Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722880187
Category :
Languages : en
Pages : 42
Book Description
The pulse pair method for spectrum parameter estimation is commonly used in pulse Doppler weather radar signal processing since it is economical to implement and can be shown to be a maximum likelihood estimator. With the use of airborne weather radar for windshear detection, the turbulent weather and strong ground clutter return spectrum differs from that assumed in its derivation, so the performance robustness of the pulse pair technique must be understood. Here, the effect of radar system pulse to pulse phase jitter and signal spectrum skew on the pulse pair algorithm performance is discussed. Phase jitter effect may be significant when the weather return signal to clutter ratio is very low and clutter rejection filtering is attempted. The analysis can be used to develop design specifications for airborne radar system phase stability. It is also shown that the weather return spectrum skew can cause a significant bias in the pulse pair mean windspeed estimates, and that the poly pulse pair algorithm can reduce this bias. It is suggested that use of a spectrum mode estimator may be more appropriate in characterizing the windspeed within a radar range resolution cell for detection of hazardous windspeed gradients. Baxa, Ernest G., Jr. and Lee, Jonggil Unspecified Center NAG1-928; RTOP 505-64-12-02...
The Pulse-Pair Algorithm As a Robust Estimator of Turbulent Weather Spectral Parameters Using Airborne Pulse Doppler Radar
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722880187
Category :
Languages : en
Pages : 42
Book Description
The pulse pair method for spectrum parameter estimation is commonly used in pulse Doppler weather radar signal processing since it is economical to implement and can be shown to be a maximum likelihood estimator. With the use of airborne weather radar for windshear detection, the turbulent weather and strong ground clutter return spectrum differs from that assumed in its derivation, so the performance robustness of the pulse pair technique must be understood. Here, the effect of radar system pulse to pulse phase jitter and signal spectrum skew on the pulse pair algorithm performance is discussed. Phase jitter effect may be significant when the weather return signal to clutter ratio is very low and clutter rejection filtering is attempted. The analysis can be used to develop design specifications for airborne radar system phase stability. It is also shown that the weather return spectrum skew can cause a significant bias in the pulse pair mean windspeed estimates, and that the poly pulse pair algorithm can reduce this bias. It is suggested that use of a spectrum mode estimator may be more appropriate in characterizing the windspeed within a radar range resolution cell for detection of hazardous windspeed gradients. Baxa, Ernest G., Jr. and Lee, Jonggil Unspecified Center NAG1-928; RTOP 505-64-12-02...
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722880187
Category :
Languages : en
Pages : 42
Book Description
The pulse pair method for spectrum parameter estimation is commonly used in pulse Doppler weather radar signal processing since it is economical to implement and can be shown to be a maximum likelihood estimator. With the use of airborne weather radar for windshear detection, the turbulent weather and strong ground clutter return spectrum differs from that assumed in its derivation, so the performance robustness of the pulse pair technique must be understood. Here, the effect of radar system pulse to pulse phase jitter and signal spectrum skew on the pulse pair algorithm performance is discussed. Phase jitter effect may be significant when the weather return signal to clutter ratio is very low and clutter rejection filtering is attempted. The analysis can be used to develop design specifications for airborne radar system phase stability. It is also shown that the weather return spectrum skew can cause a significant bias in the pulse pair mean windspeed estimates, and that the poly pulse pair algorithm can reduce this bias. It is suggested that use of a spectrum mode estimator may be more appropriate in characterizing the windspeed within a radar range resolution cell for detection of hazardous windspeed gradients. Baxa, Ernest G., Jr. and Lee, Jonggil Unspecified Center NAG1-928; RTOP 505-64-12-02...
The Pulse-pair Algorithm as a Robust Estimator of Turbulent Weather Spectral Parameters Using Airborne Pulse Doppler Radar
Author: Ernest Granville Baxa
Publisher:
ISBN:
Category : Doppler radar
Languages : en
Pages : 44
Book Description
Publisher:
ISBN:
Category : Doppler radar
Languages : en
Pages : 44
Book Description
Scientific and Technical Aerospace Reports
Airborne Wind Shear Detection and Warning Systems: Third Combined Manufacturers' and Technologists' Conference, Part 2
Airborne Wind Shear Detection and Warning Systems: Fourth Combined Manufacturers' and Technologists' Conference, Part 1
Analysis and Improved Design Considerations for Airborne Pulse Doppler Radar Signal Processing in the Detection of Hazardous Windshear
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722941369
Category :
Languages : en
Pages : 142
Book Description
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...
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722941369
Category :
Languages : en
Pages : 142
Book Description
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...
Spectrum Modal Analysis for the Detection of Low-altitude Windshear with Airborne Doppler Radar
AMS Newsletter
Author: American Meteorological Society
Publisher:
ISBN:
Category : Meteorology
Languages : en
Pages : 202
Book Description
Publisher:
ISBN:
Category : Meteorology
Languages : en
Pages : 202
Book Description
NASA's Contributions to Aeronautics: Flight environment, operations, flight testing, and research
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1064
Book Description
Two-volume collection of case studies on aspects of NACA-NASA research by noted engineers, airmen, historians, museum curators, journalists, and independent scholars. Explores various aspects of how NACA-NASA research took aeronautics from the subsonic to the hypersonic era.-publisher description.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1064
Book Description
Two-volume collection of case studies on aspects of NACA-NASA research by noted engineers, airmen, historians, museum curators, journalists, and independent scholars. Explores various aspects of how NACA-NASA research took aeronautics from the subsonic to the hypersonic era.-publisher description.