11/18/02Technical Interchange Meeting Progress in FY-02 Research RDA –Capability to collect time series data –Control of phase shifter Phase coding –Sigmet’s implementation of SZ algorithm –Ground clutter filtering if P 1 < P 2 –Collected sample time series of SZ coded data

11/18/02Technical Interchange Meeting Research RDA Status Operational in legacy and RRDA mode Both modes accommodate RVP-7 in parallel RVP-7 used for JPOL demo Plan to integrate RVP-8 ASAP

11/18/02Technical Interchange Meeting RRDA Status Full control of radar Integrated with ORPG Phase shifter control Versatile VCP structures and tools Real-time displays VCP 43 & 44 implemented, data to ROC Real-time phase coded acquisition with first trip decoding

11/18/02Technical Interchange Meeting RRDA Status Staggered PRT capability implemented Working on real-time software for staggered PRT Continuous archive level 1 and 2 for several hours Real-time playback of archive data Data storage in compressed native format Matlab format and ingest into Matlab Recording on tape, CD, and/or DVD

11/18/02Technical Interchange Meeting SZ Decoding Algorithms Analysis of Sigmet’s SZ decoding algorithm –Sigmet provided internal notes on decoding algorithm Comparison with NSSL’s SZ-1 decoding algorithm –Major difference is in the substitution method MATLAB simulations to compare performance

11/18/02Technical Interchange Meeting Sigmet’s Implementation

11/18/02Technical Interchange Meeting SZ-1 algorithm

11/18/02Technical Interchange Meeting SD(v) for the two methods

11/18/02Technical Interchange Meeting SD(σ v ) for the two methods

11/18/02Technical Interchange Meeting Bias in σ v for the two methods

11/18/02Technical Interchange Meeting Comparison of Random Phase and SZ code – Lincoln Labs

11/18/02Technical Interchange Meeting GCF and Phase Coding Optimum ground clutter filter –Frequency response –Notch width Ground clutter filtering if P 2 > P 1 –Sigmet reverts to random phase processing –SZ algorithm was modified to address this problem

11/18/02Technical Interchange Meeting Optimum Clutter Filter S(v) + N C(v) + N Noise level: N N1N1 v v C(v) + N 1 GCF(v) Input Output Normalized noise level: 1 v S(v) + N N

11/18/02Technical Interchange Meeting Effects of the number of samples

11/18/02Technical Interchange Meeting Optimum filter width 1.3

11/18/02Technical Interchange Meeting Clutter filtering if P c >P 2 >P 1 1.Re-cohere 1 st trip and filter ground clutter 2.Restore lost spectral coefficients of 2 nd trip replicas 3.Re-cohere 2 nd trip, obtain moments, and filter 2 nd trip signal 4.Re-cohere 1 st trip and obtain moments

11/18/02Technical Interchange Meeting Restoration of lost 2 nd trip spectrum replica 1.Use the remaining replicas to determine the magnitude and phase –similar to substitution and works at narrow widths 2.Reconstruction of magnitudes and phases in case there is only one overlap of the spectral replicas –extends the range of spectrum widths –requires solution of linear equations (overdetermined system)

11/18/02Technical Interchange Meeting GCF effect on 2 nd trip spectrum replicas

11/18/02Technical Interchange Meeting P 2 /P 1 Ratio for which spectral moments of 1 st trip can be recovered

11/18/02Technical Interchange Meeting Data Collection Volume Coverage Pattern Definitions –ROC requested non-standard VCPs –Modified RRDA VCP definitions to accommodate new requirements Automatic switch between phase-coded and non-phase- coded elevation cuts Staggered PRT Level-1 Data Archiving –Expanded data headers to include new metadata –Currently support MATLAB and RRDA internal formats

11/18/02Technical Interchange Meeting Collection of SZ coded data Reflectivity field PRT #1 T = 3.1 ms r a = 466 km v NYQ = 8.92 m s -1

11/18/02Technical Interchange Meeting Collection of SZ coded data Doppler velocity field PRT #1 T = 3.1 ms r a = 466 km v NYQ = 9 m s -1

11/18/02Technical Interchange Meeting Real-time decoding of 1 st trip PRT #4 (T = 1.17 ms) r a = 175 km v NYQ = 24 m s -1 PRT #8 (T = 0.78 ms) r a = 117 km v NYQ = 35 m s -1

11/18/02Technical Interchange Meeting Plans Real-time implementation of SZ algorithm Real-time implementation of Staggered PRT SPS Simulator Oversampling and Whitening in range

11/18/02Technical Interchange Meeting SPS Simulator R/V algorithms require development at the RDA DSP level –Rapid algorithm prototyping and validation –Data visualization tools –Off-line development using Archive 1 data Working on simulation of RRDA DSP (Legacy WSR-88D HSP/PSP) using MATLAB –Capability to simulate RVP-8

11/18/02Technical Interchange Meeting Plans for the SPS Simulator Data Analysis –Spectral analysis Data Processing –R/V ambiguitiy mitigation Phase coding Staggered PRT –Interaction with other techniques Oversampling and whitening in range

11/18/02Technical Interchange Meeting Oversampling of Weather Echoes in Range L samples within the pulse

11/18/02Technical Interchange Meeting Whitening-Transformation-Based Estimates Oversample in range by a factor of L –Range samples are correlated –Correlation is known assuming uniform reflectivity Decorrelate oversampled range data –Whitening transformation is derived from “known” C –Works for SNR > 15 dB Compute autocovariances for each range gate Average autocovariances from L range gates –Statistical errors are reduced

11/18/02Technical Interchange Meeting Reduction in statistical errors by processing oversampled signals in range PRT = 3 ms M = 32 L = 9 NEXRAD specification

11/18/02Technical Interchange Meeting Plans for Oversampling and Whitening in Range Collection of oversampled data with RRDA –Long pulse, L = 3 –Digital receiver, L ≥ 5 –Examine RVP-8 capabilities Statistical analysis –Matched filter, Regular averaging, Whitening Visual comparison of PPI displays Effects of reflectivity gradients Pseudo-whitening techniques