Building a Ground RTK Base Station

Build a portable RTK base station

UAVCAN parameter configuration

The OneRTK UM982's UAVCAN parameters are automatically configured to ROVER mode by default when it leaves the factory. You need to disable automatic configuration and then use the UPrecise software to configure it to RTK BASE mode.

Wiring: The module is connected to the flight controller using CAN communication, and the flight controller is connected to the computer via a type-c data cable.

Using ardupilot firmware

Connect to the Mission Planner ground station, go to [Initial Settings] → [Optional Hardware] → [dronecan/UavCAN], click [mavlink-can1] to read the CAN device list, find the device named org.ardupilot.zeroone_rtk, click Menu/parameters, find the parameter GPS_auto_config, change the value to 0, and click Write Parameter.

Using PX4 firmware

Connect the flight controller to the Qgc ground station. Scroll to the end of the Parameters section and find and click the parameter [component xxx]. A list of parameters will pop up. Click GPS and find the parameter [GPS_AUTO_CONFIG]. Change the default value from 1 to 0 and click Save. The base station can then proceed to the next step of configuration.

Note: If the parameter [component xxx] is not found, it means that the flight controller does not recognize the RTK module. Check that the parameter UAVCAN_enable is configured to sensors automatic config and that a memory card needs to be inserted into the flight controller.

 

Module serial port configuration

Use Uprecise software to configure the serial port output, connect the RTK to the computer, select the port point to connect, the baud rate will be automatically identified, and the raw data will be displayed.

Configuration Method

1. Send the freset command to reset the module to the default state (default baud rate 115200). As shown in the figure above, the baud rate is 230400 after connection. You can send freset and then select the baud rate 115200 to reconnect.
2. Type the command in the configuration command line and press ENTER on your keyboard.
3. You can only type one line at a time, press enter, and then type another line.

As a base station

Configure the serial port to output RTCM data

Both the USB interface and the UART interface are COM2 interfaces. There is a switch inside the hardware, and only one interface can output data at a time. The configuration commands are as follows:

GPGGA COM2 1

Mode base time 60 2 2.5

rtcm1006 com2 1

rtcm1033 com2 1

rtcm1074 com2 1

rtcm1124 com2 1

rtcm1084 com2 1

rtcm1094 com2 1

saveconfig

 

Missionplanner ground station forwards base station data

Connect to the mission planner, go to Initial Settings > Optional Hardware > RTK/GPS Inject tab, select the baud rate of 115200 (if configured to a different baud rate, select the corresponding one), and click Connect.

 

QGroundcontrol ground station forwards base station data

Connect the oneRTK base station to your computer via the TYPC-C cable. Open QGroundcontrol and the RTK base station will automatically connect to the ground station. Currently, the official QGC does not support connecting to the ONERTK UM982. You need to use the QGC ground station developed by Zero One FlightClick here to download.

When the ONERTK UM982 base station is recognized, a space will appear in the red box below.

RTK GPS must be checked (checked by default), otherwise it will not be able to connect to the ONERTK UM982 base station

 

Use UART interface to output RTCM to mobile station

The base station's RTCM data is sent directly to the mobile station via the RTK's UART interface, rather than being forwarded to the mobile station via the GCS ground station and flight control; the data communication medium generally uses a wireless data transmission link.

The data transmission can be configured in point-to-multipoint mode to broadcast RTCM data to multiple mobile stations. The baud rate of the data transmission must be consistent with the baud rate of the RTK UART interface.