Measured channel parameters for the disturbed wide‐bandwidth HF channel

Abstract

The wideband HF (WBHF) channel impulse response measurements presented here were taken over a high‐latitude auroral path using the MITRE experimental WBHF test facility. A nominal instantaneous bandwidth of 1 MHz was used for the majority of the tests. These tests took place from 14 March through 1 April 1992 over a path from Sondrestrom AFB, Greenland, to Bedford, Massachusetts, a distance of approximately 3,100 km. The measurements were made using a direct‐sequence pseudo‐noise (DSPN) channel probe with a (±180°) chip modulation and chip rate of 1024 kchips/second. Complex channel impulse response values at increments of 500 nanoseconds in delay were derived by correlating the received signal with a set of local DSPN references uniformly spaced in delay over a delay range of 2 ms. Each of these channel impulse response values was sampled in time at a rate of up to 62.5 samples per second, resulting in the ability to observe (one‐sided) Doppler spectra and shifts of up to 31.25 Hz. From these measurements, the channel scattering function, rms (2σ) Doppler spread, rms (2σ) Delay spread, Doppler shift, and rms (2σ) spread factor were calculated. In addition, for the first time, the impulse response correlation along the delay axis was calculated. These latter measurements support the use of an uncorrelated scattering hypothesis in modeling the disturbed WBHF channel.