pyRugged, A sensor-to-terrain mapping tool

What is it?

pyRugged is a python geolocation library used for satellite imagery (pyRugged is the python version of Rugged). It allows to map image coordinates (pixel, line) with geographic or projected coordinates (lon, lat or x, y, h) by computing the intersection of the sensor's lines of sight with the Earth's terrain. This mapping is essential for georeferencing raw satellite images. It is a key component when projecting an image on ground.

Sensor-to-terrain mapping library

pyRugged provides the tools to model any type of sensors rigorously/physically, to process all the spacecraft navigation data (position, velocity and attitude), and to take into account Digital Elevation Models (DEM) to represent the surface of the Earth. It is on this last point that Rugged gets its name from; Rugged deals with rugged terrains.

pyRugged relies on Orekit for all what concerns transformations between coordinate systems (inertial/terrestrial) and orbital data but what pyRugged brings on top of Orekit, is the capacity to deal with the DEM. Orekit could have been used for intersecting a line of sight with the Earth's ellipsoid but it is not its mandate to know what the Earth's surface looks like as it is a space dynamics library. It is in this perspective that we decided to provide a separate package for those users who look for a robust tool for geometric processing.

Features

• Direct/inverse location

• Can support several types of Digital Elevation Models, including user-provided models

• Several intersection models algorithms available

• Both modern and legacy models for Earth rotation

  • Lieske (1976), Wahr (1980),
  • Mathews, Herring, Buffett (2002)
  • Capitaine (2006)

• Complete set of corrections applied for greater accuracy

  • δΔψ, δΔε on precession nutation (about 3m correction since 2013, steadily increasing)
  • ΔUT₁, lod on proper rotation (can theoretically reach up to 400m)
  • u, v pole wander (polhody), (about 15m correction)
  • light time correction (about 1.2m)
  • aberration of light correction (about 20m)
  • line-of-sight curvature in geodetic coordinates, (0m at nadir, 10m at 30° dive angle, hundreds of meters for skimming los)
  • atmospheric refraction

• Not limited to Earth

Free (open source) software

pyRugged is freely available, with all related documentation and tests.

Rugged is distributed under the Apache License version 2.0 , a well known business-friendly license. This means anybody can use it to build any application, free or not. There are no strings attached to user code.

Getting orekit jcc build

PyRugged relies on python wrapper for orekit build with JCC.

The project https://gitlab.eopf.copernicus.eu/geolib/orekit-jcc is aiming at providing tool to build orekit jcc packages.

Already build packages are available in https://gitlab.eopf.copernicus.eu/geolib/orekit-jcc/-/packages

Who is behind it?

Rugged has been in development since 2014 inside CS GROUP and is still used and maintained by its dual teams of space dynamics and image processing experts. pyRugged, the python version of Rugged has been started in 2022.

Several major actors of space research and industry are interested into this project.

Rugged forum is available for any question or request about Rugged (see contact section).

We do our best to provide you with a quality code:

Documentation

follow : README to build sphinx doc

Getting help

The main communication channel is our forum. You can report bugs and suggest new features in our issues tracking system. When reporting security issues check the "This issue is confidential" box.

Contributing

Please take a look at our contributing guidelines if you're interested in helping!