Extended Abstract (136K)P4D.2
Phase Coding for Polarimetric Radar
J.C. Hubbert, NCAR, Boulder, CO; and V. Chandrasekar, R. J. Keeler, and N. Bharadwaj
The fundamental range and velocity measurement limitation of pulsed radar systems is expressed by the following equation
ra va=cL/8
where ra, va are the unambiguous range and velocity, respectively, for wavelength
L and where c is the speed of light.Since the product
rava is a constant for a particular wavelength,
increasing either one (ra or va) necessarily
decreases the other. For L=10 cm (S-band) and a typical pulse repetition time (PRT)
of 1ms, ra=150km and va=25m/s. Weather phenomena routinely
exceed both of these limits. Phase coding of the transmit pulses for single
polarization radars has been shown to be an effective method for the separation of
range overlaid echoes thus extending ra without compromising va.
To date phase coding has only been considered for single polarization radars.
The advent of new high speed PC based radar receivers, with the ability
of real time spectral processing, makes phase coding for dual
polarization radars feasible.
Issues surrounding phase coding for dual polarized radars are discussed and
phase coding schemes are suggested. It is shown that is possible for radars
with two transmitters
to retrieve unaliasd velocities for weather targets while simultaneously having
large unambiguous range.
Poster Session 4D, Signal Processing Poster
Sunday, 10 August 2003, 1:30 PM-3:30 PM
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