Measurement and modeling of HF channel directional spread characteristics for northerly paths

Abstract

[1] The northerly ionosphere is a dynamic propagation medium that causes HF signals reflected from this region to exhibit delay spreads and Doppler shifts and spreads that significantly exceed those observed over midlatitude paths. Since the ionosphere is not perfectly horizontally stratified, the signals associated with each propagation mode may arrive at the receiver over a range of angles in both azimuth and elevation. Such large directional spreads may have a severe impact on radio systems employing multielement antenna arrays and associated signal-processing techniques since the signal environment does not comprise a small number of specular components as often assumed by the processing algorithms. In order to better understand the directional characteristics of HF signals reflected from the northerly ionosphere, prolonged measurements have recently been made over two paths: (1) from Svalbard to Kiruna, Sweden, and (2) from Kirkenes, Norway, to Kiruna. An analysis of these data is presented in this paper. The directional characteristics are summarized, and consideration is given to modeling the propagation effects in the form of a channel simulator suitable for the testing of new equipment and processing algorithms.

Radio communication via Near Vertical Incidence Skywave propagation: an overview

“…Wagner and Goldstein [45] are among the first to characterize the performance of the high-latitude ionospheric NVIS channel. Warrington et al [103] and Jodalen et al [104], amongst others, also provide a thorough channel analysis for high latitudes NVIS paths. Jodalen et al [104] presents the results from a propagation experiment over two NVIS paths in Northern Scandinavia using Doppler and Multipath SOunding Network (DAMSON) [105], with the aim of correlating the results of both paths.…”

“…Jodalen et al [104] presents the results from a propagation experiment over two NVIS paths in Northern Scandinavia using Doppler and Multipath SOunding Network (DAMSON) [105], with the aim of correlating the results of both paths. Warrington et al [103] presents direction finding measurements in Norway and Sweden, to better understand the directional characteristics of HF signals reflected in the high-latitude ionosphere. Lossman et al [106], who performed tests in the Baltic region, concluded that transmit frequencies greater than 5 MHz show higher effective data speeds due to the fact that man-made noise is mostly concentrated between 2 and 5 MHz.…”

Near real‐time input to a propagation model for nowcasting of HF communications with aircraft on polar routes

“…It was also found that the signals can arrive at the receiver over a range of directions with, for example, azimuthal standard deviations of up to 35° at frequencies of 2.8, 4.0, and 4.7 MHz being observed on one path from Isfjord, Svalbard to Alert, Canada [ Warrington , ]. Similar measurements have also been undertaken at auroral latitudes [ Warrington et al, ].…”

Near vertical incidence skywave

“…Wagner [1995] is one of the first to characterize the high-latitude ionospheric NVIS channel. Warrington [2006] and Jodalen [2000], amongst others, also provide a thorough channel analysis for high latitudes NVIS paths. Jodalen [2000] presents the results from a propagation experiment over two NVIS paths in northern Scandinavia using DAMSON (Doppler and Multipath Sounding Network), with the aim of correlating the results for both paths.…”

“…Jodalen [2000] presents the results from a propagation experiment over two NVIS paths in northern Scandinavia using DAMSON (Doppler and Multipath Sounding Network), with the aim of correlating the results for both paths. Warrington [2006] presents direction finding measurements in Norway and Sweden, to better understand the directional characteristics of HF signals reflected in the high-latitude ionosphere. Lossman [2011], who performed tests in the Baltic region, concluded that transmission frequencies greater than 5 MHz show higher effective data speeds due to the fact that man-made noise is mostly concentrated between 2 and 5 MHz.…”