ENVISAT RA2 : S-BAND PERFORMANCE

The measurement of the range (or actually delay time) performed by an altimeter is affected by the delay of the ionosphere. This delay is in turn dependent on the frequency used. One of the major innovations of RA-2 is the second channel, at S-band (3.2 GHz), that provides the altimeter with the ionospheric correction This paper describes the characteristics of the S-band channel in RA-2, the use of the S-band range in order to correct for the ionospheric delay and its performance. An undesired behaviour of the S-band waveforms was encountered after launch. This behaviour, and the solutions implemented to overcome the problem, are also described.