Sporadic-E Observations during LoVHF Transionospheric Direction Finder Measurements
Abstract
A year long experimental program was conducted to measure refractive bending or how much the signal deviates from true line of sight, at low VHF (LoVHF) frequencies (29.5 MHz), and to determine whether this deviation or error could be predicted using large-scale ionospheric models such as the Ionospheric Conductivity and Electron Density (ICED) program. An experiment to directly measure the angle of arrival of a 29.5 MHz signal from an orbiting satellite was successfully completed. The satellite was in a circular orbit at an altitude of 1000 km. It was shown that refractive errors can be directly related to the electron density along the measurement slant range. The introduction of irregular patches of electron density occurring during sporadic-E events produced both horizontal and vertical gradients introducing large errors in both azimuth and elevation measurements. Nineteen test periods in May, June, July, and August 1989 were affected by mid-latitude sporadic-E with the daytime E- region critical frequencies (foEs) reaching 13 MHz in one case. This paper will present examples of these effects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA270619
Entities
People
- Robert B. Rose
Organizations
- Naval Command, Control and Ocean Surveillance Center