Biphase codes of lengths 14 through 34 with the optimum matched filter PSLs (peak sidelobe levels) have been found and enumerated. The minimum achievable sidelobe level seems, generally, to increase with code length but is not monotonic with length. Both ISL (integrated sidelobe level) and the PSL of a given code can be improved by the application of mismatched filtering. For many codes, sidelobe suppression resulting in -30 dB PSL and -25 dB ISL is possible with little loss in SNR (signal-to-noise ratio) as compared with the matched filter implementation. Biphase code compressions seem to exhibit a great deal of uniformity in their response to Doppler shift in the case of both matched and mismatched compression filtering.<>
{"title":"Biphase codes with minimum peak sidelobes","authors":"M. Cohen, J. M. Baden, P. Cohen","doi":"10.1109/NRC.1989.47616","DOIUrl":"https://doi.org/10.1109/NRC.1989.47616","url":null,"abstract":"Biphase codes of lengths 14 through 34 with the optimum matched filter PSLs (peak sidelobe levels) have been found and enumerated. The minimum achievable sidelobe level seems, generally, to increase with code length but is not monotonic with length. Both ISL (integrated sidelobe level) and the PSL of a given code can be improved by the application of mismatched filtering. For many codes, sidelobe suppression resulting in -30 dB PSL and -25 dB ISL is possible with little loss in SNR (signal-to-noise ratio) as compared with the matched filter implementation. Biphase code compressions seem to exhibit a great deal of uniformity in their response to Doppler shift in the case of both matched and mismatched compression filtering.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134635568","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}
A syntactic pattern recognition system for applications to radar signal identification is designed, and the performance of the resulting classification system is evaluated. Two different techniques for generating symbolic patterns from radar backscatter signals are considered. The classification utility of the symbolic patterns is assessed in terms of the performance of maximum-likelihood classification of the observed symbol strings. A syntax analysis algorithm that makes use of symbolic patterns derived from radar backscatter measurements is developed from the likelihood function classifier. Performance results obtained from simulated classification experiments for both maximum-likelihood and language-theoretic classifiers are presented.<>
{"title":"Syntactic classification of radar measurements of commercial aircraft","authors":"O. Sands, F. Garber","doi":"10.1109/NRC.1989.47634","DOIUrl":"https://doi.org/10.1109/NRC.1989.47634","url":null,"abstract":"A syntactic pattern recognition system for applications to radar signal identification is designed, and the performance of the resulting classification system is evaluated. Two different techniques for generating symbolic patterns from radar backscatter signals are considered. The classification utility of the symbolic patterns is assessed in terms of the performance of maximum-likelihood classification of the observed symbol strings. A syntax analysis algorithm that makes use of symbolic patterns derived from radar backscatter measurements is developed from the likelihood function classifier. Performance results obtained from simulated classification experiments for both maximum-likelihood and language-theoretic classifiers are presented.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130685337","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}
High-resolution optimal estimation techniques are applied to the problem of radar imaging of rotating objects, sometimes referred to as ISAR (inverse synthetic array radar) imaging. Typical digital range-Doppler processing operations are described, utilizing two spectral estimation techniques. Quality ISAR images have been obtained from such processing, and particular examples, which are based on simulated data generated from point-target models of rotating objects, are shown. The first example is a so-called merry-go-round of 24 point-targets, and the MLM (maximum-likelihood method) algorithm is utilized to process a 3-D range-Doppler image estimate. The second example is a rotating boom along which are located 15 point-targets including a doublet, a triplet, and a quadruplet cluster that require superresolution techniques to resolve in the Doppler domain. It is concluded that superresolution techniques offer a viable alternative to conventional DFT (discrete Fourier transform) ISAR image processing and should permit either higher resolution images from the same data samples or equal-quality images from significantly fewer data samples.<>
{"title":"Superresolution techniques and ISAR imaging","authors":"W. Gabriel","doi":"10.1109/NRC.1989.47614","DOIUrl":"https://doi.org/10.1109/NRC.1989.47614","url":null,"abstract":"High-resolution optimal estimation techniques are applied to the problem of radar imaging of rotating objects, sometimes referred to as ISAR (inverse synthetic array radar) imaging. Typical digital range-Doppler processing operations are described, utilizing two spectral estimation techniques. Quality ISAR images have been obtained from such processing, and particular examples, which are based on simulated data generated from point-target models of rotating objects, are shown. The first example is a so-called merry-go-round of 24 point-targets, and the MLM (maximum-likelihood method) algorithm is utilized to process a 3-D range-Doppler image estimate. The second example is a rotating boom along which are located 15 point-targets including a doublet, a triplet, and a quadruplet cluster that require superresolution techniques to resolve in the Doppler domain. It is concluded that superresolution techniques offer a viable alternative to conventional DFT (discrete Fourier transform) ISAR image processing and should permit either higher resolution images from the same data samples or equal-quality images from significantly fewer data samples.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122204240","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}
Results are presented for an upwind-illumination, low-grazing-angle marine radar sea scatter experiment conducted in the Pacific Ocean. A wide range of wind speeds and directions resulted in nonequilibrium sea conditions, in contrast to a previous Atlantic Ocean experiment in which ocean waves were fully developed. Statistical properties of the radar echoes are parameterized by a dual-Weibull model versus wind speed and are compared with the North Atlantic data. It is concluded that the Pacific results can be regarded as a lower limit case, appropriate to random seas, whereas the North Atlantic results can be regarded as an upper limit for well-developed seas.<>
{"title":"Results of a marine radar sea clutter experiment for non-equilibrium seas","authors":"D.B. Trizna","doi":"10.1109/NRC.1989.47640","DOIUrl":"https://doi.org/10.1109/NRC.1989.47640","url":null,"abstract":"Results are presented for an upwind-illumination, low-grazing-angle marine radar sea scatter experiment conducted in the Pacific Ocean. A wide range of wind speeds and directions resulted in nonequilibrium sea conditions, in contrast to a previous Atlantic Ocean experiment in which ocean waves were fully developed. Statistical properties of the radar echoes are parameterized by a dual-Weibull model versus wind speed and are compared with the North Atlantic data. It is concluded that the Pacific results can be regarded as a lower limit case, appropriate to random seas, whereas the North Atlantic results can be regarded as an upper limit for well-developed seas.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126283538","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}
A description is given of the Advanced Technology Millimeter Wave Seeker Testbed (ATMMWST), which is characterized by: (1) high range resolution (HRR) by using synthetic coherent processing; (2) complete polarization scattering matrix in a circular basis; and (3) dual-plane sum-and-difference monopulse with complex angle processing. The ATMMWST system consists of a seeker, a signal processor, an instrumentation system and data recording system, and an independent line-of-sight reference system (ILOSRS). The system is used in both tower and captive flight programs to collect target signatures and to demonstrate various aspects of the mission scenario. A functional description of the ATMMWST is presented, and attention is given to radar data processing, radar calibration and representation data, and target detection, classification, and identification.<>
{"title":"Advanced Technology MMW Seeker Testbed: a multi-technology demonstration sensor","authors":"G. A. Killen","doi":"10.1109/NRC.1989.47612","DOIUrl":"https://doi.org/10.1109/NRC.1989.47612","url":null,"abstract":"A description is given of the Advanced Technology Millimeter Wave Seeker Testbed (ATMMWST), which is characterized by: (1) high range resolution (HRR) by using synthetic coherent processing; (2) complete polarization scattering matrix in a circular basis; and (3) dual-plane sum-and-difference monopulse with complex angle processing. The ATMMWST system consists of a seeker, a signal processor, an instrumentation system and data recording system, and an independent line-of-sight reference system (ILOSRS). The system is used in both tower and captive flight programs to collect target signatures and to demonstrate various aspects of the mission scenario. A functional description of the ATMMWST is presented, and attention is given to radar data processing, radar calibration and representation data, and target detection, classification, and identification.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114466896","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}
An alternative, more cost-effective approach to cancellation and angle estimation in airborne radars is proposed. A set of preformed, phase-steered, product-pattern monopulse beams are used to form adapted sum ( Sigma ) and difference ( Delta ) beams that yield undistorted target monopulse ratio estimates while nulling both main-beam and sidelobe ECM (electronic countermeasures). The authors consider three approaches to optimal weight calculation. The first is a straightforward sample-matrix-inversion algorithm, which maximizes the signal-to-noise ratio in a prespecified look direction or, equivalently, minimizes the adapted beam residue subject to a unity-gain constraint in the prespecified look direction. The other two approaches to adaptive weight optimization are based on finding the eigenvector with the minimum eigenvalue for modified versions of R (the sample covariance matrix). Results of algorithm performance analysis are presented. The bandwidth effects of phase-steered antennas on the main beam canceller are also discussed.<>
{"title":"Main beam jammer cancellation and target angle estimation with a polarization-agile monopulse antenna","authors":"C. R. Clark","doi":"10.1109/NRC.1989.47623","DOIUrl":"https://doi.org/10.1109/NRC.1989.47623","url":null,"abstract":"An alternative, more cost-effective approach to cancellation and angle estimation in airborne radars is proposed. A set of preformed, phase-steered, product-pattern monopulse beams are used to form adapted sum ( Sigma ) and difference ( Delta ) beams that yield undistorted target monopulse ratio estimates while nulling both main-beam and sidelobe ECM (electronic countermeasures). The authors consider three approaches to optimal weight calculation. The first is a straightforward sample-matrix-inversion algorithm, which maximizes the signal-to-noise ratio in a prespecified look direction or, equivalently, minimizes the adapted beam residue subject to a unity-gain constraint in the prespecified look direction. The other two approaches to adaptive weight optimization are based on finding the eigenvector with the minimum eigenvalue for modified versions of R (the sample covariance matrix). Results of algorithm performance analysis are presented. The bandwidth effects of phase-steered antennas on the main beam canceller are also discussed.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133092656","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}
An algorithm that successfully classifies radar clutter into one of several major categories, including bird, weather, and target classes, is described. Parametric Bayes classification is applied to a set of features derived from the reflection coefficients computed using the multisegment version of Burg's formula. These coefficients are then transformed and grouped to meet the requirements for multivariate Gaussian behavior. The addition of two amplitude-related features aids in distinguishing between point targets and distributed clutter. Average probabilities of correct classification of 70% to 90% have been found when testing the classifier on recorded radar data.<>
{"title":"A statistical radar clutter classifier","authors":"W. Stehwien, S. Haykin","doi":"10.1109/NRC.1989.47635","DOIUrl":"https://doi.org/10.1109/NRC.1989.47635","url":null,"abstract":"An algorithm that successfully classifies radar clutter into one of several major categories, including bird, weather, and target classes, is described. Parametric Bayes classification is applied to a set of features derived from the reflection coefficients computed using the multisegment version of Burg's formula. These coefficients are then transformed and grouped to meet the requirements for multivariate Gaussian behavior. The addition of two amplitude-related features aids in distinguishing between point targets and distributed clutter. Average probabilities of correct classification of 70% to 90% have been found when testing the classifier on recorded radar data.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134511457","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}
A microstrip radiating element design for a 10% bandwidth, wide-scan-angle, phased-array antenna is described. The radiating element consists of a single probe-fed circular patch on a thick substrate. The element match is optimized using a waveguide array simulator. A finite array of 108 elements was fabricated to evaluate the array's scan-angle performance. Mutual coupling data were used to compute the element reflection coefficient as a function of frequency and scan angle. The scan angle performance was compared with that obtained using the theoretically computed mutual coupling coefficients of a similar array. Both analytical and measured results showed high voltage standing-wave ratio (VSWR) at wide scan angles. The array's performance with a dielectric cover on the top has been evaluated both analytically and experimentally. The results show improvement in the scan angle performance over 10% bandwidth.<>
{"title":"Improved bandwidth microstrip antenna design for airborne phased arrays","authors":"S. Sanzgiri, B. Powers, J. Hart","doi":"10.1109/NRC.1989.47630","DOIUrl":"https://doi.org/10.1109/NRC.1989.47630","url":null,"abstract":"A microstrip radiating element design for a 10% bandwidth, wide-scan-angle, phased-array antenna is described. The radiating element consists of a single probe-fed circular patch on a thick substrate. The element match is optimized using a waveguide array simulator. A finite array of 108 elements was fabricated to evaluate the array's scan-angle performance. Mutual coupling data were used to compute the element reflection coefficient as a function of frequency and scan angle. The scan angle performance was compared with that obtained using the theoretically computed mutual coupling coefficients of a similar array. Both analytical and measured results showed high voltage standing-wave ratio (VSWR) at wide scan angles. The array's performance with a dielectric cover on the top has been evaluated both analytically and experimentally. The results show improvement in the scan angle performance over 10% bandwidth.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134109593","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}
The authors describe the URR (ultrareliable radar) system, subsystems, software architecture, and reliability and maintainability design. Objectives of the current URR program, which is scheduled to be completed in early FY '90, are also discussed. As originally conceived, the URR program was to develop next-generation radar technology that would exhibit an order of magnitude improvement in reliability over existing radar systems. Since existing systems were exhibiting a mean time between failures (MTBF) of approximately 40 hours, the URR reliability goal was established at 400 hours for a system serial MTBF. The URR program has developed technology applicable to the advanced tactical fighter and F-15/F-16/B-1B updates by integrating advanced receiver/STALO (stable local oscillator) technology with solid-state phased-array active aperture technology and very-high-speed integrated circuit common signal processor technology.<>
{"title":"Advanced technology ultrareliable radar (URR)","authors":"D.E. Lingle, D. P. Mikszan, D. Mukai","doi":"10.1109/NRC.1989.47606","DOIUrl":"https://doi.org/10.1109/NRC.1989.47606","url":null,"abstract":"The authors describe the URR (ultrareliable radar) system, subsystems, software architecture, and reliability and maintainability design. Objectives of the current URR program, which is scheduled to be completed in early FY '90, are also discussed. As originally conceived, the URR program was to develop next-generation radar technology that would exhibit an order of magnitude improvement in reliability over existing radar systems. Since existing systems were exhibiting a mean time between failures (MTBF) of approximately 40 hours, the URR reliability goal was established at 400 hours for a system serial MTBF. The URR program has developed technology applicable to the advanced tactical fighter and F-15/F-16/B-1B updates by integrating advanced receiver/STALO (stable local oscillator) technology with solid-state phased-array active aperture technology and very-high-speed integrated circuit common signal processor technology.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122584864","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}
R.K. Moore, G. Raju, W. Xin, C. Davis, K. Demarest, D.I. Rummer
A 150-MHz coherent radar has been developed for sounding the Antarctic ice cap. The radar has a peak power of 20 W, but it has a chirp gain of 26 and coherent processing gain from 256 to 64000, depending on control settings and application. A low time-bandwidth product was required for the chirp, to allow operation from the surface of the ice with a minimum range of only 250 m. The system uses 17-MHz bandwidth to achieve about 5-m resolution in ice or about 9 m in air. A pair of SAW (surface acoustic wave) dispersive delay lines provide linear FM pulse expansion and compression. The RF and digital portions of the system are described along with the software. The radar was tested successfully in both surface and airborne modes in West Antarctica during December 1987.<>
{"title":"A 150-MHz coherent radar system (ice cap sounding)","authors":"R.K. Moore, G. Raju, W. Xin, C. Davis, K. Demarest, D.I. Rummer","doi":"10.1109/NRC.1989.47613","DOIUrl":"https://doi.org/10.1109/NRC.1989.47613","url":null,"abstract":"A 150-MHz coherent radar has been developed for sounding the Antarctic ice cap. The radar has a peak power of 20 W, but it has a chirp gain of 26 and coherent processing gain from 256 to 64000, depending on control settings and application. A low time-bandwidth product was required for the chirp, to allow operation from the surface of the ice with a minimum range of only 250 m. The system uses 17-MHz bandwidth to achieve about 5-m resolution in ice or about 9 m in air. A pair of SAW (surface acoustic wave) dispersive delay lines provide linear FM pulse expansion and compression. The RF and digital portions of the system are described along with the software. The radar was tested successfully in both surface and airborne modes in West Antarctica during December 1987.<<ETX>>","PeriodicalId":167059,"journal":{"name":"Proceedings of the IEEE National Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115733617","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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