Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201192
Y. Kwag
An adaptive technique for generating filter weight for the rejection of clutter and interference with unknown spectral statistics is presented. The adaptive processor generates the average weight vector in the sense of the minimum residue noise power based on the injected noise-level vector in the weight control algorithm. This can be utilized to identify and reject an unknown sequence of the clutter signal without making use of a modeling procedure. The generated weights using the clutter signal returned from a particular azimuth-range space can be stored and updated at the subsequent scan in the same azimuth-range space. The effect of clutter residue noise is on the null adaptation rate and the system improvement factor is examined. Simulation results show the effectiveness of the proposed method in the changing clutter and interference rejection capability. The digital signal processing implementation concept is suggested for this processor.<>
{"title":"Adaptive suppression of changing clutter and interference with unknown spectral statistics in the sense of minimum residue noise power","authors":"Y. Kwag","doi":"10.1109/RADAR.1990.201192","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201192","url":null,"abstract":"An adaptive technique for generating filter weight for the rejection of clutter and interference with unknown spectral statistics is presented. The adaptive processor generates the average weight vector in the sense of the minimum residue noise power based on the injected noise-level vector in the weight control algorithm. This can be utilized to identify and reject an unknown sequence of the clutter signal without making use of a modeling procedure. The generated weights using the clutter signal returned from a particular azimuth-range space can be stored and updated at the subsequent scan in the same azimuth-range space. The effect of clutter residue noise is on the null adaptation rate and the system improvement factor is examined. Simulation results show the effectiveness of the proposed method in the changing clutter and interference rejection capability. The digital signal processing implementation concept is suggested for this processor.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123501869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201162
D. Maurer, S.C. Lee, A.R. Bodnar, T. Lewandowski, T. Keast
A model has been developed to explain unusual sea clutter Doppler frequency spectral characteristics that were observed from search radars operating in ducting conditions. Sea returns from arctic coastal sites exhibit extreme mean Doppler frequency shifts, with the magnitudes of the means varying from one ocean area to another. The spectrum bandwidth for the individual returns was very narrow, even though the mean value was large. Clutter spectra collected from a Middle East site exhibited similar anomalies. Both data sets were collected during calm (almost glassy) seas, so breaking waves and surface turbulence were not responsible for the unusual characteristics. A physical mechanism is hypothesized to explain how the interaction between a moving ocean surface and propagating electromagnetic energy in a surface duct can induce large Doppler shifts in sea clutter spectra. Model simulations support the hypothesis and compare favorably with measured data.<>
{"title":"Modeling the spectral structure of ducted sea clutter","authors":"D. Maurer, S.C. Lee, A.R. Bodnar, T. Lewandowski, T. Keast","doi":"10.1109/RADAR.1990.201162","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201162","url":null,"abstract":"A model has been developed to explain unusual sea clutter Doppler frequency spectral characteristics that were observed from search radars operating in ducting conditions. Sea returns from arctic coastal sites exhibit extreme mean Doppler frequency shifts, with the magnitudes of the means varying from one ocean area to another. The spectrum bandwidth for the individual returns was very narrow, even though the mean value was large. Clutter spectra collected from a Middle East site exhibited similar anomalies. Both data sets were collected during calm (almost glassy) seas, so breaking waves and surface turbulence were not responsible for the unusual characteristics. A physical mechanism is hypothesized to explain how the interaction between a moving ocean surface and propagating electromagnetic energy in a surface duct can induce large Doppler shifts in sea clutter spectra. Model simulations support the hypothesis and compare favorably with measured data.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125490193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201176
D.E. Maron
Frequency-jumped burst (FJB) waveforms for wideband phased-array radars are discussed. These waveforms can avoid or reduce the need for time-delay steering. Fast Fourier transform (FFT)-based stretch processing is a computationally efficient means of compressing FJB. However, this type of system poses several concerns that require attention, including mismatch loss, Doppler sensitivity, and grating lobe time sidelobes. All of these concerns are mitigated for small range windows and small Doppler offsets. The grating lobe concern can be overcome by using nonperiodic FJB.<>
{"title":"Frequency-jumped burst waveforms with stretch processing","authors":"D.E. Maron","doi":"10.1109/RADAR.1990.201176","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201176","url":null,"abstract":"Frequency-jumped burst (FJB) waveforms for wideband phased-array radars are discussed. These waveforms can avoid or reduce the need for time-delay steering. Fast Fourier transform (FFT)-based stretch processing is a computationally efficient means of compressing FJB. However, this type of system poses several concerns that require attention, including mismatch loss, Doppler sensitivity, and grating lobe time sidelobes. All of these concerns are mitigated for small range windows and small Doppler offsets. The grating lobe concern can be overcome by using nonperiodic FJB.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127351609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201210
D. Peed
The concept of using a small nonscanning Doppler radar, called the weather mini-radar, for automatically detecting and quantitatively measuring low-altitude wind shear along approach and departure paths to airport runways is introduced. This work focuses on the implementation of the weather mini-radar design on a general-purpose pulse Doppler radar computer simulation. This simulation uses microburst model data generated with the aid of a supercomputer as the input, and the output is used to test prototype automatic detection algorithms proposed for use with the weather mini-radar. Test results indicate that the weather mini-radar concept of automating wind shear detection and measurement is sound.<>
{"title":"Simulations of the concept of using a small nonscanning Doppler radar for wind shear detection","authors":"D. Peed","doi":"10.1109/RADAR.1990.201210","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201210","url":null,"abstract":"The concept of using a small nonscanning Doppler radar, called the weather mini-radar, for automatically detecting and quantitatively measuring low-altitude wind shear along approach and departure paths to airport runways is introduced. This work focuses on the implementation of the weather mini-radar design on a general-purpose pulse Doppler radar computer simulation. This simulation uses microburst model data generated with the aid of a supercomputer as the input, and the output is used to test prototype automatic detection algorithms proposed for use with the weather mini-radar. Test results indicate that the weather mini-radar concept of automating wind shear detection and measurement is sound.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130076763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201150
S. Roy, T. Kim, R. Berkowitz, W. Graham, D. Carlson
The application of a short-pulse, high-angular-resolution array focused in the near field for detection and imaging of shallow subsurface objects is discussed. An experimental system based on a forward-looking bistatic radar configuration with a digital synthetic aperture array receiver is described. Beam steering and scanning are accomplished using phase compensation based on simplified models of wave propagation across dielectric interfaces. Reconstructed images based on these models and utilizing real pulse-echo experimental data are included to demonstrate the performance of an L-band system.<>
{"title":"Subsurface radar for detection of buried targets","authors":"S. Roy, T. Kim, R. Berkowitz, W. Graham, D. Carlson","doi":"10.1109/RADAR.1990.201150","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201150","url":null,"abstract":"The application of a short-pulse, high-angular-resolution array focused in the near field for detection and imaging of shallow subsurface objects is discussed. An experimental system based on a forward-looking bistatic radar configuration with a digital synthetic aperture array receiver is described. Beam steering and scanning are accomplished using phase compensation based on simplified models of wave propagation across dielectric interfaces. Reconstructed images based on these models and utilizing real pulse-echo experimental data are included to demonstrate the performance of an L-band system.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129490079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201186
G. C. Rose, J. Hoffman
The effect of system disturbances on the improvement factor of moving target indicator (MTI) processors is discussed. The effects are determined analytically and are confirmed by a simulation of a generic MTI processor. The improvement factor for both point and distributed clutter is considered, with distributed clutter placing the more stringent requirements on system stability. Pulse risetime and different statistical models for the disturbances are considered. Equations and curves relating improvement factor to disturbance allow a system analyst to determine the allowable disturbance to achieve a given improvement factor. A useful rule of thumb for the effect of leading edge jitter on improvement factor, reasonably accurate over a wide range of conditions, is given.<>
{"title":"Effect of leading edge jitter on MTI improvement factor","authors":"G. C. Rose, J. Hoffman","doi":"10.1109/RADAR.1990.201186","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201186","url":null,"abstract":"The effect of system disturbances on the improvement factor of moving target indicator (MTI) processors is discussed. The effects are determined analytically and are confirmed by a simulation of a generic MTI processor. The improvement factor for both point and distributed clutter is considered, with distributed clutter placing the more stringent requirements on system stability. Pulse risetime and different statistical models for the disturbances are considered. Equations and curves relating improvement factor to disturbance allow a system analyst to determine the allowable disturbance to achieve a given improvement factor. A useful rule of thumb for the effect of leading edge jitter on improvement factor, reasonably accurate over a wide range of conditions, is given.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"20 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121009847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201175
J. P. Donohoe, F. Ingels
The ambiguity function characteristics of FSK/PSK (frequency shift keying/phase shift keying) signals based on the Costas frequency hopping technique are presented and compared to those of FSK/PSK signals based on quantized linear frequency modulation. The Costas-based FSK/PSK signal is found to maintain a high Doppler tolerance while yielding instantaneous spreading of the component frequencies along with enhanced range resolution. The question of whether PSK encoding should be performed from frequency to frequency or over each frequency separately is addressed through specific examples. The overall results give the radar designer a much freer hand in the selection of the transmission bandwidth, range resolution, and PRF (pulse repetition frequency) duty cycle.<>
{"title":"The ambiguity properties of FSK/PSK signals","authors":"J. P. Donohoe, F. Ingels","doi":"10.1109/RADAR.1990.201175","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201175","url":null,"abstract":"The ambiguity function characteristics of FSK/PSK (frequency shift keying/phase shift keying) signals based on the Costas frequency hopping technique are presented and compared to those of FSK/PSK signals based on quantized linear frequency modulation. The Costas-based FSK/PSK signal is found to maintain a high Doppler tolerance while yielding instantaneous spreading of the component frequencies along with enhanced range resolution. The question of whether PSK encoding should be performed from frequency to frequency or over each frequency separately is addressed through specific examples. The overall results give the radar designer a much freer hand in the selection of the transmission bandwidth, range resolution, and PRF (pulse repetition frequency) duty cycle.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123369205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201171
J. M. Baden, M. Cohen
A technique for the generation of mismatched filters that minimize the peak sidelobe in the correlation of a biphase code is developed. The technique is applied to several well-known codes, and the resulting sidelobe performance is compared to that of the matched filter and optimal integrated sidelobe level filter. The theory is shown to be applicable to the generation of filters that produce regions within the correlation that are nearly sidelobe-free. These filters may be of use in tracking applications and some specialized surveillance scenarios.<>
{"title":"Optimal peak sidelobe filters for biphase pulse compression","authors":"J. M. Baden, M. Cohen","doi":"10.1109/RADAR.1990.201171","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201171","url":null,"abstract":"A technique for the generation of mismatched filters that minimize the peak sidelobe in the correlation of a biphase code is developed. The technique is applied to several well-known codes, and the resulting sidelobe performance is compared to that of the matched filter and optimal integrated sidelobe level filter. The theory is shown to be applicable to the generation of filters that produce regions within the correlation that are nearly sidelobe-free. These filters may be of use in tracking applications and some specialized surveillance scenarios.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117346426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201169
T. Halpin, H. Urkowitz, D.E. Maron
Certain modifications of the Cobra Dane radar are considered, particularly modernization of the waveform generator. For wideband waveforms, the dispersive effects of the ionosphere become increasingly significant. The technique of predistorting the transmitted waveform so that a linear chirp is received after two-way passage is one way to overcome that dispersion. This approach is maintained for the modified system, but with a specific predistortion waveform well suited to the modification. The appropriate form of predistortion was derived in an implicit form of time as a function of frequency. The exact form was approximated by Taylor series and pseudo-Chebyshev approximation. The latter proved better, as demonstrated by the resulting smaller loss in detection sensitivity, less coarsening of range resolution, and a lower peak sidelobe. The effects of error in determining the plasma delay constant were determined and are given in graphical form. A suggestion for in-place determination of the plasma delay constant is given.<>
{"title":"Propagation compensation by waveform predistortion","authors":"T. Halpin, H. Urkowitz, D.E. Maron","doi":"10.1109/RADAR.1990.201169","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201169","url":null,"abstract":"Certain modifications of the Cobra Dane radar are considered, particularly modernization of the waveform generator. For wideband waveforms, the dispersive effects of the ionosphere become increasingly significant. The technique of predistorting the transmitted waveform so that a linear chirp is received after two-way passage is one way to overcome that dispersion. This approach is maintained for the modified system, but with a specific predistortion waveform well suited to the modification. The appropriate form of predistortion was derived in an implicit form of time as a function of frequency. The exact form was approximated by Taylor series and pseudo-Chebyshev approximation. The latter proved better, as demonstrated by the resulting smaller loss in detection sensitivity, less coarsening of range resolution, and a lower peak sidelobe. The effects of error in determining the plasma delay constant were determined and are given in graphical form. A suggestion for in-place determination of the plasma delay constant is given.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131513960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201155
E. Christensen, Søren Nørvang Madsen, Niels Skou
The merits of using homodyne techniques for coherent radar are examined. The influence of various component deficiencies is discussed with relation to the choice between homodyne and heterodyne. The use of digital IQ signal generation and processing to correct for some of the problems of modulator and demodulator design by predistortion, offset correction, etc. is briefly addressed. A 5.3 GHz synthetic aperture radar designed for strip mapping at high resolution is then considered to illustrate the use of the homodyne approach. Measurement results on quadrature modulators and demodulators at 300 MHz and 5.3 GHz are given to support the contention that the homodyne technique can be applied successfully.<>
{"title":"Review of the homodyne technique for coherent radar","authors":"E. Christensen, Søren Nørvang Madsen, Niels Skou","doi":"10.1109/RADAR.1990.201155","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201155","url":null,"abstract":"The merits of using homodyne techniques for coherent radar are examined. The influence of various component deficiencies is discussed with relation to the choice between homodyne and heterodyne. The use of digital IQ signal generation and processing to correct for some of the problems of modulator and demodulator design by predistortion, offset correction, etc. is briefly addressed. A 5.3 GHz synthetic aperture radar designed for strip mapping at high resolution is then considered to illustrate the use of the homodyne approach. Measurement results on quadrature modulators and demodulators at 300 MHz and 5.3 GHz are given to support the contention that the homodyne technique can be applied successfully.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"242 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114452443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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