Description

This repository provides examples for orbit determination based on laser ranging data, in the form of Jupyter Notebooks.

The open-source orbital dynamics library Orekit (https://www.orekit.org/) is used for all calculations, and in particular the Python wrapper developed by @petrushy: https://gitlab.orekit.org/orekit-labs/python-wrapper

Installation

Notes on Orekit versions

The Orekit example notebooks are based on Orekit 12.0.1 (previously 10.2 IIRC). The Orekit version is frozen in environment.yml to avoid breaking changes due to new Orekit major releases.

Prerequisites

• micromamba or mambaforge

Install conda environment

Install the conda environment. For this, you can either import the environment.yml file into Anaconda Navigator, or use the command line mamba env create -f environment.yml

If the environment already exists, update it using: mamba env update -f environment.yml

Use

• Enter conda environment: conda activate laserod (or start a terminal directly in the environment using Anaconda Navigator)
• Start Jupyter Lab: jupyter lab
• Jupyter Lab should pop up in your browser at the URL http://localhost:8888

Updating data files

Orekit data

Laser ranging station coordinates

The station coordinates files (position&velocity) are updated from time to time. Check out for files named with the format SLRF2020_POS+VEL_xxxxxx.snx on ftp://cddis.nasa.gov/slr/products/resource/

The newest eccentricities file is always renamed ecc_xyz.snx and is available at ftp://cddis.gsfc.nasa.gov/slr/slrocc/ecc_xyz.snx