Accession Number : ADP006316

Title :   Measurements of Trans-Ionospheric Effects Using Signals from GPS,

Corporate Author : GEOPHYSICS LAB (AFSC) HANSCOM AFB MA

Personal Author(s) : Bishop, G. J. ; Klobuchar, J. A. ; Basu, Santimay ; Clynch, J. R. ; Coco, D. S.

Report Date : 03 MAY 1990

Pagination or Media Count : 11

Abstract : Effects of the ionosphere can be significant to modern RF systems which depend on trans-ionospheric signal propagation. Delay effects caused by ionospheric total electron content, (TEC), and scintillation effects due to small-scale ionospheric irregularities, are of particular importance since they can, for example, cause ranging errors and signal or target fades. Signals from the Global Positioning System (GPS) satellites will provide the opportunity to measure TEC and scintillation parameters on a continuous basis in several directions from anywhere on earth. GPS signals have been used since 1984 to make measurements of polar cap TEC and L-Band scintillation, at Thule, Greenland. Concurrent observations of amplitude fading at 250 MHz link these GPS measurements to a large data base of polar scintillation at that frequency. Examples of these data will be given which illustrate the extreme variability of the polar cap ionosphere, which can be a significant limitation to trans-ionospheric systems which must operate in this part of the world. This paper will also review ionospheric measurement capability of GPS receivers using the full GPS P-code capability, contrasted with newer, less costly, instruments which make much more limited measurements without requiring knowledge of the GPS P-codes.

Descriptors :   *IONOSPHERIC PROPAGATION, *ELECTRON DENSITY, IONOSPHERIC SCINTILLATION, GLOBAL POSITIONING SYSTEM, RADIO LINKS, L BAND, POLAR REGIONS, FADING(ELECTROMAGNETIC WAVES).

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE