After a Wingtra PPK flight mission in our Data folder there is an SBF file which contains our GNSS data for post process the positions of the geotags. It is important that this data is error free because it is not likely once you leave the field it will be able to be fixed. This article is to explain proper quality control to ensure that the mission will process successfully.
Download RxTools
Septentrio is the PPK receiver we use on the aircraft so in order to analyze the files we need to download a program called RX TOOLS
- The first method is to download online from Septentrio support. You may need to provide an email address. https://www.septentrio.com/en/support/software/rxtools
- The second method is to open the orange dongle provided with Wingtra and navigate to the RxTools folder to download.
SBF Analyzer
There are a couple of ways to run a file through SBF analyzer. Once the program is launched a new pop up will display. After a flight there will be 1 SBF file in the OUTPUT folder of WingtraPilotProjects. After you process in WingtraHub you will notice there are 3 SBF files in the OUTPUT folder that are automatically loaded.
Before WingtraHub: Check in the field this file.
After WingtraHub: If there is a processing issue analyze or send the folder to support with a screenshot of the error message in WingtraHub.
Do not mess with the naming convention or deleting files as it could cause issues.
Open up SBF Analyzer
- Right click on the file and click analyze SB
- Set default program to SBF analyzer so when you click the file it opens automatically
- Open SBF analyzer and specify the file location
Navigating through SBF Analyzer
Once the location of the file is specified, we need to select which plots, graphs, and information to analyze. If you want details regarding each selection click on the help tab and open up the manual to use as a guide.
- For simplicity select only the following plots to be shown: Carrier to Noise, Number of Satellites, Planimetric plot, Height, Signals, and General Information
- Click analyze on the bottom right to begin the process
Analyzing the plots
General Information:
- First, start on the following window with the general tab
- On the message statistics tab check ExtEvent1 to see if the images match the triggers.
- Check the time and date of the flight to see if it makes sense with the base station
- If the duration is under 10 minutes, it could explain less accurate results or failed processing
- Check that there isn’t missing valid time
- Check that the signals are using GPS and GLONASS L1 and L2
Number of satellites:
- Hover over the SVs in track and SVs in PVT. There should be around 20 satellites tracked
Carrier to noise window:
- Check if the carrier to noise fulfills our Inop requirements. L1-C/A, L1-C/A: Best Satellite over 45 dB, 7 Satellites over 40 dB! L2C, L2-C/A: Best Satellite over 36 dB, 7 Satellites over 30 dB!
Planimetric and height plot:
- Review the plot to see if it makes sense with the flight plan and that there is no gaps in the data. The planimetric shows the horizontal position of the flight plan every 10hz and the height shows the drones vertical value.
Signals plot:
- Review the signals plot to check for quality of lock. Look for cycle slips. If there are a lot of gaps the flight may be too short or the quality of signal is bad.
Summary
Main things to check:
- That SBF file is present in data folder and there it contains data -
- There is no missing data or gaps – check general, planimetric, and height
- Triggers match images -
- Time matches base file – check general information and rinex
- Signal quality is good – check carrier and signals
Example of bad data:
