C-RTK 9P User guide(for ArduPilot)
This tutorial uses the Mission Planner ground station software and the Arducopter-3.5 firmware. If you are using PX4 firmware and QGroundControl ground station software,Please read the PX4 RTK docs.
Please prepare the following hardware devices and perform hardware connection before use.
Base station configuration
This is not necessary if you use C-RTK BASE.
If you use Ardupilot firmware to build an RTK differential system, you need to perform base station-side positioning configuration and data forwarding through the missionplanner. During the positioning configuration of the base station, there is no need to start the mobile station and drone.
- Open the Mission Planner
- Enter the initial settings
- Click on optional hardware
- Click on RTK/GPS Inject you will see the following page:
- Set the base station port in the upper left corner
- Click connect
- In the SurveyIn Acc section, enter the absolute geographic accuracy that you expect your C-RTK base station to achieve. In the Time field, enter the shortest search time you want.
- Click Restart (the ground station will transfer the data you input to the C-RTK 9P base station, and the base station will start a new round of search star positioning)
- You will see the following page: During the search process, the current search star positioning will be displayed in the box on the right side of the Mission Planner page:
- Position is invalid: The base station has not yet reached a valid location;
- In Progress: Search Star is still in progress;
- Duration: The number of seconds the current search star has been executed;
- Observation: the number of observations obtained;
- Current Acc: The absolute geographic accuracy that the current base station can achieve.
- The green bars below the Mission Planner show the satellite and satellite signal strengths that the current base station has searched for. In an ideal environment, the C-RTK 9p can have an absolute accuracy of 2.5m in a matter of seconds. If you need higher absolute accuracy, it may take a long time.
The absolute geographic accuracy of the base station here will affect the absolute geographic accuracy of the mobile station without affecting the relative accuracy of the base station and the mobile station. If your application does not require drones with high absolute geographic accuracy, you don't need to set the base station's accuracy too high, resulting in longer search times. Even if the accuracy of the base station is 1.5~2m, the positional accuracy of the mobile station relative to the base station can still reach the centimeter level.
After the C-RTK 9P base station search star is completed, the Mission Planner will display the following page:
The figure below shows that the indicator of the base station status is displayed in green, while the three satellite systems of GPS, Glonass and Beidou are displayed in green. The box on the right shows the status as Position is valid and displays the current latitude and longitude.
RTK positioning status
Using the paired digital transmission module to connect to the same Mission Planner ground station, the data of the base station will be transmitted to the C-RTK rover station on the drone through the data transmission module. On the main page of Mission Planner, you can see that the current GPS status of the drone is displayed as RTK Float/RTK Fixed/3D RTK, indicating that the UAV's positioning has entered the RTK state.
RTK Float is a floating point solution.
RTK Fixed is a fixed solution.
RTK Fixed has higher accuracy and is extremely environmentally demanding, and positioning can enter the RTK Fixed state when the signal is good enough。