Generalized Force Approach to Point-to-Point Ionospheric Ray Tracing and Systematic Identification of High and Low Rays

Abstract

A variant of the direct optimization method for point-to-point ionospheric ray tracing is presented. The method is well suited for applications where the launch direction of the radio wave ray is unknown, but the position of the receiver is specified instead. Iterative transformation of a candidate path to the sought-for ray is guided by a generalized force, where the definition of the force depends on the ray type. For high rays, the negative gradient of the optical path functional is used. For low rays, the transformation of the gradient is applied, converting the neighbourhood of a saddle point to that of a local minimum. Knowledge about the character of the rays is used to establish a scheme for systematic identification of all relevant rays between given points, without the need to provide an accurate initial estimate for each solution. Various applications of the method to isotropic ionosphere demonstrate its ability to resolve complex ray configurations including threedimensional propagation and multi-path propagation where rays are close in the launch direction. Results of the application of the method to ray tracing between Khabarovsk and Tory show good quantitative agreement with the measured oblique ionograms.

Vehicular Channel Characterization in Urban Environment at 30 GHz considering Overtaking and Traffic Flow

“…The results generated from RT simulations of interior scenes for a penetrable hollow wedge formed by multilevel walls can correspond to that of the 3D full wave [29]. [30] presented many kinds of methods for direct optimization with regard to point-to-point ionospheric RT. Users can generate their own channel according to their own needs by reconstructing the 3D model of the scenario and setting up simulation parameters (frequency, antenna pattern, etc.)…”