1305/dgm10_rtk_receiver.png)

## Key Features

- Full constellation, multi-frequency GNSS satellite receiver
- Support RTK with up to 10hz output rate
- IST8310 compass
- Standard UART serial interface
- Lightweight only 50g or 26g(NANO RTK receiver)
- High performance antenna

## Frequencies

- GPS/QZSS: L1 C/A, L5C
- GLONASS: L1OF
- BEIDOU: B1I, B2a
- GALILEO: E1, E5a
- IRNSS: L5

## GNSS

- 128 hardware channels
- 3D accuracy: **1.5m** CEP
- RTK accuracy: **2cm** +1PPM(H), 3cm+1PPM(V)

## Interface

- UART: 230400bps default
- SMA connector for antenna
- Output rate 5Hz default, up to 10Hz
- Main power supply: 4.7~5.2V

## Protocol

- NMEA-0183 output
- RTCMv3 input/output

## Environment

- Operating temp. -20~85°C

## Dimension and Weight

- 55x55x12mm
- 50g (GEM1305) 26g (NANO with Helix)

## Pinout

The board is connected to the autopilot via UART interface.

![GEM1305 connector](../../assets/hardware/gps/datagnss_gem1305/gem1305_connector.png)

The 1.25mm pitch 6P connector (from left: PIN1 to PIN6) supports UART for GNSS and I2C for compass.

## Hardware Setup

RTK requires a base RTK module attached to the ground station, and a rover RTK module on the vehicle.
The data from the base needs to be transmitted to the drone via telemetry radio and inputted into the RTK receiver on the rover.

![RTK setup overview](../../assets/hardware/gps/datagnss_gem1305/setup_overview.png)

The setup/connections for base and rover modules are shown below.

### Base Setup (GCS)

The base station connections are shown in the diagram below, along with the connection to a telemetry radio.

![Base module setup](../../assets/hardware/gps/datagnss_gem1305/base_gnss_setup.png)

Note that for the base we recommend the [NANO RTK Receiver](https://www.datagnss.com/collections/gnss-for-drone/products/multi-band-rtk-receiver-package) because it is easier to setup.

<img src="../../assets/hardware/gps/datagnss_gem1305/nano_rtk_with_case.png" width="500px" alt="DATAGNSS NANO RTK Receiver">

See to [How to setup Base station](https://docs.datagnss.com/#Base_station_setup) for information on how to configure the module for use as a base station (not including step 6 and later, for which you would QGroundControl instead of Mission Planner).

### Rover Setup (PX4)

The rover setup showing connections to a GPS port and the (required) connection to a telemetry radio are shown in the diagram below.

![Rover module and pixhawk big picture connections](../../assets/hardware/gps/datagnss_gem1305/rover_gnss_setup.png)

The diagram below shows the wiring from the `GPS2` port on the Pixhawk 6c flight controller.
Note that an appropriate cable is supplied for this purpose.

![Rover module setup](../../assets/hardware/gps/datagnss_gem1305/pixhawk_connections.png)

GPS and RTK configuration on PX4 via _QGroundControl_ is plug and play (see [RTK GPS](../gps_compass/rtk_gps.md) for more information).

## Package List

- GEM1305 RTK Receiver
- DG-6P-C01, GH-1.25mm-6P cable

## Resources

- [GEM1305 Wiki](https://docs.datagnss.com/gnss/rtk_receiver/GEM1305/) (DATAGNSS WiKi)
- [HED-10L Heading RTK Receiver](https://docs.datagnss.com/gnss/rtk_receiver/HED-10L/)
- [NANO HRTK Receiver](https://docs.datagnss.com/gnss/rtk_receiver/NANO/nano-helix-rtk/)

## More information

- [NANO RTK Receiver](https://www.datagnss.com/products/nano-rtk-receiver)
- [HELIX Antenna for RTK](https://www.datagnss.com/collections/rtk-antenna/products/smart-helix-antenna)
- [RTK Antenna AGR6302G](https://www.datagnss.com/collections/rtk-antenna/products/antenna-agr6302g)
- [AT400 RTK Antenna](https://www.datagnss.com/collections/rtk-antenna/products/at400-multi-band-antenna-for-rtk)