Xiao Cui

Design of an Ultrawideband Ionosonde

In this letter, an ultrawideband ionospheric sounding system was designed for ionospheric research and communication channel management. The frequency band of this ionosonde ranges from high frequency to very high frequency. It can be flexibly used at both monostatic and bistatic stations as a GPS receiver module was integrated. The system design includes three major components: control system, transmitting system, and receiver system. The operational parameters, such as frequency, waveform, and modulation type, can be manually reset. Correlation and Fourier algorithms are used to obtain a high signal-to-noise ratio and enlarge the detection range. The typical experimental results demonstrate that the proposed system can be used to study the ionosphere effectively.

The hardware design of a new ionospheric sounding system

The ionospheric sounding system is a type of high-frequency over-the-horizon skywave radar developed for ionospheric research and HF channel management. The hardware system of a portable low-power multifunctional ionospheric sounding system is presented in this paper. The device can be used for typical ionospheric sounding and spectrum monitoring at monostatic and bistatic station. The system structure and the primary module are depicted in detail. Typical experimental results demonstrate that the design of this device is successful for ionospheric researching.

Design and Application of Wuhan Ionospheric Oblique Backscattering Sounding System with the Addition of an Antenna Array (WIOBSS-AA)

The Wuhan Ionospheric Oblique Backscattering Sounding System with the addition of an antenna array (WIOBSS-AA) is the newest member of the WIOBSS family. It is a multi-channel radio system using phased-array antenna technology. The transmitting part of this radio system applies an array composed of five log-periodic antennas to form five beams that span an area to the northwest of the radar site. The hardware and the antenna array of the first multi-channel ionosonde in the WIOBSS family are introduced in detail in this paper. An ionospheric detection experiment was carried out in Chongyang, Hubei province, China on 16 March 2015 to examine the performance of WIOBSS-AA. The radio system demonstrated its ability to obtain ionospheric electron density information over a wide area. The observations indicate that during the experiment, the monitored large-area ionospheric F2-layer was calm and electron density increased with decreasing latitude.

Application of Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) for Sea-State Detection

To combine the advantages of long detection range and small antenna array, the newly designed Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) transmits radio waves by ionospheric reflection and receives oceanic backscattered ground waves. To combine the functions of operating frequency selection and sea-state detection, WIOBSS can transmit the interpulse coding wave and frequency-modulated continuous wave waveforms in one hardware platform. The hardware and software of the radio system are introduced. A sky-wave over-the-horizon sea-state detection experiment was carried out in Chongyang and Longhai, China, on January 28, 2015. The observations of the oceanic surface echoes 130-300 km from the coastline are also presented.

MST Radars of Chinese Meridian Project: System Description and Atmospheric Wind Measurement

Based on the construction of the Chinese Meridian Project, two mesosphere, stratosphere, and troposphere (MST) radars were designed and located in Beijing and Chongyang, Hubei province, China, to investigate the atmospheric dynamics in the troposphere, stratosphere, and mesosphere. The official names of the two radio systems are Beijing MST radar and Wuhan MST radar. They are the monostatic radars with an active phased antenna array consisting of 576 Yagi antennas and operated by a 53.8-MHz frequency. The three-element Yagi antennas are arranged in a square grid of 96-m side length to form the aperture of 9216 m2. This antenna array arrangement forms the five symmetric radar beams of vertex, east, west, south, and north. The beamwidth is 3.2°, the maximum directive gain is 34.8 dB, and the total transmitting peak power is ~172 kW. The zenith angle of the oblique beams is adjustable between 0 and 20° with a 1° step. The average power aperture product of the radars is 3.2×108 Wm2. There are three operating modes of the MST radars, including the low, middle, and high modes, applied to observe the troposphere, stratosphere, and mesosphere, respectively. Thus, these two coherent pulse Doppler MST radars have the ability to study the features of the midlatitude atmospheric turbulence and wind field vector from the troposphere to the lower thermosphere with high spatiotemporal resolution. In this paper, the antenna array, system hardware, and signal processing methods, as well as the typical observation results of the troposphere, stratosphere, and mesosphere, are introduced.

Comparison of the Traditional Ionosonde and the Digital Ionosonde Based on Direct Digitization

A new digital ionosonde based on direct digitization has been developed in the Electronic Information School of Wuhan University. There is no stage of frequency translation between the baseband and the radio frequency, and the realization of the direct digitization greatly simplifies the architecture to achieve optimized design. It is compared with the traditional ionosonde with superheterodyne architecture on various aspects, such as hardware structure, signal processing, system parameters, and experimental results. In the end, there is a summary of the comparison and the envisagement of the digital ionosonde.