1. The pressure-sensor does not always calibrate to 0m. Sometimes, it starts at -10m when starting up the drone. Why?
The pressure-sensor is accurate with an error range of about 2m. When we start up the drone, the movements of the propellers will momentarily affect the air pressure around the pressure-sensor, which may have an effect on the pressure-sensor’s calibration. Weather conditions will also influence the pressure sensor’s accuracy. The pressure-sensor also has a drift of 1cm every second.
For the latest firmware version 3.1.0, we will calibrate the pressure-sensor to 0m when the drone is about to taking off.
2. What does openGroundStation() do?
The openGroundStation is designed to open the Ground Station. When the API is called, it sends some data to the drone which tells the drone to turn on the Ground Station mode so that we can take the control of the orientation and do whatever we can using the Ground Station API.
You can check the demo of GsProtocalDemoActivity.java to see how to use it.
3. In DJIGroundStationWaypoint, what does the speed property and the heading property mean?
speed means the drone’s speed between the previous waypoint and the current waypoint. It is the combination of speeds in horizontal and vertical directions, not just a speed in the horizontal direction or a speed in the vertical direction.
heading is the angle between the drone’s nose and the north direction.
4. How can we identify SPS frame and PPS frame in the raw H264 data from camera?
PPS frame starts with 0x00 0x00 0x00 0x00 0x01 0x68, ends with 0x00 0x00 0x00 0x01.
SPS frame starts with 0x00 0x00 0x00 0x00 0x01 0x67, ends with 0x00 0x00 0x00 0x01.
5. What is the difference between SDK autopilot firmware and standard firmware?
The autopilot firmware for SDK supports API flight control mode, in which users can use waypoint mission, and position, velocity and attitude control commands. Moreover, some experimental functions to improve flight control performance are added.
6. How can the GPS information accuracy of photos taken by UAV be improved?
Update the firmware version as follows: camera: 1.3.1; main controller: 3.1.2; central board: 188.8.131.52.
After upgrading, use SDK’s function SET_CAMERA_GPS to record the GPS info in photos taken by UAVs. We find the accuracy of the GPS info (latitude, longitude) can reach 10 digits after the decimal point. Generally the accuracy with 6 digits after the decimal point can reach an error within 1 meter.
When using SET_CAMERA_GPS function, it would record the GPS info that UAV receives. So it is recommended to stay still a moment for SET_CAMERA_GPS to record the GPS info of the interested place.
You can upgrade the camera firmware version by changing the name of firmware_plus_v1.3.1g.bin to firmware_plus.bin, and storing it in SDCard, inserting the SDCard to P2V+.
The firmware version of main controller and central board can be upgraded by using the one key for upgrading function after installing the assistant software.