This paper examines the applicability of some common statistical models for the land mobile satellite channel to K-band pilot tone data measured from the Advanced Communications Technology Satellite (ACTS) by the ACTS Mobile Terminal (AMT) developed at JPL. It is shown that the advantage of the narrowbeam antenna (suppression of multipath interference) is accompanied by two disadvantages: exaggerated shadowing effects and pointing errors. The ability of the statistical models outlined in NASA Publication 1274 to model the shadowing effects is relatively good for those models which use a time share between shadowed and unshadowed propagation. The ability of these same models to describe the pointing errors is limited. A new model, the generalized total shadowing model, is proposed to account for the pointing errors. A summary of the results show that the generalized total shadowing model accurately represents the fade statistics of the experiment runs and that the parameters of the model reveal insight into the mechanisms affecting the received power on the land mobile satellite channel.
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