Here I would like to show the processes of getting the trigger positions from SD-card log files of base and rover.
Roughly speaking, the log file in Alpha’s SD card contains
- [both base and rover sides] GNSS raw measurement data.
- [rover side] GNSS raw measurement data at regular sampling points at 1/5/10 Hz.
- [rover side] GNSS raw measurement data at trigger points (trigger input comes from pin 3 of the 4-pin connector on Alpha).
The processes to retrieve trigger positions will be
- From base Alpha, we get logged base RTK correction raw data file, say, “b.DAT”
- From rover Alpha, we get logged rover positioning raw data file, say, “r.DAT” (with time stamps of regular sampling points and user trigger points)
- Feed files “b.DAT” and “r.DAT” into RTKLib utility tools do PPK processing, and we can get the recorded path file “*.pos” with timestamps and positions.
- Use the RTKViewer’s new feature “SD Timestamp Acquisition” (will be provided later in version update) to extract timestamps of trigger points from “r.DAT” file (mentioned in point 2). The triggered timing will be stored in the output file named “r.DAT.txt”
- Use PC utility locator.exe to find positions of trigger points by providing path file “*.pos” (mentioned in point 3) and triggered timing file “r.DAT.txt”, you can specify the output filename like “out.txt”
PPK results and trigger points at turning points and middle way are shown here.
PC utility locator.exe and sample files are zipped in the rar file.