Satellite diversity for personal satellite communications-modeling and measurements

For personal satellite communications systems, the obstacles which produce fading, be they trees, buildings or mountains, are most often of limited angular extent and are present, depending on the environment, for a high fraction of the time. In addition, the motion of the mobile earth station (MES) causes frequent changes of where clear or only lightly shadowed paths to the sky exist, especially as obstacles are usually close to the MES. For this reason, several of the emerging satellite-PCS systems have built satellite diversity into their design, although as yet very little information on the efficacy of satellite diversity mitigation (SDM) exists. This paper presents two contributions to quantifying SDM, one is an analytical model based on image processing of fisheye lens photos taken in urban Japan developed by Akturan (see Ph.D. Thesis, The University of Texas, Austin, TX, USA, 1996), and the other a measurement campaign during which simultaneous transmissions from two GEO satellites (TDRSS) were observed with a single mobile receiver