# ppp-tools

**Repository Path**: ouyang_mingjun/ppp-tools

## Basic Information

- **Project Name**: ppp-tools
- **Description**: Scripts for GPS-Precise Point Positioning based on RINEX files
- **Primary Language**: Unknown
- **License**: GPL-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2021-03-16
- **Last Updated**: 2025-04-27

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# ppp-tools
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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 software packages: 
* rtklib, http://www.rtklib.com/
* ESA gLab, 5.1.3 released 2018-01 http://gage.upc.edu/gLAB
* NRCan gpsppp (CSRS-PPP) (NOTE: this fortran code is not publicly available, but can be obtained from NRCan/CSRS for academic/non-commercial use)

In addition to the GPS-PPP software some utilities may be required:
* 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"
* 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 gps-ppp 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

## NRCan gpsppp Installation

This Fortran code is not publicly available, but can be obtained from NRCan/CSRS for academic/non-commercial use.

The gfortran package is required on Ubuntu. NRCAN gpsppp is compiled with

```
Dist34613b/source/$ gfortran -o gpsppp *.f
```

The resulting binary can be placed in e.g. /usr/local/bin

## RTKLib installation

* clone from https://github.com/tomojitakasu/RTKLIB
* run "make" in RTKLIB/app/rnx2rtkp/gcc
* move the binary "rnx2rtkp" to e.g. /usr/local/bin
* test with "rnx2rtkp -help"


## License
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