Accession Number:

ADA048116

Title:

Adaptive Mapping of Mid-Latitude Ionosphere.

Descriptive Note:

Air Force surveys in geophysics,

Corporate Author:

AIR FORCE GEOPHYSICS LAB HANSCOM AFB MASS

Report Date:

1977-08-03

Pagination or Media Count:

20.0

Abstract:

Maps of the monthly median of refractive effects are used by precision navigation and radar systems to correct for measurement errors caused by the ionosphere. Calculated off line using available climatologies of the pertinent ionospheric parameters, they are used in real time systems to remove 70 to 75 percent of the monthly rms error. When greater precision is required, these maps may be adapted by any of several local measurements of current ionospheric conditions. The residual refractive error is dependent on the density of these local measurements in space and time and on their ability to characterize the current ionosphere. Systematic variations of the ionosphere are usefully predicted over a few hours. Local features that have large geophysical scale size, such as the nighttime trough and the plasmapause enhancement of the mid-latitude ionosphere, are tracked by sequential measurements and may be mapped in space and local time across the entire system field of view during quiet geophysical periods. During disturbed periods, however, their dynamic behavior may require more frequent specifications and, in addition, very large features can develop which are sharply confined to small areas of the coverage region.

Subject Categories:

  • Atmospheric Physics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE