Automated System for High Rate GNSS Data Processing with Swarm Conjunctions

Scintillation is a phenomenon that occurs on Global Navigation Satellite Systems (GNSS) signals, which are critical to various industries that use GNSS services. One specific effect that occurs is signal fading and loss of lock. This interrupts a user’s ability to use GNSS for tracking. During severe scintillation events, GNSS systems for aircraft can have reduced service. Thus, it is important to learn more about scintillation. However, scintillation can also be used to characterize space weather irregularities. A study of these irregularities is important as they can help increase the understanding of how a space weather event will cause scintillation and the effect it has on GNSS.

To understand and characterize irregularities in the ionosphere, the Scintillation Auroral GPS Array (SAGA) located at Poker Flat Research Range, Alaska is used. SAGA is an array of multiple L1 and L2C GNSS receivers. The data from SAGA during a scintillation event can be used to characterize the ionospheric irregularity layer, including velocity, thickness, and the top height of the irregularity layer. Previous researchers developed methods for estimating these properties based on high-rate (100 Hz) signal power and phase data. However, these researchers have only studied specific scintillation events.

In this work, for the first time, we survey a large number (~1000) of scintillation events from various SAGA campaigns and show their distributions of velocity, top height, and thickness. The initial findings from the high-rate analysis of the SAGA data show that, as the velocity of these irregularities increases, the top height increases. Second, it appears that as velocity increases the thickness of the irregularity decreases. To validate these results, Swarm data will be used for analysis. We will compare the velocity results from our SAGA estimations of irregularity properties to the Swarm satellite system, from the Thermal Ion Imagers (TII) in situ velocity measurements. Data from Swarm A and B satellites will be used due to satellite A flying at about 460 km and satellite B flying at about 510 km. Swarm carries two TII sensors orientated vertically and horizontally. For this study, only the cross-track velocities from the horizontal sensor will be used.