Airborne Pulsed Doppler Radar

Airborne Pulsed Doppler Radar PDF

Author: Guy V. Morris

Publisher: Artech House Publishers

Published: 1988

Total Pages: 464

ISBN-13:

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Presents the basic principles of pulse-doppler radar without resorting to a heavily mathematical treatment. High-, medium-, and low-pulse repetition frequency (PRF) modes are explained and the advantages and disadvantages of each are discussed. Also included are an explanation of the major signal-processing functions of doppler filtering, pulse compression, tracking, synthetic aperture, selection of medium PRFs, and resolving range ambiguities and a discussion of how to predict the performance of a pulse-doppler radar in the presence of noise and clutter. Annotation copyrighted by Book News, Inc., Portland, OR

Pulse Doppler Radar

Pulse Doppler Radar PDF

Author: Clive Alabaster

Publisher: IET

Published: 2012-06-30

Total Pages: 427

ISBN-13: 1891121987

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The book is organized into three parts, each one building on the material of the previous sections. Part I (Chapters 1-8) covers the basic principles to lay sound foundations for the following parts of the book. It emphasizes classic processing techniques, especially the fast Fourier transform (FFT), and microwave engineering issues, antennas, and hardware. The second part of the book deals with the theory and techniques specific to pulse Doppler radar. This is subdivided into Part IIA (Chapters 9-10), which covers high PRF pulse Doppler, and Part IIB (Chapters 11-15), which covers medium PRF pulse Doppler. A major theme is that of PRF selection and optimization, other waveform design issues, and the problem of ghosting. While high and medium PRF pulse Doppler techniques have become synonymous with airborne fire control radars, they are used over a broad spectrum of airborne and surface-based radar applications. Part II does emphasize the airborne radar case, but it does not neglect the surface-based radar. Finally, Part III (Chapters 16-19) presents a series of four case studies. Each of these case studies applies the material of Part II whilst also highlighting additional radar techniques (and, in some cases, non-radar considerations) specific to the application. Such is the prevalence of pulse Doppler radars today; the number of case studies that could have been considered is well into double figures. However, the four presented here suffice to illustrate the wide variety of pulse Doppler radar applications.

Evaluation of a Meteorological Airborne Pulse Doppler Radar

Evaluation of a Meteorological Airborne Pulse Doppler Radar PDF

Author: B. L. Trotter

Publisher:

Published: 1981

Total Pages: 57

ISBN-13:

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An X-Band airborne radar has been modified to provide a Doppler radar capability. The Doppler radar has been tested to prove the system concept usable. Tests were conducted at Norman, Oklahoma, from May 30 to June 9 of 1978 and in Miami, Florida, on December 1 through December 5, 1979. Optimally the tests would have used meteorological targets for measurement of radial velocities, however, most tests had to be conducted with chaff and ground returns. The tests did show that the airborne Doppler radar will measure velocities that are comparable to those measured by a ground based Doppler radar and those that can be computed by a high accuracy inertial navigation system. The error in the measured radial velocities, when compared to other sensors, is much less than the estimated RMS error of 2 meters/second. (Author).

Designing Clutter Rejection Filters with Complex Coefficients for Airborne Pulsed Doppler Weather Radar

Designing Clutter Rejection Filters with Complex Coefficients for Airborne Pulsed Doppler Weather Radar PDF

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-08

Total Pages: 88

ISBN-13: 9781722343798

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Ground clutter interference is a major problem for airborne pulse Doppler radar operating at low altitudes in a look-down mode. With Doppler zero set at the aircraft ground speed, ground clutter rejection filtering is typically accomplished using a high-pass filter with real valued coefficients and a stopband notch centered at zero Doppler. Clutter spectra from the NASA Wind Shear Flight Experiments of l991-1992 show that the dominant clutter mode can be located away from zero Doppler, particularly at short ranges dominated by sidelobe returns. Use of digital notch filters with complex valued coefficients so that the stopband notch can be located at any Doppler frequency is investigated. Several clutter mode tracking algorithms are considered to estimate the Doppler frequency location of the dominant clutter mode. From the examination of night data, when a dominant clutter mode away from zero Doppler is present, complex filtering is able to significantly increase clutter rejection over use of a notch filter centered at zero Doppler. Jamora, Dennis A. Unspecified Center...

Analysis and Improved Design Considerations for Airborne Pulse Doppler Radar Signal Processing in the Detection of Hazardous Windshear

Analysis and Improved Design Considerations for Airborne Pulse Doppler Radar Signal Processing in the Detection of Hazardous Windshear PDF

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-18

Total Pages: 142

ISBN-13: 9781722941369

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High resolution windspeed profile measurements are needed to provide reliable detection of hazardous low altitude windshear with an airborne pulse Doppler radar. The system phase noise in a Doppler weather radar may degrade the spectrum moment estimation quality and the clutter cancellation capability which are important in windshear detection. Also the bias due to weather return Doppler spectrum skewness may cause large errors in pulse pair spectral parameter estimates. These effects are analyzed for the improvement of an airborne Doppler weather radar signal processing design. A method is presented for the direct measurement of windspeed gradient using low pulse repetition frequency (PRF) radar. This spatial gradient is essential in obtaining the windshear hazard index. As an alternative, the modified Prony method is suggested as a spectrum mode estimator for both the clutter and weather signal. Estimation of Doppler spectrum modes may provide the desired windshear hazard information without the need of any preliminary processing requirement such as clutter filtering. The results obtained by processing a NASA simulation model output support consideration of mode identification as one component of a windshear detection algorithm. Lee, Jonggil Unspecified Center AIRBORNE EQUIPMENT; DETECTION; HAZARDS; METEOROLOGICAL RADAR; PULSE DOPPLER RADAR; SIGNAL PROCESSING; STATISTICAL ANALYSIS; WEATHER; WIND SHEAR; WIND VELOCITY; ALGORITHMS; CLUTTER; ERRORS; ESTIMATES; ESTIMATING; HIGH RESOLUTION; LOW ALTITUDE; LOW FREQUENCIES; SIMULATION; SPECTRA...

Introduction to Airborne Radar

Introduction to Airborne Radar PDF

Author: George W. Stimson

Publisher: SciTech Publishing

Published: 1998

Total Pages: 600

ISBN-13:

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An introduction to the subject for non-specialists: engineers, technicians, pilots, and aerospace industry marketing, public relations, and customer support personnel. Also a reference for specialists in the field. The completely rewritten and revised Second Edition updates the original published by the Hughes Aircraft Company.

Localized Optimization and Effectiveness Analysis of Medium PRF Airborne Pulse Doppler Radars in the Turkish Air Force

Localized Optimization and Effectiveness Analysis of Medium PRF Airborne Pulse Doppler Radars in the Turkish Air Force PDF

Author: Haldun Sifa

Publisher:

Published: 2011

Total Pages: 169

ISBN-13:

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The use of different pulse repetition frequencies (PRFs) delivers significantly different behaviors to airborne radars. For instance, the main purpose for using low PRF is to obtain an unambiguous range measurement. However, the tradeoff when using a low PRF is that the measurement of the target's radial velocity is highly ambiguous and can result in missing some target detections. On the other hand, high PRF is used to reduce or eliminate ambiguities in the measurement of radial velocity. A high PRF, however, causes a highly ambiguous range measurement. The true range is resolved by transmitting multiple waveforms with different PRFs. A modified form of pulse Doppler radar that operates at a medium PRF has both range and Doppler shift ambiguities. However, medium PRF is potentially better for detecting aircraft with low closing speeds than high PRF pulse Doppler. This thesis will focus on the effectiveness and localized optimization of medium PRF in airborne pulse Doppler radars, for the Turkish Air Force. This thesis will also present an analysis of medium PRF performance in a low altitude, air-to-air operating environment offering moderate range radar capability and also delivering acceptable range and Doppler resolution within that operating environment.