Beam and Filter Straddle Losses in an ESA Search Radar
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The present study was undertaken to quantify several types of losses encountered when using an electronically-scanned array ESA. The losses examined include beam straddle losses, eclipsing losses, and range-Doppler straddling losses. The losses were studied for volume search radars with square and hexagonal search patterns as well as horizon search radar. The radar search equations for an ESA radar for both volume and horizon search are first derived. The beam straddle loss is then found, including the effect of range eclipsing for a high pulse repetition frequency PRF radar. The hexagonal search pattern has about 0.5 to 1 dB less loss than the square search. This loss is a strong function of probability of detection and duty factor precluding the insertion of a constant loss term in the radar range equation for these effects. A derivation of range and Doppler straddling losses follows, showing that they vary only slightly with the probability of detection and thus can be represented by a constant depending only on range-gate and Doppler-filter spacings. All losses were found to be very insensitive to the probability of false alarm in the range of 10-4 to 10-8, with the higher false-alarm rates giving slightly lower losses. The summary gives an example of a radar design to illustrate the use of the present results.
- Active and Passive Radar Detection and Equipment