THE SPECTRAL CHARACTERISTICS AND TEMPORAL BEHAVIOR OF HF RADAR ECHOES FROM OVER-THE-HORIZON AIRCRAFT TARGETS
NAVAL RESEARCH LAB WASHINGTON DC
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This report summarizes the results of three years of over-the-horizon OTH radar tracking studies. The purpose of these studies was to investigate the feasibility and reliability of utilizing ionospheric propagation paths as a means of extending radar usefulness to ranges beyond the geometric horizon. The principal instrument used in these studies was the Madre research radar, which is a high-power, coherent, moving-target-indicating MTI radar operating in the high-frequency portion of the radio spectrum. Detailed analyses of the following three phases of the OTH aircraft target study were made a aircraft time-range tracking, b temporal behavior of the aircraft target echo, and c spectral characteristics of the aircraft target echo. The essential results are, respectively a a range measurement accuracy of approximately 5 percent may be expected under usual conditions, even if no effort is made to correct the raw slant-range data for the effects of ionospheric path b a typical OTH target can normally be acquired 60 percent of the time during which it is illuminated, compared to a 6 percent acquisition rate for noncoherent radars and c the number of aircraft in a closely spaced group of aircraft can be determined and separated in velocity with a doppler resolution of at least 110 cps.
- Active and Passive Radar Detection and Equipment