Design, Implementation, and Demonstration of a Staggered PRT Algorithm for the WSR-88D
01 Sep 2004-Journal of Atmospheric and Oceanic Technology (American Meteorological Society)-Vol. 21, Iss: 9, pp 1389-1399
TL;DR: The prototype algorithm incorporates a novel rule for the correct assignment of Doppler mean velocity that is needed to accommodate arbitrary stagger ratios that is integrated with the standard processing on the WSR-88D.
Abstract: This paper describes the implementation of the staggered pulse repetition time (PRT) technique on NOAA's research and development WSR-88D in Norman, Oklahoma. The prototype algorithm incorporates a novel rule for the correct assignment of Doppler mean velocity that is needed to accommodate arbitrary stagger ratios. Description of the rule, consideration of errors, and choice of appropriate stagger ratios are presented. The staggered PRT algorithm is integrated with the standard processing on the WSR-88D, some details of which are included in the paper. A simple ground clutter canceller removes the pure complex time series mean (DC) component from autocovariance estimates; censoring of overlaid echoes and thresholding are equivalent to those used on the WSR-88D. Further, a cursory verification of statistical errors indicates good agreement with theoretical expectations. Although the staggered PRT algorithm operates in real time, it was advantageous to collect several events of staggered PRT time s...
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TL;DR: To achieve the increase in computational power and data archiving needs required for high-temporal-resolution sampling, the signal processor was upgraded to a scalable, Linux-based cluster with a distributed computing architecture.
Abstract: Since 2007 the advancement of the National Weather Radar Testbed Phased-Array Radar (NWRT PAR) hardware and software capabilities has been supporting the implementation of high-temporal-resolution (∼1 min) sampling. To achieve the increase in computational power and data archiving needs required for high-temporal-resolution sampling, the signal processor was upgraded to a scalable, Linux-based cluster with a distributed computing architecture. The development of electronic adaptive scanning, which can reduce update times by focusing data collection on significant weather, became possible through functionality added to the radar control interface and real-time controller. Signal processing techniques were implemented to address data quality issues, such as artifact removal and range-and-velocity ambiguity mitigation, absent from the NWRT PAR at its installation. The hardware and software advancements described above have made possible the development of conventional and electronic scanning capabil...
83 citations
Cites background from "Design, Implementation, and Demonst..."
...The PRT controls the maximum unambiguous range and velocity, but different waveforms, such as staggered PRT, can be used to mitigate ambiguities (e.g., Torres et al. 2004)....
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...To mitigate range and velocity ambiguities (Doviak and Zrnić 2006), the signal processor can ingest multiple-pulserepetition-time (PRT) data such as ‘‘batch’’ or staggered PRT (Torres et al. 2004)....
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TL;DR: An improvement factor is introduced to quantify the BMX performance, which is defined by the reduction in data acquisition time using BMX when the same data accuracy obtained by a normal S-band phased-array radar is obtained.
Abstract: The recently installed S-band phased-array radar (PAR) at the National Weather Radar Testbed (NWRT) offers fast and flexible beam steering through electronic beam forming. This capability allows the implementation of a novel scanning strategy termed beam multiplexing (BMX), with the goal of providing fast updates of weather information with high statistical accuracy. For conventional weather radar the data acquisition time for a sector scan or a volume coverage pattern (VCP) can be reduced by increasing the antenna’s rotation rate to the extent that the pedestal allows. However, statistical errors of the spectral moment estimates will increase due to the fewer samples that are available for the estimation. BMX is developed to exploit the idea of collecting independent samples and maximizing the usage of radar resources. An improvement factor is introduced to quantify the BMX performance, which is defined by the reduction in data acquisition time using BMX when the same data accuracy obtained by a...
66 citations
TL;DR: In this paper, the authors show that the 3D wind fields retrieved in that framework can definitely be relied upon to achieve a consistent and detailed mapping of the airflow structure in various precipitation regimes despite radar baselines averaging −180 km and very limited scanning strategies.
Abstract: The recent deployment of an innovative triple pulse rise time (PRT) scheme within the French operational radar network allows for the simultaneous collection of reflectivity and radial velocity measurements up to a range of 250 km with no ambiguity. This achievement brings new perspectives in terms of operational exploitation of Doppler measurements including the capability to consistently perform multiple- Doppler wind synthesis in a fully operational framework. Using real and simulated Doppler observations, the authors show that the 3D wind fields retrieved in that framework can definitely be relied upon to achieve a consistent and detailed mapping of the airflow structure in various precipitation regimes despite radar baselines averaging _180 km and very limited scanning strategies. This achievement could be easily transposed to other operational networks and represents a remarkable opportunity to add further value to operational Doppler velocity measurements.
48 citations
Cites background from "Design, Implementation, and Demonst..."
...Thanks to the recent deployment of multiple pulse rise time (PRT) schemes in operational radar systems (Zrnic 1977; Torres et al. 2004; Tabary et al. 2005, 2006), it has become possible to mitigate the longlasting Doppler dilemma and to achieve extensive Doppler coverage while keeping velocity…...
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TL;DR: In this paper, a feature mask algorithm that objectively determines the presence of significant radar returns is described, which accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal free range gates.
Abstract: The scanning Atmospheric Radiation Measurement (ARM) Program cloud radars (SACRs) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20–30-km radius of the ARM fixed and mobile sites. Here, the postprocessing of the calibrated SACR measurements is discussed. First, a feature mask algorithm that objectively determines the presence of significant radar returns is described. The feature mask algorithm is based on the statistical properties of radar receiver noise. It accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal-free range gates. Using the nearest-in-time atmospheric sounding, the SACR radar reflectivities are corrected for gaseous attenuation (water vapor and oxygen) using a line-by-line absorption model. Despite having a high pulse repetition frequency, the SACR has a narrow Nyquist velocity limit and thus Doppler velocity folding is commonly observed. An unfolding algorithm that makes use of...
39 citations
Cites methods from "Design, Implementation, and Demonst..."
...The combination of observedDoppler velocities from the Ka- andW-SACR can be used for generating unfolded Doppler velocities (Torres et al. 2004)....
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TL;DR: The design and the test of an operational (staggered) triple-PRT (pulse repetition time) scheme that was implemented in July 2004 on the French operational C-band Trappes radar has been presented and histograms of errors have been computed.
Abstract: This paper presents the design and the test of an operational (staggered) triple-PRT (pulse repetition time) scheme that was implemented in July 2004 on the French operational C-band Trappes radar. The three interleaved pulse repetition frequencies (PRFs: PRF1, PRF2, and PRF3) that are used have the particularity to be very low and very close to each other (379, 325, and 303 Hz). The associated individual Nyquist velocities, VN1, VN2, and VN3, range between 4 and 5 m s−1 and the corresponding unambiguous distances are between 495 and 395 km. The ratios VN2/VN1 and VN3/VN1 are, respectively, equal to 6/7 and 4/5. The resulting extended Nyquist velocity is equal to 60 m s−1. One month of data (August 2004) representing more than 10 000 plan position indicators (PPIs) of clear-air, convective, and stratiform rain has been analyzed and histograms of errors have been computed. All histograms are symmetrical and show a well-defined peak centered on zero. The error distributions of the dual-PRT (V12, V1...
37 citations
Cites background from "Design, Implementation, and Demonst..."
...Staggered PRT schemes have recently received much attention (Zrnic 1977; Zrnic and Mahapatra 1985; Gray et al. 1989; Sachidananda and Zrnic 2002; Torres et al. 2004; Tabary et al. 2005) for their ability to solve the long-lasting range – velocity dilemma....
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...Given the fact that Nyquist velocities are expressed in terms of ratio of prime integers, the extended Nyquist velocity VN is easy to compute and reads (see the analysis by Torres et al. (2004)) : VN = lcm(6,4)....
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...Although the de-aliasing rules proposed by Torres et al. (2004) are very attractive in that they are very computationally un-expensive, it would be probably complicated to generalize them to a triple-PRT scheme....
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References
More filters
Book•
01 Jan 1965
TL;DR: This chapter discusses the concept of a Random Variable, the meaning of Probability, and the axioms of probability in terms of Markov Chains and Queueing Theory.
Abstract: Part 1 Probability and Random Variables 1 The Meaning of Probability 2 The Axioms of Probability 3 Repeated Trials 4 The Concept of a Random Variable 5 Functions of One Random Variable 6 Two Random Variables 7 Sequences of Random Variables 8 Statistics Part 2 Stochastic Processes 9 General Concepts 10 Random Walk and Other Applications 11 Spectral Representation 12 Spectral Estimation 13 Mean Square Estimation 14 Entropy 15 Markov Chains 16 Markov Processes and Queueing Theory
13,886 citations
Book•
01 Jan 2002
TL;DR: In this paper, the meaning of probability and random variables are discussed, as well as the axioms of probability, and the concept of a random variable and repeated trials are discussed.
Abstract: Part 1 Probability and Random Variables 1 The Meaning of Probability 2 The Axioms of Probability 3 Repeated Trials 4 The Concept of a Random Variable 5 Functions of One Random Variable 6 Two Random Variables 7 Sequences of Random Variables 8 Statistics Part 2 Stochastic Processes 9 General Concepts 10 Random Walk and Other Applications 11 Spectral Representation 12 Spectral Estimation 13 Mean Square Estimation 14 Entropy 15 Markov Chains 16 Markov Processes and Queueing Theory
12,407 citations
Book•
01 Jan 1971
TL;DR: This article reviewed the principles of Doppler radar and emphasized the quantitative measurement of meteorological parameters, and illustrated the relation of radar data and images to atmospheric phenomena such as tornadoes, microbursts, waves, turbulence, density currents, hurricanes, and lightning.
Abstract: This book reviews the principles of Doppler radar and emphasizes the quantitative measurement of meteorological parameters. It illustrates the relation of Doppler radar data and images to atmospheric phenomena such as tornadoes, microbursts, waves, turbulence, density currents, hurricanes, and lightning.
Geared toward upper-level undergraduates and graduate students, this text was written by two scientists at the National Severe Storms Laboratory in Norman, Oklahoma, a division of the National Oceanic and Atmospheric Administration. Topics include electromagnetic waves and propagation, weather signals and their Doppler spectra, weather signal processing, measurements of precipitation and turbulence, and observations of winds and storms as well as fair weather. Radar images and photographs of weather phenomena highlight the text.
2,178 citations
01 Oct 1996
TL;DR: Introduction and philosophy Chinese remainder algorithm in modular computations in algorithmics in bridging computation in coding theory in cryptography tutorial in information theory tutorial in algebra list of mathematical symbols.
Abstract: Introduction and philosophy Chinese remainder algorithm in modular computations in algorithmics in bridging computations in coding theory in cryptography tutorial in information theory tutorial in algebra list of mathematical symbols.
383 citations
TL;DR: In this article, the first two power spectrum moments from the pulse pair covariance are analyzed and the mean frequency estimation from interlaced pulse pairs is compared to provide a continuum of statistics from equispaced tightly correlated to statistically independent pulse pairs.
Abstract: Estimates statistics of the first two power spectrum moments from the pulse pair covariance are analyzed. The input signal is assumed to be colored Gaussian and the noise, white Gaussian. Perturbation formulas for the standard deviation of both mean frequency and spectrum width are applied to a Gaussian shaped power spectrum, and so is a perturbation formula for the bias in the width estimate. Mean frequency estimation from interlaced pulse pairs is presented. Throughout this study, estimators from independent, spaced, and contiguous pulse pairs are compared to provide a continuum of statistics from equispaced tightly correlated to statistically independent pulse pairs.
203 citations