Log files are stored on the SD card as binary files and they're encoded for security reasons. However, you can extract the data and view it in a understandable text format (CSV format which can be later exported in XLS, Matlab, or anything else for post-processing and analysis).
You'll need to use the following Python script: ulog2csv.py
If you don't have Python, you can download it here https://www.python.org/downloads/, version 2.7.
To export the log, follow these simple steps:
Open command line
Go to the folder where " ulog2csv.py " script is located
Execute the command:
python ulog2csv.py filename.ulg
(filename.ulg is the path to the log file)
You'll see the folder will all log messages split in separate files
For instance, if you're interested in GNSS (GPS/GLONASS) data you would need GNSS_REPORT.csv file.