Multilevel tabulated interaction method applied to UHF propagation over irregular terrain

A multilevel tabulated interaction method (TIM) is described for application to the analysis of exceptionally large two-dimensional (2-D) UHF terrain propagation problems. While standard TIM schemes offer extremely rapid solutions to terrain propagation problems on a medium to large scale (/spl sim/20 km), the computation times increase quadratically with problem size. For problems of extremely large size (/spl sim/100 km), we show how the adoption of the multilevel scheme proves beneficial, reducing computation times and restoring the TIMs computational advantage. Numerical results are provided illustrating the concepts introduced.