Effects of Spatial and Temporal Variability of Atmospheric Refractivity on theAccuracy of Propagation Assessments

摘要

Meteorological measurements indicating range dependent refractive structures havebeen documented by several observers (Goldhirsh and Dockery, 1991; Anderson, 1991; Levy and Craig, 1991). A central concern arising from these observations is the effect the assumption of horizontal homogeneity has on the accuracy of propagation assessments, where accuracy is defined as the difference between estimated and measured propagation loss. Complicating the discussion of variability are conflicting goals for propagation model performance versus propagation assessment system performance. With the former, the goal is to minimize error at the time of environmental observation used for the model inputs. With the latter, the goal is to minimize error over the time of use of propagation estimates, a period of time that is often measured in hours with the current level of environmental sensing technology. With these considerations in mind, the effect of spatial and temporal variability of the atmospheric refractive structure on real-time or nearly real-time radio frequency (RF) propagation assessment system performance is examined. (AN).