Individual T/R module characterisation of the TerraSAR-X active phased array antenna by calibration pulse sequences with orthogonal codes

TerraSAR-X is a high resolution synthetic aperture radar (SAR) satellite due for launch in 2007. Its active phased array X-Band antenna hosts 384 transmit/receive modules controlling the beam steering in azimuth and elevation direction. Precise modelling of the antenna is only possible if the actual characteristics of each individual transmit/receive module are known. TerraSAR-X has been equipped with an innovative characterisation mode based on the so-called PN Gating method. Individual and simultaneous characterisation of all transmit/receive modules is realised under most realistic conditions with the same power loads like in the nominal mode. This paper shows the results of PN Gating measurements on a satellite SAR system.