The Potential for Unifying Global‐Scale Satellite Measurements of Ground Displacements Using Radio Telescopes

The expansion of globally consistent satellite‐radar imagery presents new opportunities to measure Earth‐surface displacements on intercontinental scales. Yet global applications, including a complete assessment of the land contribution to relative sea‐level rise, first demand new solutions to unify relative satellite‐radar observations in a geocentric reference frame. The international network of Very Long Baseline Interferometry telescopes provides an existing, yet unexploited, link to unify satellite‐radar measurements on a global scale. Proof‐of‐concept experiments reveal the suitability of these instruments as high‐amplitude reflectors for satellite radar and thus provide direct connections to a globally consistent reference frame. Automated tracking of radar satellites is easily integrated into telescope operations alongside ongoing schedules for geodesy and astrometry. Utilizing existing telescopes in this way completely avoids the need for additional geodetic infrastructure or ground surveys and is ready to implement immediately across the telescope network as a first step toward using satellite radar on a global scale. Satellite‐radar imagery is used increasingly to map Earth‐surface displacements, providing unprecedented insights into geohazards and crustal changes. Although the coverage of radar imagery is now global, applications to global‐scale processes are not underway. A fundamental obstacle is the need to transform satellite‐based displacement maps from measuring changes relative to an arbitrary point to being constrained within a globally consistent reference frame. In a new approach, the international network of radio telescopes is shown to be a unique, unexplored, yet readily available, link, requiring no installations of additional infrastructure or ongoing fieldwork. Proof‐of‐concept experiments using telescopes on two continents demonstrate that these instruments simultaneously provide high‐intensity reflections in satellite‐radar imagery, while simultaneously acting as direct ties to a global reference frame. Automated tracking of radar satellites requires only minor additions to existing telescope operations and is therefore immediately ready to implement globally, impacting upon the rapidly growing numbers and diversity of scientists using satellite radar to address geohazards on ever‐increasing scales. This is a first step toward integrating satellite‐radar measurements on a global scale, which will inevitably deliver new understanding of the processes that shape Earth's crust, including a complete, consistent assessment of the contribution of land displacements to relative sea‐level rise. Global‐scale applications of satellite‐radar data require measurements to be connected to an absolute geocentric reference frameThe global network of geodetic radio telescopes provides an unexploited and novel link to unify displacement rate maps globallyTracking of radar satellites is easily implemented into telescope operations without impacting upon existing activities or infrastructure