The Theory and Use of a Raytracing Model Developed at USAFETAC
AIR FORCE ENVIRONMENTAL TECHNICAL APPLICATIONS CENTER SCOTT AFB IL
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This report describes the theory and use of the USAFETAC ray trace model RAYTRA. In this model atmospheric refraction is calculated using geometric optics and a single atmospheric profile. This program allows the user to define an arbitrary path geometry in the atmosphere anywhere from the Earths surface to space. In its present form ionospheric effects are ignored. Its use is restricted to frequencies between 30KHzwavelength 10 km and 1500 Hz wavelength 0.2 m. For frequencies between 115 GHz wavelenth 0.25 cm and THz wavelength 20m,the model results should be accepted with caution. The model itself is unique in its flexibility of application and special numerical techniques which enable it to compute types of ray paths which some models cannot handle. Furthermore, the code is structured in a modular, top down fashion to allow for ease in modification and program maintenance. It has the capability to utilize user input atmospheric data or data from the USAFETAC archived weather tapes. Actual ray plotting is not provided. Instead, added information on the net atmospheric refractive effect such as range error is included in ouput along with a summary of the input parameters.
- Computer Programming and Software