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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. Progress in FY-02. Operational in legacy and RRDA mode

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Progress in FY-02

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  1. Research RDA Capability to collect time series data Control of phase shifter Phase coding Sigmet’s implementation of SZ algorithm Ground clutter filtering if P1 < P2 Collected sample time series of SZ coded data Progress in FY-02 Technical Interchange Meeting

  2. 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 Research RDA Status Technical Interchange Meeting

  3. 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 RRDA Status Technical Interchange Meeting

  4. 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 RRDA Status Technical Interchange Meeting

  5. 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 Technical Interchange Meeting

  6. Sigmet’s Implementation Technical Interchange Meeting

  7. SZ-1 algorithm Technical Interchange Meeting

  8. SD(v) for the two methods Technical Interchange Meeting

  9. SD(σv) for the two methods Technical Interchange Meeting

  10. Bias in σv for the two methods Technical Interchange Meeting

  11. Comparison of Random Phase and SZ code – Lincoln Labs Technical Interchange Meeting

  12. GCF and Phase Coding • Optimum ground clutter filter • Frequency response • Notch width • Ground clutter filtering if P2 > P1 • Sigmet reverts to random phase processing • SZ algorithm was modified to address this problem Technical Interchange Meeting

  13. C(v) + N Input S(v) + N Noise level:N v GCF(v) N-1 1 C(v) + N v S(v) + N Output N Normalized noise level:1 v Optimum Clutter Filter Technical Interchange Meeting

  14. Effects of the number of samples Technical Interchange Meeting

  15. Optimum filter width 1.3 Technical Interchange Meeting

  16. Clutter filtering if Pc>P2>P1 • Re-cohere 1st trip and filter ground clutter • Restore lost spectral coefficients of 2nd trip replicas • Re-cohere 2nd trip, obtain moments, and filter 2nd trip signal • Re-cohere 1st trip and obtain moments Technical Interchange Meeting

  17. Restoration of lost 2nd trip spectrum replica • Use the remaining replicas to determine the magnitude and phase • similar to substitution and works at narrow widths • 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) Technical Interchange Meeting

  18. GCF effect on 2nd trip spectrum replicas Technical Interchange Meeting

  19. P2/P1 Ratio for which spectral moments of 1st trip can be recovered Technical Interchange Meeting

  20. 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 Technical Interchange Meeting

  21. Collection of SZ coded data Reflectivity field PRT #1 T = 3.1 ms ra = 466 km vNYQ = 8.92 m s-1 Technical Interchange Meeting

  22. Collection of SZ coded data Doppler velocity field PRT #1 T = 3.1 ms ra = 466 km vNYQ = 9 m s-1 Technical Interchange Meeting

  23. Real-time decoding of 1st trip PRT #4 (T = 1.17 ms) ra = 175 km vNYQ = 24 m s-1 PRT #8 (T = 0.78 ms) ra = 117 km vNYQ = 35 m s-1 Technical Interchange Meeting

  24. Plans • Real-time implementation of SZ algorithm • Real-time implementation of Staggered PRT • SPS Simulator • Oversampling and Whitening in range Technical Interchange Meeting

  25. 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 Technical Interchange Meeting

  26. 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 Technical Interchange Meeting

  27. Oversampling of Weather Echoes in Range L samples within the pulse Technical Interchange Meeting

  28. 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 Technical Interchange Meeting

  29. Reduction in statistical errors by processing oversampled signals in range PRT = 3 ms M = 32 L = 9 NEXRAD specification Technical Interchange Meeting

  30. 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 Technical Interchange Meeting

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