HORIZONTAL PARABOLIC EQUATION SOLUTION OF RADIOWAVE PROPAGATION PROBLEMS ON LARGE DOMAINS

The modeling of radiowave propagation in the troposphere often involves field-strength calculations in very large domains, for which the usual parabolic equation techniques become prohibitively expensive. The horizontal parabolic equation method (HPE) provides a rigorous and efficient full-wave solution for this type of problem, taking advantage of the fact that refractive index perturbations in the troposphere are usually confined to a limited portion of the integration domain. Above the height where the medium becomes standard, Fourier and Laplace transform techniques are used to compute the field on a given horizontal, with convolution kernels based on exponential or Airy functions. The field on the initial horizontal may be obtained by any available method. The environment below the initial height may be range-dependent and include terrain variations. Substantial computing gains in both memory requirements and execution time are obtained. The method has been validated by comparison to the standard vertical PE.