Ionospheric Doppler and echo phase measured by the Wuhan Ionospheric Oblique Backscattering Sounding System

Abstract

[1] Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) is a highfrequency (HF) sky wave over-the-horizon radar developed for ionospheric research and HF channel management. This radar, located in Wuhan (30.35°N, 114.33°E) has been under construction by the Ionosphere Lab of Wuhan University since 2002. WIOBSS uses long coded pulses and pulse compression to achieve good sensitivity and measures the bitemporal ionospheric response, channel scattering function, and phase of echoes simultaneously and then displays the processed data as ionograms and Dopplionograms in real time. Bitemporal ionospheric response is a matrix composed of the ionospheric transmission function with delay and time variables, while the scattering function shows the spectrum of the received signals as a function of the delay and Doppler coordinates, and is obtained by the Fourier Transform of the bitemporal ionospheric response over the time variable. The application of pulse compression and coherent integration allows WIOBSS to measure ionospheric Doppler with high resolution and very low power. A method is developed to get phase data directly from the bitemporal ionospheric response. The measured phase is strung in a series and then divided into linear and nonlinear components. The angular frequency of the linear component is in direct proportion to ionospheric Doppler velocity while the fluctuation of the nonlinear component includes the information of Doppler velocity spread. The phase method based on pulse impression is able to obtain the statistic Doppler information from weak backscattered echoes in short detection time.

Enhancement and HF Doppler observations of sporadic‐E during the solar eclipse of 22 July 2009

“…The parameters of operating frequency, height bins from 65 to 800 km with 3.84 km step and echo signal‐to‐noise ratio (SNR) compose the ionogram, from which the virtual height and the critical frequency of the detected ionosphere can be obtained. The Wuhan ionospheric oblique backscatter sounding system (WIOBSS) was placed in Wuhan to transform the phase‐coded pulse train to the east at the frequencies 6.6, 8.2, and 10.6 MHz [ Chen et al , 2007]. Every 1 min the WIOBSS detected the ionosphere at these three frequencies.…”

An approach to correction of ionospheric phase contamination in HF skywave radar systems

“…However, the movement of ionosphere layer produces ionospheric frequency modulation which causes significant spreading of both the surface clutter and the echoes of target in Doppler domain. This greatly limits the target detection performance of OTHR [2], [3].…”

A new inversion algorithm for backscatter ionogram and its experimental validation

“…The principal specifications of WIOBSS are given in Table 1. The detailed description of WIOBSS is given in Chen et al (2007) and Zhou et al (2010). To test and verify the accuracy of the inversion method, an ionospheric vertical incident sounder was located in the coverage of the backscatter radar.…”

“…This technique utilizes the simulated annealing method to obtain the global optimum solver, which is found to be stable and fast. This method has been validated on real data collected by the Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) (Chen et al, 2007;Zhou et al, 2010). To validate the inversion method proposed in this study, we carry out three representative experiments with the antenna directing southward, westward, and northwestward, respectively.…”