Simulating the effects of scintillation on transionospheric signals with a two‐way phase screen constructed from ALTAIR phase‐derived TEC

Abstract

Severe scintillation on transionospheric radio signals caused by small‐scale plasma irregularities can greatly disrupt wideband communication, surveillance, and navigation systems. Development of techniques to mitigate the effects of scintillation requires accurate characterization of the ionospheric propagation channel. To achieve this goal, multiple campaigns were conducted as part of the joint U.S. ‐UK Wideband Ionospheric Distortion Experiment to obtain ionospheric signatures from various instruments located on Kwajalein Atoll. We use tracking data from the VHF/UHF Advanced Research Project Agency Long‐Range Tracking and Instrumentation Radar for overflights of passive calibration spheres in low‐Earth orbit to demonstrate the validity of a one‐dimensional (1‐D) phase screen model to represent the propagation channel through a disturbed ionosphere. The 1‐D phase screen is constructed from radar phase‐derived estimates of the total electron content. We present a detailed comparison of simulated radar cross section after propagation through the phase screen with observed radar returns under both disturbed and quiet ionospheric conditions. Successful reproduction of radar amplitude enhancements and fades adds to our understanding of small‐scale plasma irregularities and moves us toward our goal of providing precise predictions of radar system performance. Doing so will allow for the development of better mitigation/compensation algorithms for detrimental ionospheric effects. Result from this study also provide an assessment of the tools required for incorporating in situ density measurements along with phase screen theory into situational awareness products to offer an accurate nowcast/forecast of system impacts to users in the communication, navigation, and surveillance communities.