TY - Generic T1 - Toward Developing an Algorithm for Separation of Transmitters of High Frequency Chirp Signals of Opportunity for the Purpose of Ionospheric Sounding T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Simal Sami A1 - Nisha Yadav A1 - Nathaniel A. Frissell A1 - Robert Spalletta A1 - Declan Mulhall A1 - Dev Raj Joshi A1 - Juha Vierinen JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Web-Based Application for the Visualization and Analysis of Ionogram Data Observed by GNU Chirpsounder2 T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Nisha Yadav A1 - Simal Sami A1 - Dev Raj Joshi A1 - Nathaniel A. Frissell A1 - Robert A. Spalletta A1 - Paul M. Jackowitz A1 - Juha Vierinen AB -

The focus of my system is to develop a web-based application for the visualization and analysis of data observed by GNU Chirpsounder2. We receive many ionograms each day from different transmitters around the world. Currently, data is in an unsorted format, so my initial task is to classify ionograms by chirp-rate and distance of the transmitter from the receiver. Once these two parameters are identified, it is necessary to have a method for sorting, analyzing, and visualizing the collected ionograms to conduct scientific studies or make the observations useful for radio communications operations.

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Mid-latitude Irregularities Observed by the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Dev Raj Joshi A1 - Nathaniel A. Frissell A1 - Juha Vierinen AB -

The spread in the echoes of high-frequency (HF, 3-30 MHz) radio waves from the F-region of the ionosphere was one of the earliest indications of plasma density irregularities in the mid-latitude F region ionosphere. Although mid-latitude spread F has been widely studied, the plasma instability mechanisms that create these irregularities are still largely unknown. This phenomenon can cause radio wave scintillation effects that degrade the performance of human-made technologies such as satellite communications and Global Navigation Satellite Systems (GNSS). Here, we present signatures of mid-latitude irregularities observed in oblique ionograms received near Scranton, PA transmitted by the Relocatable Over-the-Horizon Radar (ROTHR) in Chesapeake, Virginia. These observations are collected with the GNU Chirpsounder2 software, an open source software package capable of creating ionograms from frequency modulated (FM) chirp ionosondes. This ionospheric sounding mode will be implemented in the currently under-development Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), a ground-based multi-instrument system designed to remote-sense the ionosphere using signals of opportunity. Using the data from the oblique ionograms, we generate the Range Time Intensity (RTI) plots that show ionospheric dynamics through measured path length variations as a function of time. We also compare the RTI plots with Range-Time-Parameter (RTP) plots from the SuperDARN HF  radar in Blackstone, Virginia which commonly observes direct backscatter from decameter-scale irregularities within the region of ionosphere traversed by the ROTHR signal. We also investigate the dependence of the occurrence of the mid-latitude irregularities on the level of the geomagnetic activity.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - An Overview of Oblique Soundings from Chirp Ionosondes T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Simal Sami A1 - Nathaniel A. Frissell A1 - Mary Lou West A1 - Dev Raj Joshi A1 - Juha Vierinen AB -

An ionospheric sounder, typically known as an ionosonde, is a radar device which is used to make observations of the ionized layer of the Earth’s upper atmosphere known as the ionosphere. The ionosonde works by transmitting high frequency (HF, 3-30 MHz) radio waves and observing the time delay of the ionospheric echoes. Ionosondes play an especially crucial role in our understanding both ionospheric dynamics and how radio wave propagation is impacted by the ionosphere. The data from an ionosonde is displayed in a type of plot known as an ionogram. A chirp ionosonde is a type of ionospheric sounder that produces ionograms by transmitting an HF signal that changes linearly in frequency with time. Conventional chirp ionosondes are used in a vertical sounding mode, in which signals are transmitted directly up to the ionosphere. This allows for measurements of electron density as a function of height for the bottomside ionosphere. Chirp ionosondes may also be used in an oblique sounding configuration, in which the transmitter and receiver are separated by a significant geographic distance. While the measurements of an oblique sounder are more complicated to interpret than a vertical sounder, a single transmitter can be used simultaneously by receivers in many different locations, thus allowing for a cost-effective increase in the number of ionospheric sampling points. The HamSCI Personal Space Weather Station plans to take advantage of this fact by using signals-of-opportunity from the global network of pre-existing chirp ionosonde transmitters. In this presentation, we give a brief overview of chirp ionosondes and their uses in studying ionospheric dynamics.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - CONF T1 - HamSCI Personal Space Weather: Architecture and Applications to Radio Astronomy T2 - Annual (Summer) Eastern Conference Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Typinski A1 - William D. Engelke A1 - David R. Larsen A1 - David G. McGaw A1 - Hyomin Kim A1 - David M. Witten, II A1 - Julius M. Madey A1 - Kristina V. Collins A1 - John C. Gibbons A1 - David Kazdan A1 - Aidan Montare A1 - Dev Raj Joshi A1 - Veronica I. Romanek A1 - Cuong D. Nguyen A1 - Stephen A. Cerwin A1 - William Liles A1 - Jonathan D. Rizzo A1 - Ethan S. Miller A1 - Juha Vierinen A1 - Philip J. Erickson A1 - Mary Lou West AB -

The Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is a citizen science initiative to develop a new modular set of ground-based instrumentation for the purpose of studying the structure and dynamics of the terrestrial ionosphere, as well as the larger, coupled geospace system. PSWS system instrumentation includes radio receivers sensitive to frequencies ranging from the very low frequency (VLF) through very high frequency (VHF) bands, a Global Navigation Satellite System (GNSS) receiver to provide Total Electron Content (TEC) measurements and serve as a precision time and frequency reference, and a ground magnetometer sensitive to ionospheric and geospace currents. Although the PSWS is designed primarily for space weather and space science, its modular and open design in both hardware and software allows for a variety of use cases. The core radio instrument of the PSWS, the TangerineSDR, is a wideband, direct sampling 100~kHz to 60~MHz field programmable gate array (FPGA)-based software defined radio (SDR) receiver with direct applicability to radio astronomy. In this paper, we describe the PSWS and TangerineSDR architecture, show examples of how the TangerineSDR could be used to observe Jovian decametric emission, and discuss the applicability of the TangerineSDR to radio astronomy in general.

JF - Annual (Summer) Eastern Conference PB - Society of Amateur Radio Astronomers (SARA) CY - Virtual UR - https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference ER - TY - CONF T1 - HamSCI Personal Space Weather Station (PSWS): Architecture and Current Status T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Dev Joshi A1 - Veronica I. Romanek A1 - Kristina V. Collins A1 - Aidan Montare A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Travis Atkison A1 - Hyomin Kim A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Witten A1 - Julius Madey A1 - H. Ward Silver A1 - William Liles A1 - Steven Cerwin A1 - Philip J. Erickson A1 - Ethan S. Miller A1 - Juha Vierinen AB -

Recent advances in geospace remote sensing have shown that large-scale distributed networks of ground-based sensors pay large dividends by providing a big picture view of phenomena that were previously observed only by point-measurements. While existing instrument networks provide excellent insight into ionospheric and space science, the system remains undersampled and more observations are needed to advance understanding. In an effort to generate these additional measurements, the Ham Radio Science Citizen Investigation (HamSCI, hamsci.org) is working with the Tucson Amateur Packet Radio Corporation (TAPR, tapr.org), an engineering organization comprised of volunteer amateur radio operators and engineers, to develop a network of Personal Space Weather Stations (PSWS). These instruments that will provide scientific-grade observations of signals-of-opportunity across the HF bands from volunteer citizen observers as part of the NSF Distributed Array of Small Instruments (DASI) program. A performance-driven PSWS design (~US$500) will be a modular, multi-instrument device that will consist of a dual-channel phase-locked 0.1-60 MHz software defined radio (SDR) receiver, a ground magnetometer with (~10 nT resolution and 1-sec cadence), and GPS/GNSS receiver to provide precision time stamping and serve as a GPS disciplined oscillator (GPSDO) to provide stability to the SDR receiver. A low-cost PSWS (< US$100) that measures Doppler shift of HF signals received from standards stations such as WWV (US) and CHU (Canada) and includes a magnetometer is also being developed. HF sounding algorithms making use of signals of opportunity will be developed for the SDR-based PSWS. All measurements will be collected into a central database for coordinated analysis and made available for public access.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - Generic T1 - Mid-latitude Irregularities in the Early Results from the Ionospheric Sounding Mode Using Chirp Ionosondes of Opportunity for the HamSCI Personal Space Weather Station T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Dev Joshi A1 - Nathaniel A. Frissell A1 - William Liles A1 - Juha Vierinen A1 - Ethan S. Miller AB -

The objective of the Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is to develop a distributed array of ground-based multi-instrument nodes capable of remote sensing the geospace system. This system is being designed with the intention of distribution to a large number of amateur radio and citizen science observers. This will create an unprecedented opportunity to probe the ionosphere at finer resolution in both time and space as all measurements will be collected into a central database for coordinated analysis. Individual nodes are being designed to service the needs of the professional space science researcher while being cost-accessible and of interest to amateur radio operators and citizen scientists. At the heart of the HamSCI PSWS will be a high performance 1 – 50 MHz software defined radio (SDR) with GNSS-based precision timestamping and frequency reference. This SDR is known as the TangerineSDR and is being developed by the Tucson Amateur Packet Radio (TAPR) amateur radio organization. The primary objective of PSWS system is to gather observations to understand the short term and small spatial scale ionospheric variabilities in the ionosphere-thermosphere system. These variabilities are important for understanding a variety of geophysical phenomena such as Traveling Ionospheric Disturbances (TIDs), Ionospheric absorption events, geomagnetic storms and substorms. We present early results suggesting signatures of Traveling Ionospheric Disturbances (TIDs) from an ionospheric sounding mode that we intend to implement on the PSWS system, currently implemented on an Ettus N200 Universal Software Radio Peripheral (USRP) using the open source GNU Chirpsounder data collection and analysis code.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - CONF T1 - Observations of Mid-latitude Irregularities Using the Oblique Ionosonde Sounding Mode for the HamSCI Personal Space Weather Station T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Dev Joshi A1 - Nathaniel A. Frissell A1 - William Liles A1 - Juha Vierinen AB -

The spread in the echoes of high-frequency (HF, 3-30 MHz) radio waves from the F-region of the ionosphere has been the earliest indication of plasma density irregularities in the mid-latitude F region ionosphere. Although mid-latitude spread F has been widely studied, the plasma instability mechanisms for these irregularities are still largely unknown. This phenomenon can cause radio wave scintillation effects that degrade the performance of man-made technologies such as satellite communications and global navigation satellite systems (GNSS). Understanding these irregularities so that they can be anticipated and mitigated are important aspects of space weather research. The occurrence climatology and variability can also be helpful in modeling efforts of these irregularities. Here, we present signatures of mid-latitude irregularities observed in oblique ionograms received near Scranton, PA transmitted by the Relocatable Over-the-Horizon Radar (ROTHR) in Chesapeake, Virginia. These observations are collected with the GNU Chirpsounder2 software, an open-source software package capable of creating ionograms from frequency modulated (FM) chirp ionosondes. This ionospheric sounding mode will be implemented in the currently under development Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), a ground-based multi-instrument system designed to remote-sense the ionosphere using signals of opportunity.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - CONF T1 - Sounding the Ionosphere with Signals of Opportunity in the High-Frequency (HF) Band T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - Ethan S. Miller A1 - Gary S. Bust A1 - Gareth W. Perry A1 - Stephen R. Kaeppler A1 - Juha Vierinen A1 - Nathaniel A. Frissell A1 - A. A. Knuth A1 - Philip J. Erickson A1 - Romina Nikoukar A1 - Alexander T. Chartier A1 - P. Santos A1 - C. Brum A1 - J. T. Fentzke A1 - T. R. Hanley A1 - Andrew J. Gerrard AB -

The explosion of commercial off-the-shelf (COTS) education- and consumer-grade hardware supporting software-defined radio (SDR) over the past two decades has revolutionized many aspects of radio science, bringing the cost and calibration of traditionally complex receiver hardware within the grasp of even advanced amateur experimenters. Transmission has now become the limiter of access in many cases, particularly through spectrum management and licensing considerations. Fortunately, several classes of signals endemic to the HF band lend themselves to processing for ionospheric characteristics: time and frequency standard broadcasters, surface-wave oceanographic radars, amateur radio transmissions, and ionospheric sounders.

This presentation is a tour of these signals of opportunity and techniques for collecting and processing them into ionospheric characteristics, with emphasis on distributed receivers collecting on a small number (four or fewer) of coherent channels. Receiving techniques will be discussed for near-vertical (“quasi-vertical”) incidence skywave (NVIS or QVI), long-distance oblique soundings, and transionospheric sounding. Soundings will be demonstrated from space-based, ground-based, and maritime platforms.

Binary, Doppler, delay, cone angle of arrival, and polarization observations will be exploited, depending on the signal type and capability of the collector. Each of these techniques conveys different, but not always “orthogonal,” information about the ionospheric skywave channel. The information content of each datum will be discussed with respect to the implications for inverting the local or regional ionosphere from the observations. More importantly than inverting the full ionosphere, some of these techniques are sensitive indicators of ionospheric irregularities, structures, and instabilities, that might otherwise be difficult to study due to limited geographic coverage with larger, more exquisite instrumentation.

JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER -