Demonstration of Super-resolution Measurements with Phased Array Radar
Time series data were collected at azimuthal spacing of half a beamwidth apart in a sector that covers 90o to test this concept. The data from three adjacent radials are combined to obtain the spectral moments. Because the pulse repetition time (PRT) was 800 μs and the number of pulses per radial was 40, it is possible to mimic a typical WSR-88D Doppler scan. Using every fourth sample, a surveillance scan (for reflectivity at the lowest elevation) of the super-resolution mode was emulated. Examined are weighted averages of moment estimates from adjacent radials as well as joint signal processing from these radials. The dwell time per radial of processed data is chosen to match the current super-resolution mode on the WSR-88D. Furthermore, a slightly modified CLEAN-AP ground clutter filter (Torres and Warde 2014) is applied and evaluated with the data. A data set from a supercell tornadic storm is also examined. A radial of this data consist of two batches of pulses; one batch has 12 samples at a PRT of 3.0 ms and the other has 25 samples at a PRT of 0.8 ms. A combination of time series as well as a combination of second order moments from adjacent radials is used to estimate the reflectivity and mean Doppler velocity. It is demonstrated that acceptable ground clutter canceling can be achieved on data from either of the two PRTs. Comparisons of results obtained with various window functions and total dwell times are made.
References: Torres, S., and D. Warde, 2014: Ground clutter mitigation for weather redar using the autocorrelation spectral density. J. Atmos. Oceanic Technol., in press. Zhang, G., D.Zrnic, L. Borowska, and Y. Al-Rashid, 2015: Hybrid Scan and Joint Signal Processing for a High Efficiency MPAR. 31st Conference on Environmental Information Processing Technologies, American Meteorological Society Annual Meeting, 2015, Phoenix, Az.