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Advanced Application (Unicore Uprecise)
WARNING: Changing GPS configuration can render it inoperable for normal Moving Baseline GPS operation and require resetting the base configuration.
Attach the UM092 to the PC’s USB port. It will appear as a new COM port in Uprecision’s dropbox as shown below, press CONNECT:
At this point the data from the GPS will be shown in the DATA STREAM box. This can be paused to look at past data, or new configuration commands can be entered in the command line box, and sent to the GPS with an “enter” from the PC keyboard.
This will be used to configure the GPS for the following Advanced Applications and can be used to reset the GPS to its factory settings from Holybro for normal GPS use.
The UM982 actually is delivered with this mode enabled. However, if it is attached to an autopilot, it will be re-configured for vehicle use in providing normal GPS data and MovingBaseline yaw data.
Attach the UM982GPS via USB to PC running Mission Planner or QGC.
- GPGGA COM3 1
- mode base time 60 2 2.5
- rtcm1006 com3 1
- rtcm1033 com3 1
- rtcm1074 com3 1
- rtcm1124 com3 1
- rtcm1084 com3 1
- rtcm1094 com3 1
This will start a “survey-in” to determine the GPS precision location. If no re-configuration is done, every power cycle the UM982 will restart the survey. Once the survey is completed, the UM982 will begin outputting RTCM correction data on the USB port.
In the mode command above:
- 60 is the time in seconds that all fixes obtained by the UM982 must remain within an area of horizontal and vertical precision in order for the survey to be declared complete.
- 2 is the horizontal precision in meters all fixes must be within to declare the survey complete.
- 2.5 is the vertical precision required of all fixes for completing the survey.
Smaller values of precision will require longer overall times for the survey to complete. If this is attempted on the bench, it may never complete or require excessively large values for the precision variables (ie not very precise). The values shown will usually result in decimeter or better precision. Any time the UM982 is power cycled or moved significantly (20 or more meters), this command should be reapplied (followed by the saveconfig command) to the UM982 to start a new survey-in for that location.
Now close Uprecise or DISCONNECT it, and start Mission Planner. Under Mission Planner’s SETUP tab, use the RTK/GPS input to connect to the UM982 as shown below using the COM port the UM982 USB port is attached and setting baud rate to 115200 and then pressing connect. Be sure that the Ublox M8/F9P autoconfig checkbox is NOT checked before connecting.
Once connected to Mission Planner, the constellation checkboxes will turn green indicating that satellites in those GNSS systems have been locked in and a bar graph of each constellation satellite strengths will be shown as well as the “surveyed-in” location on a map.
Once RTK data is being processed by the vehicle’s GPS, its status will change to “RTK float” and then to “RTK fixed” in the GCS HUD indicating that its ready for use. “RTK float” means that it is using correction data, but has not moved to the highest precision mode yet.
This connector is attached the the UM982’s auxiliary COM2 port for user specific advances applications such as attaching a telemetry radio to wirelessly communicator RTCM data for RTK correction, instead of having it passed from a ground station like Mission Planner to the autopilot, and the autopilot forwarding it on to the UM982, as is the normal application.
The pinout of the connector is show below: