Page 408 - Fundamentals of Radar Signal Processing

coverage are 60 km and 300 m/s (±150 m/s), respectively. The range limit might

be set by the expected maximum detection range of the radar, while the velocity
limit might be set by the maximum expected relative velocity of targets of
interest. The shaded area indicates a range of PRFs (in this case, 2.5 to 20 kHz)
that will result in ambiguities in both dimensions. PRFs below 2.5 kHz will be
ambiguous in Doppler but not in range; those from 2.5 to 20 kHz will be
ambiguous in both; and those above 20 kHz will be ambiguous in range but not

in Doppler.

FIGURE 5.35 Low, medium, and high PRF regimes for a notional X-band radar.

The choice of PRF regime has major effects on the range-Doppler target
and clutter spectrum. Consider again the radar and clutter scenario associated
with Fig. 5.4 and suppose the maximum range and velocity intervals of interest
are 75 km and ±150 m/s. Now consider viewing the same scenario with low,
medium, and high PRFs of 2, 10, and 30 kHz, respectively. Table 5.3 lists the

unambiguous range, Doppler, and velocity intervals for each of these PRFs for
reference.