Accession Number:

ADA034024

Title:

DAASM Project - High Latitude Aircraft HF Propagation Experiment. Part II,

Descriptive Note:

Corporate Author:

ROME AIR DEVELOPMENT CENTER GRIFFISS AFB N Y

Personal Author(s):

Report Date:

1976-07-01

Pagination or Media Count:

25.0

Abstract:

The purpose of the DAASM project was to investigate the effects of the auroral ionosphere on long-range propagation of HF radio signals. The HF radio signals transmitted from an aircraft and received at Goose Bay, Labrador, were analyzed to determine the degree to which the Doppler frequency and arrival angle were perturbed by passage through the auroral ionosphere. As part of this analysis the propagation modes for each data sample were determined, using vertical and oblique incidence sounders. The experiment detail and the data, analyzed in this report in more detail, were described in a prior DAASM report AFCRL-TR-75-0290ERP No. 516. E-mode propagation dominated the data samples and may be considered good propagation conditions. The median value for the absolute angular deviation was 2 deg from the true bearing of the aircraft, well within the uncertainity of the aircraft position. The maximum deviation was 9 deg. The median value for the angular spreading was 4 deg and it varied between 2 and 6 deg. F-mode signals showed a median angular spreading of 5 deg. Finally, the Doppler frequency spread varied between 0.3 and 0.8 Hz with a median of 0.33 Hz. In general, the auroral effects on E-mode propagation were small, though considerably larger than would be expected at midlatitude. Author

Subject Categories:

  • Atmospheric Physics
  • Active and Passive Radar Detection and Equipment
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE