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ppp-tools

FOSSA Status

This is a collection of python scripts for GPS-Precise Point Positioning post-processing of RINEX files. GPS-PPP solutions can be found with the following open source software packages:

In addition to the GPS-PPP software some utilities may be required:

  • GFZRNX (https://gnss.gfz-potsdam.de/services/gfzrnx) for RINEX file splice, split, repair, format conversion (RINEX 2 to 3). As of 2021 June the version is gfzrnx-1.15-8044
  • Teqc, for concatenating many 1-day RINEX files into multi-day files, https://www.unavco.org/software/data-processing/teqc/teqc.html, install it to e.g. /usr/local/bin, and verify with $ teqc -version that it is working. as of 2018 March the latest version is "2018Jan11". Teqc is no longer maintained, but binaries are available.
  • RNXCMP, for decompressing Hatanaka compressed RINEX files, http://terras.gsi.go.jp/ja/crx2rnx.html, install to e.g. /usr/local/bin and verify that CRX2RNX is working with $ CRX2RNX -h As of 2018 March the latest version is 4.0.7.

Running PPP

The steps for PPP-processing are roughly:

  1. Download RINEX files (from e.g. BIPM or other ftp-server)
  2. Optionally pre-process RINEX files (i.e. decompress Hatanaka-files, and/or assemble daily files into longer batch)
  3. Download SP3 orbit and CLK clock files (from e.g. CODE or other IGS datacenter)
  4. Run PPP-algorthm
  5. Post-process and visualize the results

Post-Processing PPP results

Post-processing may include:

  • Calculation of double-differences for time-transfer purposes, e.g. (StationA - IGS) - (StationB - IGS) = StationA - StationB.
  • Some UTC-laboratories submit both a RINEX file and an "LZ" file with the offset between the RINEX receiver clock and the UTC-realization. The PPP receiver-clock result should be modified using the LZ file.
  • Plotting using matplotlib
  • Calculation of Allan deviations or other statistics (using e.g. allantools)
  • Comparison to UTC-UTC(k) numbers published by BIPM monthly in Circular-T, or to Rapid-UTC published weekly.

Folders

The scripts store input and output files under the main folder:

  • 'stations' stores RINEX and LZ files from receiver stations
  • 'products' stores clock, ephemeris/orbit, and ERP files from IGS datacenters
  • 'common' has common files
  • 'results' stores the output results of PPP processing
  • 'UTC' has Circular-T data from the BIPM ftp site.
  • 'UTCr' has rapid-UTC data from the BIPM ftp site.
  • 'doc' has documentation
  • 'temp' is used as a temporary directory for gpspace calculations

ESA gLAB installation

  • dowload package from http://gage.upc.edu/gLAB
  • build binary gLAB_linux" with "make"
  • test that it works $ ./gLAB_linux -help
  • move the binary to e.g. /usr/local/bin

RTKLib installation

License

FOSSA Status