How fragile is the global geodesy supply chain? A case study of the ILRS network.

The geodetic community provides essential data, products and services that support critical sectors of our modern economies. Positioning, navigation, timing, infrastructure monitoring, natural hazard modelling and early warning systems, climate change science, are just a few examples of applications that depend on the existence of the so-called Global Geodesy Supply Chain (GGSC). The GGSC comprises the entire cycle of creation of geodetic products and their delivery to the users. It includes structural elements (e.g. ground and space assets, data centres, analysis and combination centres) and operational elements that support these functions (e.g. human resources, governance structures).

Since its establishment in 2023, the United Nations Global Geodetic Centre of Excellence has been working with the international geodetic community, national agencies and Member States to strengthen the GGSC. The strategic objectives of these efforts are outlined in the 1st Joint Development Plan for Global Geodesy. The expert evidence gathered by the UN-GGCE indicates weaknesses in the GGSC, which threatens socio-economic activities that rely on the supply of accurate, precise, stable and timely geodetic products.

In order to ascertain more quantitatively the fragility of the ground networks, we have conducted simulation studies focusing on what appear to be particularly concerning elements. Here we will discuss results for the Satellite Laser Ranging network, showing how the loss of relatively few stations can lead to significant degradation of the ILRS products and therefore to the combined global terrestrial reference frame. The lower quality of the global products obtained in the simulated scenarios would most obviously affect the scientific goals of the Global Geodetic Observing System, and its commitment to continuously monitor changes in the Earth system in an integrated manner. Likewise, operational applications dependent on a high-quality global terrestrial reference frame would also be affected.


* The findings, interpretations, and conclusions expressed herein are those of the author(s) and do not necessarily reflect the views of the United Nations or its officials or Member States.