The Discovery of Novel Ionospheric Phenomenon Using a Software-Defined High Frequency Radar

Restricted (Penn State Only)
Author:
Bostan, Salih Mehmed
Graduate Program:
Electrical Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
June 15, 2018
Committee Members:
  • Julio Urbina, Dissertation Advisor
  • John D. Mathews, Committee Chair
  • James Kenneth Breakall, Committee Member
  • Sven G Bilen, Committee Member
  • David Bradley Spencer, Outside Member
  • Anthony J Ferraro, Special Member
Keywords:
  • ionosphere
  • ionospheric sounding
  • software-defined radar
  • artificial ionospheric modification
  • high frequency
Abstract:
After the discovery of the conducting layer in 1925, ionospheric sounders have been the most important tool to study the ionosphere. A dense network of ionosondes has been used to provide information on ionospheric conditions across the world, and HF radars have been used to obtain detailed information on ionospheric phenomena. However, there is still a significant lack of understanding of the time and spatial structure of the ionospheric plasma instabilities. Due to their high temporal resolution, some of the ionospheric events can be observed only with radar, which because of the relatively fewer radars in comparison to ionsondes, causes the events to be significantly under reported. Conventional radar systems are built with application-specific integrated circuits and dedicated hardware, both of which offer limited operational flexibility and are difficult to reconfigure. The new concept of software-defined-radar (SDR) brings versatility to radar systems because pulse generation, up-conversion, and down-conversion are implemented by means of software. In this dissertation, a novel design and implementation of a software-defined high frequency ionospheric radar, Penn State Ionospheric Radar Imager (PIRI), is described. Furthermore, preliminary results of unique ionospheric phenomenon detected by the system is presented. PIRI is designed to be a modest, low-cost, and low-power (600 W) radar system which is composed of commercial-off-the-shelf products and open-source software. It is designed to be mobile as it can easily be deployed at temporary locations to study local ionospheric disturbances. The software defined implementation of the radar allows the system to cover the entire HF band while reusing its core components. The PIRI HF radar system has been deployed in two locations. The first was used in Rock Springs, PA near Penn State, University Park campus. This location has been used for developing and testing. The other is in Arecibo, Puerto Rico near the Arecibo Observatory. It was deployed in March 2017 as a complementary instrument for an HF heating campaign. Observations from both locations under natural and artificially modified ionosphere include events such as sporadic-E, mid-latitude spread-F, and artificial spread-F. It is shown that a low-cost HF radar like PIRI can provide original and insightful results from both naturally and artificially occurring ionospheric disturbances with very high temporal resolution that an ionosonde cannot provide.