Page 398 - Fundamentals of Radar Signal Processing

FIGURE 5.30 “3 of 8” blind zone map obtained using evolutionary algorithms
to select the PRIs. See text for details.

5.4 Pulse Pair Processing

Pulse pair processing (PPP) is a form of Doppler processing common in
meteorological radar. Unlike the MTI and pulse Doppler techniques discussed
so far in this chapter, the goal of pulse pair processing is not clutter suppression
to enable the detection of moving targets. In PPP it is assumed that the spectrum
of the slow-time data consists of noise and a single Doppler peak, generally not

located at zero Doppler (though it could be), that is due to echo from moving
weather events such as wind-blown rain or other particulates. The goal of PPP
is to estimate the parameters of that spectral peak. These are then used as the
input to higher-level algorithms for estimating precipitation types and rates,
forecasting severe weather, and so forth in both ground-based and airborne
weather radars. In airborne radars, it is also one of the techniques used for
windshear detection.

Pulse pair processing assumes the radar is looking generally upward if it is
ground-based, or forward if it is airborne. Consequently, it is assumed that
ground clutter competing with the weather signatures is small or negligible, or
has been removed by MTI filtering. The notional Doppler spectrum S (F)
y
assumed by PPP is shown in Fig. 5.31. It consists only of white noise and a

single spectral peak due to backscatter from weather-related phenomena