TRIDENT: Advancing ionospheric disturbance detection with next-gen HF sounders

Ian Collett, Ionospheric Scientist 

Understanding Earth’s ionosphere and how it responds to natural and human-induced phenomena has become increasingly critical in today’s interconnected world. 

Among the most significant phenomena are traveling ionospheric disturbances (TIDs). Gravity waves triggered by earthquakes, thunderstorms and rocket launches contribute to these disturbances. As they ripple through the ionosphere with varying intensity, they wreak havoc on communications infrastructure, GPS and radar. 

At Orion, we address these disruptions head-on with cutting-edge computational innovation: TRIDENT, the Traveling Ionospheric Disturbance Evaluation Tri-wave sensor. Built on decades of high- frequency (HF) sounding expertise, TRIDENT represents the next-generation of ionospheric monitoring. The system improves upon its predecessor, the TID Detector Built in Texas, or TIDDBIT, with novel features like frequency-modulated continuous wave signaling, expanded receiver networks and advanced data processing algorithms. 

TRIDENT delivers more than hardware innovation—it changes how scientists collect and analyze ionospheric disturbances. 

A BREAKTHROUGH IN TID CHARACTERIZATION 

TRIDENT’s most significant advancement is its ability to detect and analyze TIDs with unmatched precision. At the center of the system is an advanced algorithm that uses a sophisticated technique called the N-Dimensional Lomb-Scargle Periodogram. Although complex, the takeaway is simple: this is the first time this advanced analytical tool has been applied to HF Doppler data, which enables TRIDENT to identify and study multiple disturbances simultaneously.  

Early simulations have already demonstrated accuracy in measuring TID characteristics, such as size, direction and behavior. These insights can improve predictions for disruptions that affect GPS, communication networks and radar systems. 

WHY IT MATTERS 

Traditional HF-sounding methods have made significant strides in ionospheric monitoring, but they still face limitations. Existing systems often have difficulty analyzing multiple TIDs simultaneously and inaccuracies can occur in assigning wave positions. TRIDENT’s combination of advanced algorithmic processing and enhanced sensor configurations addresses these gaps, allowing for more robust and accurate modeling of TID behaviors.  

TRIDENT helps us understand TID behavior, which allows us to mitigate their impact on technological systems like HF communications and Global Navigation Satellite System (GNSS). Additionally, TRIDENT pushes beyond disturbance detection by using TID measurements to identify their sources. For example, rocket launches often generate TIDs, and analyzing these disturbances could help estimate the trajectory or timing of the launch. 

This breakthrough isn't just an academic achievement; it's a crucial step forward for industries and applications that rely on HF communications and GNSS, including aviation, national defense and space weather forecasting. As TID data becomes integrated into regional ionospheric models, organizations will gain the tools to predict and mitigate the impacts of ionospheric disturbances on critical technologies.  

WHAT’S NEXT 

Orion expects to deploy the full TRIDENT system in 2026, and our engineers are already conducting rigorous simulations to refine its capabilities. Testing the algorithm against real-world TID events and incorporating additional data sources, such as angle-of-arrival and group range measurements, will further enhance its accuracy and versatility.  

Our goal is to provide the scientific and operational community with transformative insights into the ionosphere’s behavior, and help build smarter, more resilient global systems.  

As we look ahead, TRIDENT represents more than a technical milestone but a commitment to understanding and adapting to the complex dynamics between our planet, its atmosphere, and the technologies that rely on them. By advancing TID characterization and ionospheric monitoring, we’re opening new frontiers in science and operations, ensuring the systems we depend on continue to thrive in an ever-changing environment.  

ABOUT THE AUTHOR 

Dr. Ian Collett is a senior research scientist at Orion, specializing in radio frequency remote sensing of the ionosphere. His expertise spans HF through L-band frequencies, signal processing and data science. He leads Orion's development of HF algorithms for TRIDENT and serves as principal investigator for Orion’s work on the IARPA SINTRA program.