Characterization of multi-scale ionospheric irregularities using ground-based and space-based GNSS observations

Abstract

Ionospheric irregularities can adversely affect the performance of Global Navigation Satellite System (GNSS). However, this opens the possibility of using GNSS as an effective ionospheric remote sensing tool. Despite ionospheric monitoring has been undertaken for decades, these irregularities in multiple spatial and temporal scales are still not fully understood. This paper reviews Virginia Tech’s recent studies on multi-scale ionospheric irregularities using ground-based and space-based GNSS observations. First, the relevant background of ionospheric irregularities and their impact on GNSS signals is reviewed. Next, three topics of ground-based observations of ionospheric irregularities for which GNSS and other ground-based techniques are used simultaneously are reviewed. Both passive and active measurements in high-latitude regions are covered. Modelling and observations in mid-latitude regions are considered as well. Emphasis is placed on the increased capability of assessing the multi-scale nature of ionospheric irregularities using other traditional techniques (e.g., radar, magnetometer, high frequency receivers) as well as GNSS observations (e.g., Total-Electron-Content or TEC, scintillation). Besides ground-based observations, recent advances in GNSS space-based ionospheric measurements are briefly reviewed. Finally, a new space-based ionospheric observation technique using GNSS-based spacecraft formation flying and a differential TEC method is demonstrated using the newly developed Virginia Tech Formation Flying Testbed (VTFFTB). Based on multi-constellation multi-band GNSS, the VTFFTB has been developed into a hardware-in-the-loop simulation testbed with external high-fidelity global ionospheric model(s) for 3-satellite formation flying, which can potentially be used for new multi-scale ionospheric measurement mission design.

Leveraging the CYGNSS Spaceborne GNSS‐R Observations to Detect Ionospheric Irregularities Over the Oceans: Method and Verification

“…In on the ROTI index in TECU/min, where 10 16 electrons/m 2 = 1 TEC unit (TECU). As we can see, since the ROTI index is derived from standard GNSS dual-frequency phase data collected using geodetic GNSS receivers, the observations are mainly distributed over terrestrial areas (Pi et al, 2013;Yang & Liu, 2017), which is similar to the above-mentioned ionograms observed by the ionosondes.…”

“…The resulting ionospheric irregularities of the plasma density could significantly cause rapid fluctuations in the intensity, phase, angle of arrival, and direction of trans‐ionospheric radio signals at frequencies <3 GHz in a stochastic manner (Guo et al., 2019; Yuan & Ou, 2001). Further, they would influence the performance of high‐precision devices and applications which include global navigation satellite systems (GNSS) (Luo et al., 2020; Peng et al., 2021; Sreeja et al., 2020; Yuan, 2002; Zhang et al., 2022). Therefore, monitoring or forecasting the equatorial ionospheric irregularities is becoming an essential space weather science issue and also is crucial for the anti‐interference ability, high reliability, and high integrity of GNSS service applications, especially in autonomous driving and air traffic.…”

Investigating the Effects of Ionospheric Scintillation on Multi‐Frequency BDS‐2/BDS‐3 Signals at Low Latitudes

“…Ionospheric amplitude scintillation commonly occurs when the Fresnel dimension of the propagating radio wave signal is of the order of irregularity scales in the ionosphere. This condition is met for the post‐sunset equatorial irregularities formed in equatorial F‐spread and equatorial plasma bubbles (EPBs; Li et al., 2021; Patel et al., 2009; Y. Peng et al., 2021; Yokoyama & Stolle, 2017). Considering that the Brazilian region is one of the most affected by ionospheric scintillation for all GNSS‐based services (Carmo et al., 2022; Moraes et al., 2012; Salles et al., 2021; Vani et al., 2017), the ISMR data in this study were collected at four GNSS sites distributed over the Brazilian territory, including STAR, STCB, STMC, and STBR.…”

Analysis of the architecture of the hardware and software complex for ground-based ionosphere radiosounding

“…Efforts on the design and creation of ionospheric remote sensing systems using short wave signals can go in several ways, in particular, along the way of creating tools for detailed analysis, study with the identification of the main defects that occur when weak signals are isolated, all kinds of interference, etc. In addition, such scientific developments may follow the path of creating means of conducting operations with large amounts of information, which implies the search for hidden opportunities to improve the applied analysis techniques [3]. The statistical data arrays collected as a result are of significant value from the standpoint of the prospects for their subsequent use to create a highquality architecture of a hardware and software complex for groundbased ionosphere radiosounding, which would allow forecasting the corresponding parameters of the ionosphere and ionospheric radio lines in the future [4].…”