Estimating Low-Latitude Scintillation Pattern Orientations and Irregularity Heights Using Measurements Made by a Local Array of Sensors

Ionospheric scintillation can significantly degrade L-band (~1–2 GHz) satellite communication and navigation signals. While the orientation of scintillation-induced signal intensity patterns has been studied, a past attempt struggled to fully account for its behavior (Kintner et al., 2004). To address this gap in knowledge, we investigated the orientation of low-latitude scintillation patterns using a local (< 1 km) array of low-cost Global Navigation Satellite System (GNSS)-based scintillation monitors (ScintPi). These radio sensors developed by Gomez Socola and Rodrigues (2022) were deployed at the Jicamarca Radio Observatory in Peru (11.97° S, 76.87° W, ~0° dip angle). We applied cross-correlation analyses of the received GNSS signal intensities to determine the directions along which scintillation fade patterns were elongated (Kintner et al., 2004). We then compared the experimental measurements to the results that would have been expected from the projection of magnetic field-aligned irregularities (Ledvina et al., 2004).
We found that the measured orientations were highly consistent (R=0.969) with those derived from a model of the projection of the geomagnetic field vector. Our results also indicate that approximations in the choice of B may explain discrepancies observed in previous modeling efforts (Kintner et al., 2004). Additionally, by analyzing residuals between measured orientations and those derived using B at different points along the receiver-satellite path, we demonstrate a method for estimating the altitude of the ionospheric irregularities responsible for scintillation. Preliminary results from multiple nights around the March Equinox suggest a mean irregularity height that is consistent with expected ionospheric conditions. These findings provide new insights into the spatial structure of low-latitude scintillation and offer encouragement for an alternative approach for estimating irregularity altitudes using GNSS signal observations.

References:

Kintner, P. M., Ledvina, B. M., de Paula, E. R., & Kantor, I. J. (2004). Size, shape, orientation, speed, and duration of GPS equatorial anomaly scintillations. Radio Science, 39(2).

Ledvina, B., Kintner, P., & de Paula, E. (2004). Understanding spaced-receiver zonal velocity estimation. Journal of Geophysical Research, 109.

Gomez Socola, J., Rodrigues, F.S. ScintPi 2.0 and 3.0: low-cost GNSS-based monitors of ionospheric scintillation and total electron content. Earth Planets Space 74, 185 (2022).

Acknowledgment:

This work was supported by NSF (AGS-1916055) and by an NSF GRFP fellowship.