Study of Ionospheric Irregularities for the Assessment of Impacts on Communication/Navigation System
Abstract
Radiowave scintillation caused by ionospheric density irregularities will degrade the space communication/navigation quality. The goal of the proposed project is to study the irregularity characteristics and global occurrence distributions (solar maximum vs. solar minimum) so as to assess the impacts on communication, navigation and positioning system. The first part of the project is to study the scintillation events observed by the AFRL-NCU SCINDA Pingtung Station. The scintillation data will routinely give us the background ionospheric day and night drift velocities in the Taiwan sector. Any coincident observations with the FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2 GPS occultation experiment (GOX) will help us understand the radiowave propagation characteristics from ionospheric irregularities in the UHF and L1 bands. The scintillation data will be analyzed by the Hilbert-Huang transform (HHT) method to decompose the time-series data into many intrinsic mode functions (IMFs) each contains a distinctive oscillation frequency (characteristic scale length) that can be inferred back to the irregularity structure that causes the dominant scintillation. The time-frequency spectragram obtained by the HHT analysis can reveal how irregularity structure changes with time. The second part of the project is to study the sun-synchronous orbiting FORMOSAT-5 in-situ measured ionospheric ion density, ion vector velocity, ion and electron temperature, and ion composition for the irregularity characteristics and global occurrence distribution. The unprecedented 8192 Hz sampled ion density data will resolve the irregularity structure down to ~2 m scale length for a better understanding of L band scintillation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 09, 2018
- Source ID
- FA23861810115
Entities
People
- Lung-chih Tsai
Organizations
- Air Force Office of Scientific Research
- National Central University
- United States Air Force