The relative performance of numeric and analytic ray tracing

The operation of high frequency (HF) skywave communication and radar systems can be enhanced by the application of accurate and fast ray tracing coupled with realistic and near real-time ionospheric specification models. Norman and Cannon have introduced a new two-dimensional analytic ray tracing method, known as SMART (segmented method for analytic ray tracing). It approximates the horizontal gradients along the ray path by automatically segmenting the ionosphere and has the ability to ray trace through much more complicated ionospheres than conventional tilting methods. In this paper the assessment of SMART is extended to ground range, phase path, group path and divergent power loss. Results from SMART are compared to the results obtained from two tilted ionosphere analytic approaches and also with the results from numerical ray tracing. A very accurate numerical ray tracing package HIRT (homing-in ray tracing) Norman et al. [1994] is used to determine the percentage error in the analytic techniques. Computer run times are also given