Spaceborne GNSS Radio Occultation Instrumentation for Operational Applications

摘要

Radio occultation (RO) instruments using GNSS signalsrnare specialised spaceborne receivers designed to providernhighly accurate measurements from which one can derivernvertical profiles of the temperature, pressure and humidityrnin the atmosphere, as well as profiles of electron contentrnin the ionosphere. A family of operational RO instrumentsrnis being developed for a number of European spacernprojects since 1996. The basic functions of the instrumentrninclude: reception of signals that have crossed thernatmosphere at varying altitudes by means of two antennarnarrays; acquisition of such signals, also during the risern(ascending) RO events, when a signal first appears afterrncrossing dense tropospheric layers causing large dynamicsrnin amplitude and phase; robust signal tracking to providernprecise amplitude and phase measurements; on-boardrnprocessing to support RO event predictions, also to aid therntracking. We summarise the main requirements andrnillustrate the main technical features adopted. Thernexpected performance is also presented.