Accession Number : ADP006378

Title :   ALTAIR UHF Observations of Backscatter Enhancement,

Corporate Author : MISSION RESEARCH CORP MONTEREY CA

Personal Author(s) : Knepp, Dennis L.

Report Date : SEP 1991

Pagination or Media Count : 7

Abstract : During the Defense Nuclear Agency (DNA) PEAK (Propagation Effects Assessment - Kwajalein) experiment in August 1988, the ALTAIR VHF/UHF wide bandwidth radar was used to track spherical satellites in low-earth orbit. The purpose of the experiment was to obtain radar data during the most severe propagation disturbances available naturally. The PEAK experiment has been quite successful, giving many measurements of strong scintillation as well as the first measurements of frequency-selective fading on propagating radar pulses. In this paper the experimental results are used to demonstrate an enhancement, due to scattering, in the average received power that is observed during severe scintillation. The observed statistics of the enhancement are compared to analytic calculations using the Nakagami-m distribution with very good agreement. This enhancement is predictable on the basis of the first-order amplitude statistics for two-way radar propagation in a monostatic propagation geometry as well as by a more thorough analysis using reciprocity; both analytic approaches are presented here. The enhancement is important for both ground and space-based radars that have to operate during scintillation, since as much as a 3 decibel increase in the target (and clutter) signal-to-noise ratio is possible, depending on the severity of the scintillation and on the radar transmit/receive geometry.

Descriptors :   *RADAR SIGNALS, *RADAR TRACKING, *ATMOSPHERIC SCATTERING, AGREEMENTS, AMPLITUDE, AUGMENTATION, BANDWIDTH, DISTRIBUTION, EARTH ORBITS, FREQUENCY, GEOMETRY, NOISE, ORBITS, POWER, PROPAGATION, PULSES, RADAR, RADAR PULSES, RATIOS, SCATTERING, SCINTILLATION, SIGNAL TO NOISE RATIO, SIGNALS, SPACE BASED, STATISTICS, BACKSCATTERING, IONIZATION, ANGLE OF ARRIVAL, RADAR ANTENNAS, RADAR CROSS SECTIONS, SCIENTIFIC SATELLITES, TARGET DETECTION, MILITARY EQUIPMENT, DATA ACQUISITION.

Subject Categories : Active & Passive Radar Detection & Equipment
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE