Research Report: A Black Hole in Earth science

Figure 1: Scientific observations with GNSS radio occultation (GNSS-RO), GNSS grazing-angle reflectometry (GNSS-GR) and GNSS reflectometry (GNSS-R) techniques from low-Earth orbit (LEO). (Figure provided by the author) Global navigation satellite systems (GNSS) for peaceful uses are facing a hard reality…