FocusPOD - A POD and Geodesy SW Package

Since 2021, GMV has been developing FocusPOD, a new Precise Orbit Determination (POD) and Geodesy software package designed to serve as a unified framework for multi-technique space geodesy. Written in modern C++17 and Python3, FocusPOD is built around four core design principles:

1. Object-Oriented Architecture, ensuring modularity, scalability, and efficient handling of large geodetic datasets;
2. Data–Algorithm Separation, enabling consistent use of the same algorithms across multiple observation types;
3. Centralized Data Model, which structures heterogeneous measurements (GNSS, DORIS, SLR, VLBI) in a coherent, relational format;
4. Multi-Use Case Support, allowing expert interactive use as well as automated operations and machine-to-machine interfaces.

FocusPOD supports precise orbit determination based on GNSS, DORIS, and SLR measurements for Copernicus Sentinel-3 and Sentinel-6 missions, achieving millimeter- to centimeter-level orbit precision. These capabilities enable cross-validation and bias estimation between techniques, supporting the refinement of reference frames and the study of co-locations in space. In addition, VLBI processing has recently been incorporated, allowing geodetic and astrometric applications such as the joint estimation of Earth Orientation Parameters (EOPs), station coordinates, and celestial source positions, in support of the Galileo Reference Centre (GRC) v2 project from the EUSPA. The software also provides a flexible environment for comprehensive observation simulation, including realistic noise effects and modelling uncertainties, enabling controlled performance assessment and sensitivity analyses across techniques.

This contribution presents FocusPOD’s multi-technique POD capabilities, demonstrating how the combined use of DORIS, SLR, and GNSS enhances orbit consistency and supports integrated space-based co-location experiments. The results, based on Sentinel-3A and -3B and Sentinel-6 orbit determination and combination, highlight the potential of a unified geodetic processing environment for the Genesis mission and future global reference frame realizations. Ongoing developments include normal equation stacking for TRF-like global solutions and the integration of GNSS network processing within the same software framework.