Tropospheric Scintillation Signatures: Observations of the Possible Effect Thunderstorms have on GPS Signals

The Global Navigation Satellite System (GNSS) has wide applications from daily life to numerous industries. Understanding how space weather affects the radio signals is imperative to maintain its accuracy. Space weather events, such as geomagnetic storms, create a disturbance in the ionosphere by increasing the total electron content. However, these disturbances are found in high latitude regions where most studies are conducted; minimal research exists concerning the mid-latitude region. There is a gap in research focusing on how tropospheric sources such as thunderstorms might generate ionospheric structures that affect these signals as well. The purpose of this project is to fill that gap by analyzing the possible relationship between thunderstorms and scintillation. If a relationship is found, this could spark a whole new method of potentially predicting severe weather such as tornadoes and hurricanes. To study these relationships, 2 GPS receivers, both situated in Daytona Beach, Florida, were used to record GNSS data. A code was developed that graphed and analyzed the receiver data for scintillation signatures. Archived weather data was used to identify the exact date and time of thunderstorms. After favorable scintillation candidates were found, lightning location data was combed to compare it with the scintillation signatures. More accurate lightning data is required to determine a direct correlation to GPS scintillation, however, the current work lays a foundation to study relationship between tropospheric events and radio signal scintillation

Investigating the Correlation between GNSS Signal Scintillation and Thunderstorms

Global Navigation Satellite Systems (GNSS) have wide application in multiple sectors from daily life to industrial use. These sectors include navigation, timing, and positioning which all require a constant stream of accurate data. One aspect of maintaining the accuracy involves a deep understanding of the ionosphere and how it affects radio signals. This project takes into account an element that might impact the ionosphere: thunderstorms and their high-altitude lightning. Structures created in the ionosphere can cause scintillations, but finding if thunderstorms could initiate these structures is the main goal. Scintillation refers to fluctuations in the phase and amplitude of GNSS signals. There are some forms of lightning, such as blue jets and sprites, that have the ability to reach the ionosphere. This high-altitude lighting is thought to mostly occur in the tropics because of favorable conditions, but it has been observed in other latitudes. Lightning is shown to reach and affect the upper atmosphere, but the effect this could have on satellite signals is still under review. To record relevant scintillations, GNSS receivers have been situated in Daytona Beach, FL and the weather has been monitored for thunderstorms around the area. Receiver data is then graphed and analyzed for significant scintillations during the times of thunderstorms. Lightning location and time is also overlaid on a map with the satellite location plotted to further prove possible correlation between GNSS scintillations and lighting strikes. An evident correlation between scintillation signals and lightning strikes has been observed, but more evidence is needed to confirm this lightning could be the cause of the scintillation

Total Electron Content and Ionospheric Scintillation Measurements during the Total Solar Eclipse of July 2, 2019

Global Navigation Satellite Systems (GNSS) provide a reliable source of radio wave signals that is available at all times throughout the entire planet. These signals are known to also interact with the ionosphere, where there is a high concentration of free electrons and ions. This in turn creates a framework for scientists to continuously monitor and analyze how these signals are affected by free electron and ion concentration irregularities in this region. Such irregularities may induce fluctuations in both signal amplitude and phase known as ionospheric scintillations. The behavior of the ionosphere is also known to be directly related with solar activity as well as localized phenomena, such as solar eclipses. This study aims to measure the impact of the solar eclipse of July 2, 2019 on local ionospheric properties in terms of total electron content (TEC) and scintillation indices S4 and SigmaPhi. Two GNSS receivers (NovAtel GPStation-6) were stationed in La Serena, Chile in collaboration with the University of La Serena and in Cerro Pachón, Chile along the Andes Lidar Observatory, where they collected TEC and scintillation data prior, during and after totality. We have observed a pronounced drop and recovery of TEC on both stations as well as supporting high rate data to explore possibilities of eclipse induced scintillations

Additively Manufactured Morphing Structures with Embedded Smart Actuators

Observing volant creatures has demonstrated that adapting the shape of the wing to the changing flight environment increases flight efficiency and performance. Current aerial vehicles have stiff aerodynamic surfaces that limit any adapting capability. The development of the concept of fully morphing structures is enabling the creation of bio-inspired, adaptable structures with outstanding performance. However, current morphing structures suffer from poor implementation that often brings more drawbacks than advantage to the final product. This research focuses on an effective implementation of morphing technology to fully realize it\u27s potential. This can be achieved by employing a novel additive manufacturing method that can fabricate morphing structures with integrated and distributed actuation systems. Dielectric elastomer actuators (DEAs) are one of the most intensively studied soft, smart actuators due to their promising electromechanical properties. As such, this project utilizes DEAs as the primary material for the morphing structure. Preliminary work has been completed in selecting and validating the additive manufacturing method as well as material selection and improvement. The main goal of this research is to implement additive manufacturing coupled with morphing structures to design, build and test a fully morphing wing structure suitable for small aerial vehicles

Investigation into the G1 Geomagnetic Storm of January 31st, 2019 through GNSS data processing.

Ionospheric scintillation are signal perturbations caused by the interaction between the Earth’s geomagnetic field and the Sun’s activity and are apparent through rapid modifications in radio waves. Such perturbations are the most prevalent source of uncertainties in the position solution for Global Navigation Satellite Systems (GNSS). Since GNSS provide essential services for multiple industries and even everyday life, understanding ionospheric scintillation is essential. Geomagnetic storms are known to create disturbances in the ionosphere by increasing the total electron content (TEC). Therefore, this project highlights the relationship between geomagnetic storms and ionospheric scintillation through the analysis of processed GNSS data and proposes techniques for the identification and classification of scintillation in the mid-latitude region. Utilizing phase and amplitude data collected from two GPS Receivers installed in Daytona Beach, FL, possible events that correlate with scintillation observed during the storm were studied. A GI minor geomagnetic storm, measured to be -10 nanoTesla, that took place on January 31st, 2019 was studied because a significant spike in both phase and amplitude was observed. The implementation of machine learning is also explored through the development of an unsupervised k-means clustering algorithm that will identify the distribution of data points and classify scintillation

Additively manufactured unimorph dielectric elastomer actuators: Design, materials, and fabrication

Dielectric elastomer actuator (DEA) is a smart material that holds promise for soft robotics due to the material’s intrinsic softness, high energy density, fast response, and reversible electromechanical characteristics. Like for most soft robotics materials, additive manufacturing (AM) can significantly benefit DEAs and is mainly applied to the unimorph DEA (UDEA) configuration. While major aspects of UDEA modeling are known, 3D printed UDEAs are subject to specific material and geometrical limitations due to the AM process and require a more thorough analysis of their design and performance. Furthermore, a figure of merit (FOM) is an analytical tool that is frequently used for planar DEA design optimization and material selection but is not yet derived for UDEA. Thus, the objective of the paper is modeling of 3D printed UDEAs, analyzing the effects of their design features on the actuation performance, and deriving FOMs for UDEAs. As a result, the derived analytical model demonstrates dependence of actuation performance on various design parameters typical for 3D printed DEAs, provides a new optimum thickness to Young’s modulus ratio of UDEA layers when designing a 3D printed DEA with fixed dielectric elastomer layer thickness, and serves as a base for UDEAs’ FOMs. The FOMs have various degrees of complexity depending on considered UDEA design features. The model was numerically verified and experimentally validated through the actuation of a 3D printed UDEA. The fabricated and tested UDEA design was optimized geometrically by controlling the thickness of each layer and from the material perspective by mixing commercially available silicones in non-standard ratios for the passive and dielectric layers. Finally, the prepared non-standard mix ratios of the silicones were characterized for their viscosity dynamics during curing at various conditions to investigate the silicones’ manufacturability through AM

Investigation into Geomagnetic storms and ionospheric scintillation

Understanding how space weather phenomenon affects daily life has been a main focus of space weather studies. In particular, identifying the relationship between solar activities, ionospheric irregularities and consequently ionospheric scintillation has inspired numerous research efforts. Geomagnetic storms fueled by solar activities cause ionospheric irregularities. Ionospheric scintillation occurs when radio signals travel through these irregularities and experience rapid fluctuations in radio signal phase and amplitude. Such fluctuations have great consequences in radio wave based technology such as the Global Position system(GPS) as it causes a loss of lock. Therefore, through the implantation of two GPS Receivers, continuous data was obtained on phase and amplitude of radio signals from the Global Navigation Satellite Systems(GNSS). This data was then thoroughly analyzed to identify scintillation signatures. On January 31st, 2019, scintillation signatures that correlated to a G1 minor geomagnetic storm were observed. In this paper, the method of analysis is adapted from the aforementioned case study to identify past geomagnetic events that possibly correlated with observed scintillation. Through this study, it is hoped that a correlation between geomagnetic storms and ionospheric scintillation in the mid-latitude region will be highlighted

Effects of Ferroelectric Fillers on Composite Dielectric Elastomer Actuator

Integrating nano- to micro-sized dielectric fillers to elastomer matrices to form dielectric composites is one of the commonly utilized methods to improve the performance of dielectric elastomer actuators (DEAs). Barium titanate (BaTiO3) is among the widely used ferroelectric fillers for this purpose; however, calcium copper titanate CaCu3Ti4O12 (CCTO) has the potential to outperform such conventional fillers. Despite their promising performance, CCTO-based dielectric composites for DEA application are studied to a relatively lower degree. Particularly, the composites are characterized for a comparably small particle loading range, while critical DEA properties such as breakdown strength and nonlinear elasticity are barely addressed in the literature. Thus, in this study, CCTO was paired with polydimethylsiloxane (CH3)3SiO[Si(CH3)2O]nSi(CH3)3 (PDMS), Sylgard 184, to gain a comprehensive understanding of the effects of particle loading and size on the dielectric composite properties important for DEA applications. The dielectric composites’ performance was described through the figures of merit (FOMs) that consider materials’ Young’s modulus, dielectric permittivity, and breakdown strength. The optimum amounts of the ferroelectric filler were determined through the FOMs to maximize composite DEA performance. Lastly, electromechanical testing of the pre-stretched CCTO-composite DEA validated the improved performance over the plain elastomer DEA, with deviations from prediction attributed to the studied composites’ nonlinearity

Callaghan, Fergal

Our work is to build a versatile chamber that is capable of allowing experiments for any component needed in an advanced life support system while maintaining a much lower cost compared to a similar commercial product. We plan to use the chamber for conducting experiments on living plants and microbial life in a stable environment. These experiments will further research toward a bio-regenerative life support system capable of allowing humans explore beyond Earth. Our system is designed to control temperature, atmospheric composition, air flow, ambient pressure, water distribution, and light intensity. With these factors, the experiments can more closely mimic the environment of Mars, test the ability of an aeroponics growth system for plants, or even use a previously built-in-house clinostat to achieve hypogravity testing. Beyond our own research, the team will be working towards commercializing the device as it is needed for most experiments to ensure a consistent environment