Ground Clutter Filters for Staggered Pulse Trains

摘要

Several methods for canceling ground clutter on Doppler weather radars that operate with staggered pulse repetition times (PRTs) are investigated. The scheme is developed that consists of two filters that operate sequentially, so that the overall filter is time-varying, with periodically changing coefficients. This filter is analyzed theoretically and through simulations for a stagger ratio of 3/2, which extends the unambiguous velocity interval (at a wavelength of 5 cm) to 50 m/s. The amplitude characteristic of the filter over this interval is very good, but the phase characteristics, which is nonlinear in about 40 percent of the interval, requires that a special decision logic be used for velocity estimation. At high signal-to-noise ratio (greater than 20 dB), mean velocities obtained from the output meet terminal Doppler weather radar specifications. Keywords: Pulse repetition time; Next generation weather radar; Weather; Doppler; Radar; Ground clutter; NEXRAD. (jhd)