kristinemlarson / gpssnrpy

This repository extracts SNR data from GPS RINEX files and computes elevation and azimuth angles from the GPS navigation file. There are also various utilities (for downloading files).

gpssnrpy

Table of Contents

1. Installation
2. gpssnr usage
3. RINEX downloader
4. Orbit downloader
5. Future work and acknowledgements

The gpssnr python library (gpssnrpy) will allow python users easy access to RINEX translators currently only provided in Fortran - gpsSNR and gnssSNR. This first version is a port of gpsSNR. I have also included some utilities that I originally packaged with gnssrefl.

Installation

• git clone https://github.com/kristinemlarson/gpssnrpy

• cd into gpssnrpy, set up a virtual environment and activate it.

• pip install .

Usage of gpssnr

Inputs:

• RINEX v2.11 observation filename
• output filename
• RINEX v2.11 navigation filename
• SNR choice (99, 66, 88, 50) as defined at the gnssrefl website

Optional

• -dec decimation (seconds)

Sample usage:

• gpssnr rinexname outputname navname 99

I have provided a small obs file (and nav file) you can use to test the code:

• gpssnr p1011500.20o p1011500.snr auto1500.20n 99

Download RINEX files

• download_rinex station year month day

• download_rinex station year doy 0

The station name, station, must be four character and lower case. The default is RINEX version 2.11 and low-rate files. Please use -h to find out how to download high rate data or version 3.

Optional:

• archive

These are the currently supported archives: sopac, unavco, sonel, cddis, nz, ga, bkg, ngs, nrcan

You need to install CRX2RNX for true access to these RINEX files. It should be stored in a folder with the environment variable EXE

Download orbit files

• download_orbits src year month day

Sample usage:

• download_orbits nav 2020 150 0 (for doy 150)

• download_orbits nav 2020 12 31 (for December 31)

orbit sources (src) currently allowed (lowercase):

• nav : GPS broadcast, perfectly adequate for reflectometry.
• igs : IGS precise, GPS only
• igr : IGS rapid, GPS only
• jax : JAXA, GPS + Glonass, within a few days, very reliable
• gbm : GFZ Potsdam, multi-GNSS, not rapid
• grg: French group, GPS, Galileo and Glonass, not rapid
• wum : Wuhan, multi-GNSS, not rapid

Future work and acknowledgements

I am still working on this documentation. I will be adding instructions on how to use these as libraries.

Multi-GNSS capabilities, a la gnssSNR, will be added.

This capability will be added to gnssrefl.

Kristine M. Larson https://kristinelarson.net

Thank you to the developers of numpy for providing excellent documentation for f2py and raxod502 for his package management help!