maoya0428 / rtcm-ssr-python-demonstrator

RTCM-SSR Python Demonstrator

v1.1

1. Introduction

   the RTCM-SSR Python Demonstrator is a software package designed to decode RTCM-SSR binary files providing the RTCM-SSR message content in a human-readable format and to translate them into Observation Space Representation (OSR), dealing with general GNSS-related aspects.

   The RTCM-SSR Python Demonstrator can perform the following main tasks:

   • decoding RTCM-SSR messages v3 and RTCM-SSR proposed messages
   • computing influence from SSR components on a specific user location.

   The GNSSs implemented are GPS, GLONASS, Galileo, Beidou, QZSS. The decoding involves the following messages:

   • ephemeris
   • satellite orbit and clock corrections
   • code bias
   • phase bias
   • ura
   • high rate clock
   • global ionosphere.

   The computed OSR components are sorted by received epoch time and satellite ID. Furthermore, the week of the ephemeris used for the computation is reported. The output quantities are the following:

   • elevation
   • clock correction
   • orbit correction
   • global ionosphere correction
   • Shapiro effect
   • wind up
   • phase bias
   • code bias.

2. Requirements

   the RTCM-SSR Python Demonstrator 1.0 has been developed and tested in Python 3+ environment on Windows.

   The following elements are needed in order to use the demo:

   • a computer with Windows operating system
   • a Python 3+ installation (e.g. downloading Anaconda from https://www.anaconda.com/)
   • bitstruct Python module (e.g. from cmd: "conda install bitstruct -c conda-forge")
   • crcmod Python module (e.g. from cmd: "conda install crcmod -c conda-forge")
   • tkinter Python module (e.g. from cmd: "conda install tk -c conda-forge")
   • an rtcm binary file (e.g. *.rtc).

3. Notes

   The results of the decoding of the input rtcm file (binary) is saved in a text file named as the input file with ".ssr" extension.

   The computed influence from SSR components on user position is saved in a text file named as the input file with ".osr" extension. Be aware that the week reported in this file is the week of the used ephemeris. Therefore, during the crossing between one week to another, the epoch could refer to a different week (i.e. ephemeris week + 1). Furthermore, be aware that the output is sorted per epoch of the received message.

   Moreover, an additional txt file is printed out with ionosphere related parameters, e.g. pierce point parameters. It is saved in a text file named as the input file with ".ion" extension.

   The script "start_rtcmssr_demo.py" provides a simple GUI to execute the demo. The required inputs are:

   • path of the rtcm-ssr binary file
   • name of the rtcm-ssr file
   • output folder (optional)
   • ellipsoidal (WGS84) latitude, longitude, and height (if no input coordinates are given default values are considered: lat = 52.5 deg, lon = 9.5 deg, height = 100 m)
   • year and day of the year (DOY).

   The RTCM-SSR proposed messaged are updated to version v08u. If, for Galileo, QZSS, SBAS and BDS the version v07 is needed, please refer to the rtcm_decoder.py version before 2020-03-16.

4. Additional information

   Geo++ GmbH is the owner of the RTCM-SSR Python Demonstrator, developed receiving funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No 722023.