Android GNSS Logger to RINEX converter

This repository contains a Python script that converts logs from Google's GNSS measurement tools to RINEX

The repository for the GNSS measurement Android app can be found in this link:

https://github.com/google/gps-measurement-tools

Once installed in your Android device, the app will log GNSS measurements and will write a text file with the GNSS measurements. There is a file in the data folder that contains an example data file collected with a Nexus 9 tablet:

data/pseudoranges_log_2017_07_17_13_46_25.txt

This file can be used with this tool to generate a RINEX file that can be then used in GNSS data processing software such as e.g. RTKLib.

Standalone test

If you are developing the code it might be easier to run it as a standalone library.

• in Linux this can be done via

  export PYTHONPATH=$PWD;$PYTHONPATH
  bin/gnsslogger_to_rnx

• in Windows, most of the time PYTHONPATH is not set so its easier to use batch file

  gnsslogger_to_rnx.bat -o nex91980.17o .\data\pseudoranges_log_2017_07_17_13_46_25.txt

That is

gnsslogger_to_rnx.bat -o OUTPUT FILE INPUT FILE

Installation

This package has been built using Pyhton's setuptools. As such, you can install it into your system by issuing the command

python setup.py install

You might need the root password to issue this command. Alternatively, you can install in a non-default directory by specifying the install path with the --prefix option:

python setup.py install --prefix /path/to/instal

Examples

The script has a small help that explains the different options of the program. This help is accessed through the command:

gnsslogger_to_rnx -h

There are several options that allow the user to change several standard RINEX fields ('MARKER NAME', 'RECEIVER TYPE', ...)

Some execution examples follow:

(a) Process the data file and generate a RINEX file in the standard output (discard the error messages)

gnsslogger_to_rnx data/pseudoranges_log_2017_07_17_13_46_25.txt 2> /dev/null

(b) Process the data and save the results into a specified file name (and disregard warning messages)

gnsslogger_to_rnx -o nex91980.17o data/pseudoranges_log_2017_07_17_13_46_25.txt 2> /dev/null

(b) Process the data, trying to "integerize" the observations to the nearest time stamp (i.e. integerize the time stamp to the closest second and modify the pseudorange uaing the PseudoRangeRateMeterPerSecond measurements=. Note: this option does not touch the carrier phase. In theory the same could be done to the phase, but strictly speaking we would need the Doppler. not the PseudoRangeRate measurements.

gnsslogger_to_rnx -i -o nex91980.17o data/pseudoranges_log_2017_07_17_13_46_25.txt 2> /dev/null

This option might be useful to process data from various smartphones at 
once.

(d) Process the data and generate a named RINEX data but maintaining constant the 'FullBiasNanos' instead of using the instantaneous value. This avoids the 256 ns jumps each 3 seconds that create a code-phase divergence due to the clock.

gnsslogger_to_rnx -b -o nex91980.17o data/pseudoranges_log_2017_07_17_13_46_25.txt 2> /dev/null