Session B5: Receiver Design, Signal Processing, and Antennas

Optimizing High-Rare Scintillation Data Downlinks in Radio Occultations
Tibor Durgonics, NOAA SWPC / CIRES; Paul Strauss, Margaret Chen, Endawoke Yizengaw, The Aerospace Corporation; Jun Wang, CIRES; Dominic Fuller-Rowell, NOAA SWPC / CIRES; Tzu-Wei Fang, NOAA SWPC
Location: Beacon B

This study investigates the effectiveness of an onboard trigger algorithm used to downlink high-rate radio occultation (RO) data for ionospheric scintillation monitoring. The algorithm, originally developed for COSMIC-2, relies on the S4 amplitude scintillation index calculated onboard from signal-to-noise (SNR) measurements to determine when to downlink high-rate data. Concerns arose regarding its suitability for high-latitude RO data, where scintillation might manifest primarily as phase variations.
Analysis of COSMIC-2 data confirmed the algorithm's effectiveness at low latitudes, and found no significant phase scintillation without accompanying amplitude scintillation. However, data from commercial RO providers (PlanetiQ and Spire) during a 3-day campaign period revealed a substantial portion of high-latitude tracks exhibit significant phase scintillation despite low S4 values. This suggests the current S4-based trigger might miss critical high-latitude scintillation events.
The study recommends further investigation using a larger dataset and exploring additional criteria beyond S4, such as based on the phase scintillation index. The possibility of residual data anomalies also requires consideration. Future data pilots and longer observation periods will be crucial for refining the trigger algorithm and establishing optimal thresholds for operational needs.