Page 393 - Fundamentals of Radar Signal Processing

FIGURE 5.26 Blind zones in Doppler and range: (a) blind zones in Doppler due
to the periodic repetition of the mainlobe clutter spectrum, (b) blind zones in
range due to pulse transmission and near-in clutter in a monostatic radar. Partial
eclipsing of two of the three target echoes is also shown.

Recall that there are also blind zones in range or fast time in a monostatic
radar as discussed in Sec. 3.1.3. The range blind zones due to pulse eclipsing

are deliberately extended in some systems by keeping the receiver disconnected
from the antenna for an additional period of time beyond the pulse length. The
purpose is to avoid saturating the receiver with very strong near-in clutter
returns, such as those from the altitude line. Figure 5.26b illustrates range blind
zones and eclipsing. Pulses of duration τ are transmitted every T seconds as
shown in the upper line. The middle line shows three target echoes after each

pulse and strong near-in clutter returns. The bottom line shows that the receiver
will be off during the time of transmission of the pulse and of reception of the