Page 331 - Fundamentals of Radar Signal Processing
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FIGURE 5.3 Notional Doppler spectrum of ground clutter observed from a
moving radar platform: (a) sources of clutter return, (b) notional clutter
spectrum in the boresight range bin, (c) notional spectrum in the altitude line
range bin.
As shown in Fig. 5.3a, the mainlobe clutter (MLC) will occur at some
positive Doppler shift and the appropriate range bins. Clutter echo received
from below the aircraft will occur at a near range bin corresponding to the
aircraft altitude and at zero Doppler shift. This clutter component is termed the
altitude line (AL). Although it is transmitted and received through the radar
sidelobes, the altitude line nonetheless tends to be relatively strong due to the
relatively short vertical range and the high reflectivity of most clutter at normal
