Leveraging Geodetic GPS Receivers for Ionospheric Scintillation Science

Abstract

We demonstrate scintillation analysis from a network of geodetic Global Positioning System (GPS) receivers which provide data at 1-second resolution. We introduce proxy phase (σ TEC) and amplitude (SNR 4) scintillation indices and validate them against the rate of change of TEC index (ROTI) and S 4. Additionally, we validate scintillation observations against a Connected Autonomous Space Environment Sensor scintillation receiver. We develop receiver-dependent scintillation event thresholding using hardware-dependent noise variance. We analyze 6 days adjacent to the 7-8 September 2017 geomagnetic storm, using 169 receivers covering magnetic latitudes between 15 • and 65 • in the American longitude sector. We leverage the available spatial sampling coverage to construct 2-D maps of scintillation and present episodic evolution of scintillation intensifications during the storm. We show that low-latitude and high-latitude scintillation morphology match well-established scintillation climatology patterns. At midlatitudes, spatiotemporal evolution of scintillation partially agrees with known scintillation patterns. Additionally, the results reveal previously undocumented midlatitude scintillation-producing structures. The results provide an unprecedented view into the spatiotemporal development of scintillation-producing plasma irregularities and provide a resource to further exploit scintillation evolution at large spatial scales.

Extreme Low‐Latitude Total Electron Content Enhancement and Global Positioning System Scintillation at Dawn

“…We use computed scintillation indices to produce 2D maps of scintillation occurrence and strength. Due to the hardware limitations, we use Total Electron Content (TEC) to derive phase scintillation index σ T EC (Beach & Kintner, 1999;Mrak et al, 2020), and amplitude scintillation index SN R 4 derived from signal-to-noise ratio (SNR). While the former is defined in the same manner as the conventional phase scintillation index (σ Φ ) using a moving standard deviation window over 1 minute, the latter is computed in the same manner.…”

“…While the former is defined in the same manner as the conventional phase scintillation index (σ Φ ) using a moving standard deviation window over 1 minute, the latter is computed in the same manner. The conventional normalization by mean intensity is avoided for the reasons discussed by Mrak et al (2020).…”

“…We use a receiver-dependent threshold for scintillation indices, thereby only values 2.5 times above the receiver noise floor are used (cf. Mrak et al, 2020). We use the traditional scintillation index S 4 on a single receiver to demonstrate the scintillation intensity.…”

“…The biggest storm of solar cycle 24, the 2015 St. Patrick's storm, elevated the morning EIA crests by 150-350%, while the crests were confined to 20 • MLAT (Astafyeva et al, 2015). For reference, a preliminary survey for pre-dawn GPS scintillations using the same dataset (Mrak et al, 2020) in the years 2012 -2019 revealed that this particular storm was the only such event in the American longitude sector.…”

On the Properties of and Ionospheric Conditions Associated With a Mid‐Latitude Scintillation Event Observed Over Southern United States

“…Adequate observations of ionospheric scintillation, however, require measurements of amplitude and/or phase of the probing radio signals at a high rate, typically >10 Hz. While a large number of geodetic GPS receivers exist and their observations are made publicly available, they only provide observables at a lower sampling rate, usually at 1/30 Hz and more recently at 1 Hz (Mrak et al, 2020). While geodetic receivers can provide some indication of the occurrence of ionospheric irregularities and potential scintillation (Bhattacharyya et al, 2000;Luo et al, 2020;Mrak et al, 2020;Pi et al, 1997), high rate measurements are needed for proper specification of scintillation (Beach & Kintner, 1999).…”