Extended Abstract (2.7M)12.4
Data Quality Control for the SZ(8/64) Phase Code for the Mitigation of Range and Velocity Ambiguities in the WSR-88D
Gregory Meymaris, NCAR, Boulder, CO; and S. Ellis, J. Hubbert, and M. Dixon
A significant problem in retrieving Doppler velocities for the WSR-88D is range folding. This is caused by the fact that the unambiguous range increases with increasing pulse repetition time (PRT), while the unambiguous, or Nyquist, velocity decreases with increasing PRT. Therefore, adjusting the PRT to obtain a desirable unambiguous Nyquist interval, results in a small unambiguous range and thus inadequate area coverage. Conversely, a PRT that provides a large unambiguous range delivers unacceptably small Nyquist intervals, and thus severe velocity folding. One solution is to phase shift the transmitted pulses using a predetermined pattern called the SZ(8/64) phase code. The spectral moments from the multiple trip echoes can then be obtained by various recovery procedures. This approach has been shown to be a promising technique through simulation experiments and field studies on NCAR's S-Pol radar and NSSL's KOUN testbed radar. An important piece of any algorithm that generates spectral moments (Z,V, and W) is data quality. All spectral moment algorithms will fail, or have unacceptably high errors, in certain regimes, e.g. low signal to noise ratio. Moments that have questionable quality need to be censored so that downstream processing is performed only on good data. In this paper, the methods and performance of some censoring techniques that make use of, if available, spectral moments from long PRT (surveillance) scans, spectral moments from the decoded short PRT (Doppler) scan, and spectral shape of the decoded weak trip spectra, will be discussed as well as clutter filtering while using SZ(8/64).
Session 12, Radar IIPS and Applications Part II (ROOM 613/614)
Wednesday, 14 January 2004, 1:30 PM-5:30 PM, Room 613/614
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