Igor R Ivić

Igor R Ivić
University of Oklahoma | ou · Cooperative Institute for Mesoscale Meteorological Studies

PhD

About

67
Publications
7,300
Reads
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412
Citations
Citations since 2016
32 Research Items
314 Citations
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2016201720182019202020212022020406080
Introduction
Igor R Ivić currently works at the Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma. Igor does research in Electronic Engineering and Electrical Engineering. Their current project is 'SENSR/MPAR'.
Additional affiliations
August 1997 - present
University of Oklahoma
Position
  • Researcher

Publications

Publications (67)
Article
The recent advent of polarimetric phased array radars (PPARs) used for weather observations fosters the need to study the radar system effects on the estimates of radar products. The major challenges are the steering angle-dependent biases as well as the cross-coupling effects. To mitigate the latter, a pulse-to-pulse phase coding of transmitted pu...
Article
Full-text available
This article summarizes research and risk reduction that will inform acquisition decisions regarding NOAA’s future national operational weather radar network. A key alternative being evaluated is polarimetric phased-array radar (PAR). Research indicates PAR can plausibly achieve fast, adaptive volumetric scanning, with associated benefits for sever...
Conference Paper
Full-text available
A replacement for the WSR-88D may include a phased array system. However, antenna cross-polar coupling contamination may be a major source of estimate bias in a phased array system. Consequently, signal-processing techniques are required to separate and remove unwanted antenna cross coupling. Moreover, range/velocity ambiguity resolution will still...
Poster
Full-text available
The PAR’s unique digital beamforming capability is exploited by the distributed beams (DB) technique to reduce the scan time, or alternatively to improve the data quality when operating a RPAR. DB is accomplished by synthesizing a wide (spoiled) transmit beam and receiving multiple digital beams (within the transmit beam) as the radar rotates. Retu...
Poster
Full-text available
A replacement for the WSR-88D may include a phased array system. However, antenna cross-polar coupling contamination may be a major source of estimate bias in a phased array system. Consequently, signal-processing techniques are required to separate and remove unwanted antenna cross coupling. Moreover, range/velocity ambiguity resolution will still...
Technical Report
Full-text available
The Advanced Technology Demonstrator (ATD) is a full-size, S-band, planar, proof-of-concept PPAR at the National Weather Radar Testbed (NWRT) in Norman, OK (https://nssl.noaa.gov/tools/radar/atd/). Funded by the National Oceanic and Atmospheric Administration (NOAA) and the Federal Aviation Administration (FAA), the ATD was developed by the Nationa...
Article
Many modern phased-array radars (PARs) are multichannel systems that include multiple receivers for data acquisition. Each channel provides a signal from a group of Transmit/Receive modules comprising a section of the antenna. Channels typically consist of a full receive path, often with an independent local oscillator (LO) clock source. Such arran...
Article
This letter combines a time-domain modeling and simulation method for evaluating the impacts of system modules on polarimetric data quality of phased array weather radars with both theoretical analysis and actual measurements. In the presented phased array radar system simulator (PASIM), the distributed weather returns are modeled by randomly distr...
Conference Paper
Full-text available
Polarimetric phased array radar (PPAR) technology is being considered as one of the candidate platforms for the next generation of weather radars. The unique electronic beam steering capability, inherent in PPAR, provides for the enhanced weather surveillance strategies that are envisioned to improve the weather radar products. However, one of the...
Conference Paper
Full-text available
The Advanced Technology Demonstrator (ATD) is an S-band planar polarimetric phased array radar (PPAR) at the National Severe Storms Laboratory (NSSL) in Norman, OK. It serves as a testbed for evaluating the suitability of PPAR technology for weather observations. The major challenge to PPAR weather observations is the calibration needed to produce...
Conference Paper
Full-text available
The Advanced Technology Demonstrator (ATD) is an S-band planar polarimetric phased array radar (PPPAR) being funded through a joint collaboration of the National Oceanic and Atmospheric Administration and the Federal Aviation Administration and developed by the National Severe Storms Laboratory (NSSL), MIT Lincoln Laboratory, and General Dynamics....
Poster
Full-text available
The Advanced Technology Demonstrator (ATD) is an S-band planar polarimetric phased array radar (PPPAR) being funded through a joint collaboration of the National Oceanic and Atmospheric Administration and the Federal Aviation Administration and developed by the National Severe Storms Laboratory (NSSL), MIT Lincoln Laboratory, and General Dynamics....
Conference Paper
Full-text available
The National Oceanic and Atmospheric Administration (NOAA) has identified evolutionary radar mission capabilities aimed at addressing current and future mission needs to support National Weather Service warning operations. Important requirements driving the next generation of weather surveillance radars include improvements in data quality, access...
Poster
Full-text available
The Advanced Technology Demonstrator (ATD) is an S-band planar polarimetric phased array radar (PPPAR) being funded through a joint collaboration of the National Oceanic and Atmospheric Administration and the Federal Aviation Administration and developed by the National Severe Storms Laboratory (NSSL), MIT Lincoln Laboratory, and General Dynamics....
Poster
Full-text available
Differential reflectivity is one of the most important polarimetric variables and is used for scatterer discrimination as well as precipitation rate estimation. It is defined as the ratio of horizontal (H) and vertical (V) signal powers. In its direct form (i.e., as unitless ratio denoted as Zdr) it is used primarily for precipitation rate estimati...
Article
Estimates of copolar correlation coefficient | ρ hv (0)| are one of the essential products generated by polarimetric weather radars because they are used to discriminate among different scatterer types. In theory, estimates of | ρ hv (0)| take values between zero and one. But, statistical errors may cause the estimates to take values that are outsi...
Poster
Full-text available
The NOAA Natonal Severe Storms Laboratory is completng the installaton of the Advanced Technology Demonstrator (ATD), a full-scale, dual-polarizaton, S-band, actve planar phased array weather/air trafc radar. Calibraton to achieve satsfactory polarimetric performance remains among the greatest risks for dual-polarizaton phased array weather radars....
Poster
Full-text available
The goal of a Spectrum Efficient National Surveillance Radar (SENSR) initiative in the U.S. is to explore solutions for vacating the 1.3-1.35 GHz radio frequency band (currently occupied by the FAA/DoD/DHS systems) so that it can be auctioned to the private sector. One option is the Multifunction Phased Array Radar (MPAR) which seeks to combine the...
Conference Paper
Full-text available
The goal of a Spectrum Efficient National Surveillance Radar (SENSR) initiative is to explore solutions for vacating the 1.3-1.35 GHz radio frequency band (currently occupied by the FAA/DoD/DHS systems) so that it can be auctioned to the private sector. One option is the Multifunction Phased Array Radar (MPAR) which seeks to combine the aircraft de...
Article
One option for the improvement of weather radar technology is the use of dual-polarized phased-array radar for weather observations. Several risk factors on this path have been identified and one of the most important ones is the existence of significant cross-polar patterns inherent to the phased-array antenna. These antenna patterns induce cross-...
Presentation
In 2016, the FAA, NOAA, Department of Defense (DoD) and Department of Homeland Security (DHS) initiated a feasibility study for a Spectrum Efficient National Surveillance Radar (SENSR). The goal is to assess approaches for vacating the 1.3 to 1.35 GHz radio frequency band currently allocated to FAA/DoD/DHS “Long Range Radars (LRR)”, so that this ba...
Poster
Full-text available
The Spectrum Efficient National Surveillance Radar (SENSR) program is exploring the feasibility of combining the functions of multiple national aircraft and weather surveillance radar networks into a single network of polarimetric phased array radar (PPAR) systems. One of the main challenges on this path is the use of PPAR for weather observations....
Poster
Full-text available
Because phased array radar (PAR) technology supports more flexible scanning strategies than radars using mechanically steered antennas (resulting in reduced data update times), this technology has been proposed as a foundation for the development of the next generation weather surveillance systems in the USA. Furthermore, the Spectrum Efficient Nat...
Article
One of the main challenges to the use of phased array radar for weather observations is the implementation of dual-polarization with acceptable errors of polarimetric variable estimates. This is because the differences between the copolar antenna patterns at the horizontal and vertical polarizations, as well as cross-polar fields, can introduce una...
Article
One of the main challenges to the use of phased array radar for weather observations is the implementation of dual polarization with acceptable levels of cross-polar fields induced by the antenna. For example, to achieve acceptable differential reflectivity bias (i.e., less than 0.1 dB) using simultaneous transmission and reception of horizontally...
Article
Copolar correlation coefficient is one of the essential polarimetric variables because it enhances the ability of weather radars to discriminate among different hydrometeor types as well as nonmeteorological scatterers. Theoretical values of the copolar correlation coefficient (|ρhv(0)|) are between zero and one, but due to statistical errors, esti...
Article
A radar simulator capable of generating time series data for a polarimetric phased array weather radar has been designed and implemented. The received signals are composed from a high-resolution numerical prediction weather model. Thousands of scattering centers (SCs), each with an independent randomly generated Doppler spectrum, populate the field...
Article
One of the main challenges to the use of phased array radar for weather observations is the implementation of dual polarization with acceptable levels of cross-polar fields induced by the antenna. For example, to achieve acceptable differential reflectivity (ZDR) bias (e.g., less than 0.1 dB) using simultaneous transmission and reception ofHand V p...
Conference Paper
Full-text available
1. ABSTRACT The Multi-function Phased Array Radar (MPAR) program is exploring the feasibility of combining the functions of several national radar networks into a single radar system delivering the required performance for aircraft and weather surveillance. One of the main challenges to the use of phased-array antennas for weather observations is i...
Article
This paper describes the latest adaptive scanning and multifunction capabilities of the National Weather Radar Testbed Phased-Array Radar located in Norman, Oklahoma (USA). Proof-of-concept focused and tailored observations of weather and scheduling algorithms for multifunction operation are described, and their performance is illustrated with real...
Article
One of the main challenges to the use of phased array radar for weather observations is the implementation of dual polarization with acceptable levels of cross-polar fields induced by the antenna. For example, to achieve acceptable differential reflectivity (ZDR) bias (i.e., less than 0.1 dB) using simultaneous transmission and reception of horizon...
Conference Paper
Full-text available
The cross-correlation coefficient (herein referred to as correlation coefficient) is one of the main polarimetric variables. It is used for recognition of the types of radar echoes and in separation of returns from rain and snow. The latter requires precise measurements of the correlation coefficient in areas with low and moderate signal-to-noise (...
Conference Paper
Full-text available
The next step in the evolution of weather observations is the adoption of phased array technology. It provides for electronic beam steering which enables simultaneous survey of the atmosphere while detecting and tracking aircraft. One of the main challenges to the use of phased array technology for weather observations is the implementation of dual...
Conference Paper
Full-text available
The cross-correlation coefficient (herein referred to as correlation coefficient) is one of the main polarimetric variables, and is used for classification of radar echoes, such as separation of returns from rain and snow. Accurate discrimination of hydrometeor types requires precise measurements of the correlation coefficient in areas with low and...
Article
Full-text available
A weather surveillance radar antenna intercepts thermal radiation from various sources, including the ground, the sun, the sky, and precipitation. In the radar receiver, this external radiation produces noise that adds to the receiver internal noise and results in the system noise power varying with the antenna position. If these variations are not...
Article
Full-text available
In Doppler weather radars, signals may exhibit coherency in sample-time whereas noise does not. Additionally, in dual-polarized radars, samples of precipitation echo obtained in the two orthogonally polarized channels are substantially more correlated than samples of noise. Therefore, estimates of auto and cross-correlations can be used individuall...
Article
Full-text available
Examined are two related modes of polarimetric signal transmission that reduce coupling between the orthogonal components of received signals. For the surveillance scan with large unambiguous range and the simultaneous mode of horizontal (H) and vertical (V) transmission, pulse-to-pulse coding is suggested. It relaxes conditions on cross-coupling i...
Conference Paper
Phased array technology has been used to for aircraft detection and tracking for years. More recently, this same technology has been demonstrated on the National Weather Radar Testbed (NWRT) for rapid scanning of weather phenomena. Consequently, this technology can serve as a proving ground for the Multi-function Phased Array Radar (MPAR) network o...
Conference Paper
This paper describes the latest adaptive scanning capabilities of the National Weather Radar Testbed Phased-Array Radar located in Norman, OK. Focused observations, tailored observations, and the required scheduling algorithms are introduced, and their performance is illustrated with real-data examples. It is demonstrated that adaptive scanning for...
Conference Paper
Full-text available
The copolar correlation coefficient is one of the main polarimetric variables. It is used for recognition of the types of radar echoes and in separation of returns from rain and snow. The latter requires precise measurements of the correlation coefficient in areas with low and moderate signal-to-noise ratios. Correlation coefficient estimates are u...
Conference Paper
Full-text available
This paper starts by identifying one of the most challenging requirements for agile beam phased array weather radars (PARs). It is quantitative measurement of polarimetric variables to a distance of 300 km with no ambiguities in range whatsoever. Such measurement is now routine on the WSR-88D of the National Weather Service. To match this performan...
Conference Paper
Full-text available
Fast adaptive weather scanning was first demonstrated on the National Weather Radar Testbed (NWRT) Phased Array Radar (PAR) in 2009 with the implementation of the Adaptive Digital Signal Processing Algorithm for Phased-Array Radar Timely Scans (ADAPTS). The algorithm provides spatially focused weather observations to reduce volumetric scanning time...
Article
Full-text available
A radar antenna intercepts thermal radiation from various sources including the ground, the sun, the sky, precipitation, and man-made radiators. In the radar receiver, this external radiation produces noise that constructively adds to the receiver internal noise and results in the overall system noise. Consequently, the system noise power is depend...
Technical Report
Full-text available
Executive Summary-The next step in the evolution of weather observations is the adoption of phased array technology. It provides for electronic beam steering which enables simultaneous surveillance of the atmosphere while detecting and tracking aircraft. To successfully accomplish the weather surveillance mission, the phased array radar (PAR) will...
Conference Paper
The U.S. Government operates seven distinct radar networks providing weather and aircraft surveillance for public weather services, air traffic control, and homeland defense. A next-generation, multifunction phased array radar (MPAR) concept has been proposed that could provide enhanced weather and aircraft surveillance services with potentially lo...
Article
When the National Weather Radar Testbed (NWRT) was installed in 2004, a single-channel digital receiver was implemented so that the radar could mimic typical Weather Surveillance Radar (WSR) version 1988 Doppler (WSR-88D) capability. This, however, left unused eight other channels, built into the antenna. This paper describes the hardware instrumen...
Article
Full-text available
It is customary to censor signals in conventional weather radar using estimates of signal-to-noise ratio (SNR) and/or magnitude of autocorrelation coefficient at lag one. Dual-polarized weather radar provides a pair of highly correlated signals from the two orthogonally polarized returns. A novel censoring technique, previously proposed, sums power...
Conference Paper
Full-text available
Currently the WSR-88D network of weather surveillance radars (i.e., NEXRAD) uses only power estimates for signal censoring. The planned network upgrade to dual polarization will result in 3dB SNR reduction because transmitter output will be split between horizontal and vertical channels. As a result, this will diminish radar sensitivity if the curr...
Article
The first phased array radar dedicated to weather observation and analysis is now instrumented with eight, simultaneous digital receivers. The multi-channel receiver will collect signals from the sum, azimuth-difference, elevation- difference, and five broad-beamed auxiliary channels. The multi-channel receiver will allow the direct implementation...
Conference Paper
Full-text available
Radar antenna intercepts thermal radiation from various sources including ground, precipitation, sun, sky, or man-made radiators. Consequently, depending on where the antenna is pointing, the receiver noise power will vary routinely. This creates possibility for incorrect noise power measurements which may lead to reduction of coverage in cases whe...
Poster
Full-text available
Radar antenna intercepts thermal radiation from various sources including ground, precipitation, sun, sky, or man-made radiators. Consequently, depending on where the antenna is pointing, the receiver noise power will vary routinely. This creates possibility for incorrect noise power measurements which may lead to reduction of coverage in cases whe...
Conference Paper
Full-text available
The first phased array radar dedicated to weather observation and analysis is now instrumented with eight, simultaneous digital receivers. The addition of these additional channels will enable the use of advanced signal processing to improve signal/clutter in an adaptive mode. Elimination of strong point and ground clutter returns from the low-leve...
Article
Full-text available
Currently, signal detection and censoring in operational weather radars is performed by using thresholds of the estimated signal-to-noise ratio (SNR) and/or the magnitude of the autocorrelation coefficient at the first temporal lag. The growing popularity of polarimetric radars prompts the quest for improved detection schemes that take advantage of...
Conference Paper
Full-text available
Presently, the Signal-to-Noise-Ratio (SNR) measurement is used to determine the presence of a weather signal for Weather Surveillance Radar – 1988 Doppler (WSR-88D). Growing popularity of polarimetric radars prompts the need for improved signal detection scheme. Namely, the ongoing upgrade of the WSR-88D network to dual polarization results in a 3...
Conference Paper
Full-text available
Whitening of oversampled signals in range has been recently proposed to improve the performance of spectral moment estimators on Doppler weather radars. The proven method decorrelates signals by grouping samples along range in blocks (i.e., vectors) and applying a whitening matrix to each block. Implementation of such matrix multiplication is suite...
Article
Full-text available
Demonstration of a method for improved Doppler spectral moment estimation is made on NOAA's research and development Weather Surveillance Radar-1988 Doppler (WSR-88D) in Norman, Oklahoma. Time series data have been recorded using a commercial processor and digital receiver whereby the sampling frequency is several times larger than the reciprocal o...
Article
This paper describes the status of a project that will simultaneously digitize the radar signals coming from eight channels on the phased array antenna at the Na- tional Weather Radar Testbed (NWRT) in Norman, Ok- lahoma. At the current time, a single-channel digital receiver is operational on this S-band radar to mimic the current WSR-88D capabili...

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