Pub Date : 1995-05-08DOI: 10.1109/RADAR.1995.522587
V. Shteinshleiger, G. Misezhnikov, L. Melnikov
The effect of nonlinear scattering of radio waves (appearance of harmonics and combination frequencies in the scattered wave) by real metallic objects is investigated. The dependence of the nonlinear radar cross section (NRCS) of certain objects on the power flux and frequency of the wave illuminating the object is determined. The influence of the mechanical state of the object on nonlinear scattered waves is evaluated.
{"title":"Study of the effect of nonlinear scattering of radio waves by real metallic objects","authors":"V. Shteinshleiger, G. Misezhnikov, L. Melnikov","doi":"10.1109/RADAR.1995.522587","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522587","url":null,"abstract":"The effect of nonlinear scattering of radio waves (appearance of harmonics and combination frequencies in the scattered wave) by real metallic objects is investigated. The dependence of the nonlinear radar cross section (NRCS) of certain objects on the power flux and frequency of the wave illuminating the object is determined. The influence of the mechanical state of the object on nonlinear scattered waves is evaluated.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125230692","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522577
M. Inggs, A. Robinson
This paper summarizes current research into the applications of neural networks for radar ship target recognition. Three very different neural architectures are investigated and compared, namely; the feedforward network with backpropagation, Kohonen's (1990) supervised learning vector quantization network, and Simpson's (see IEEE Trans on Neural Networks, vol.3, no.5, p.776-787, 1992) fuzzy min-max neural network. In all cases, preprocessing in the form of the Fourier-modified discrete Mellin transform is used as a means of extracting feature vectors which are insensitive to the aspect angle of the radar. Classification tests are based on both simulated and real data. Classification accuracies of up to 93% are reported.
本文综述了神经网络在雷达舰船目标识别中的应用研究现状。研究和比较了三种非常不同的神经结构，即;具有反向传播的前馈网络，Kohonen(1990)的监督学习矢量量化网络，以及Simpson的(见IEEE Trans on Neural Networks, vol.3, no. 5)。(5)模糊最小-最大神经网络。在所有情况下，以傅里叶修正离散Mellin变换的形式进行预处理，作为提取对雷达向角不敏感的特征向量的手段。分类试验基于模拟数据和真实数据。据报道，分类准确率高达93%。
{"title":"Neural approaches to ship target recognition","authors":"M. Inggs, A. Robinson","doi":"10.1109/RADAR.1995.522577","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522577","url":null,"abstract":"This paper summarizes current research into the applications of neural networks for radar ship target recognition. Three very different neural architectures are investigated and compared, namely; the feedforward network with backpropagation, Kohonen's (1990) supervised learning vector quantization network, and Simpson's (see IEEE Trans on Neural Networks, vol.3, no.5, p.776-787, 1992) fuzzy min-max neural network. In all cases, preprocessing in the form of the Fourier-modified discrete Mellin transform is used as a means of extracting feature vectors which are insensitive to the aspect angle of the radar. Classification tests are based on both simulated and real data. Classification accuracies of up to 93% are reported.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131779703","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522528
E. Hanle
Clutter with polarimetric signatures different from expected targets can be suppressed by reception orthogonal to the clutter echo polarization. It is shown that this capability is essentially reduced with targets outside the antenna normal direction. This is demonstrated by an example of chaff surrounding a strongly structured and fluctuating target observed with a uniformly transmitting and receiving planar array. Different combinations of adaptive suppression of chaff with the compensation of these directional influences based on the polarimetric antenna matrices are proposed and the corresponding improvement factors are evaluated. It is shown how this can be implemented within the signal processing after reception and partly before transmission. Advantages and drawbacks are discussed.
{"title":"Adaptive chaff suppression by polarimetry with planar phased arrays at off-broadside","authors":"E. Hanle","doi":"10.1109/RADAR.1995.522528","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522528","url":null,"abstract":"Clutter with polarimetric signatures different from expected targets can be suppressed by reception orthogonal to the clutter echo polarization. It is shown that this capability is essentially reduced with targets outside the antenna normal direction. This is demonstrated by an example of chaff surrounding a strongly structured and fluctuating target observed with a uniformly transmitting and receiving planar array. Different combinations of adaptive suppression of chaff with the compensation of these directional influences based on the polarimetric antenna matrices are proposed and the corresponding improvement factors are evaluated. It is shown how this can be implemented within the signal processing after reception and partly before transmission. Advantages and drawbacks are discussed.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134382219","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522574
J. D. Woll
This paper discusses the use of radar technology for collision warning and other vehicular applications. Radar design difficulties and trade-offs regarding operating frequencies, frequency bandwidth requirements, transmitted power and the use of existing low cost production components are presented. The first commercial production radar system to be marketed, the VORAD system, is discussed and the theory of operation of this radar system is described. A discussion of existing FCC regulations as related to intentional radar radiators and future FCC considerations is provided as well as some insight into international regulatory considerations.
{"title":"VORAD collision warning radar","authors":"J. D. Woll","doi":"10.1109/RADAR.1995.522574","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522574","url":null,"abstract":"This paper discusses the use of radar technology for collision warning and other vehicular applications. Radar design difficulties and trade-offs regarding operating frequencies, frequency bandwidth requirements, transmitted power and the use of existing low cost production components are presented. The first commercial production radar system to be marketed, the VORAD system, is discussed and the theory of operation of this radar system is described. A discussion of existing FCC regulations as related to intentional radar radiators and future FCC considerations is provided as well as some insight into international regulatory considerations.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"265 1-2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134633350","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522627
W. W. Irving, S.M. Verbout
Proposes the concept of road area delimitation to improve the performance of a system that detects ground-based military vehicles in synthetic aperture radar (SAR) imagery. Road area delimitation is a data-reduction procedure that consists of automatically finding roads in the imagery, and subsequently discarding the imagery that is not within some prespecified distance of a road. This initial data-processing step eliminates all false alarms in the discarded region, thereby yielding improved detection performance for cases in which vehicle deployment and movement are restricted to the area near roads. The authors develop an algorithm whose function is to estimate road locations automatically, and show the results of applying this algorithm to actual SAR imagery.
{"title":"False alarm reduction through road area delimitation","authors":"W. W. Irving, S.M. Verbout","doi":"10.1109/RADAR.1995.522627","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522627","url":null,"abstract":"Proposes the concept of road area delimitation to improve the performance of a system that detects ground-based military vehicles in synthetic aperture radar (SAR) imagery. Road area delimitation is a data-reduction procedure that consists of automatically finding roads in the imagery, and subsequently discarding the imagery that is not within some prespecified distance of a road. This initial data-processing step eliminates all false alarms in the discarded region, thereby yielding improved detection performance for cases in which vehicle deployment and movement are restricted to the area near roads. The authors develop an algorithm whose function is to estimate road locations automatically, and show the results of applying this algorithm to actual SAR imagery.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132991062","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522618
M. Wicks, D. Piwinski, P. Li
Extensive investments have made toward the development of adaptive array technology for airborne early warning (AEW) radar applications. A characteristic common to all AEW space-time adaptive processing (STAP) approaches designed to operate in a nonhomogeneous interference environment is that they require an estimate of the statistics of that environment based upon measured data from within the multi-dimensional cancellation space. The signal models on which most STAP schemes are based rely upon the assumption of independent and identically distributed (i.i.d.) reference data. Non-conventional ECM environments can severely alter the i.i.d. assumption, especially over extended sampling windows in range. For a radar system designed to rely upon relatively high cancellation performance, target detection capabilities can be severely degraded. We characterize adaptive array radar performance in such a non-conventional ECM environment.
{"title":"Space-time adaptive processing in modern electronic warfare environments","authors":"M. Wicks, D. Piwinski, P. Li","doi":"10.1109/RADAR.1995.522618","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522618","url":null,"abstract":"Extensive investments have made toward the development of adaptive array technology for airborne early warning (AEW) radar applications. A characteristic common to all AEW space-time adaptive processing (STAP) approaches designed to operate in a nonhomogeneous interference environment is that they require an estimate of the statistics of that environment based upon measured data from within the multi-dimensional cancellation space. The signal models on which most STAP schemes are based rely upon the assumption of independent and identically distributed (i.i.d.) reference data. Non-conventional ECM environments can severely alter the i.i.d. assumption, especially over extended sampling windows in range. For a radar system designed to rely upon relatively high cancellation performance, target detection capabilities can be severely degraded. We characterize adaptive array radar performance in such a non-conventional ECM environment.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115735445","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522584
I. Rusnak, J. Moreshet
The problem of specular reflection from rough correlated surfaces is stated, analyzed and evaluated from analysis of digitized topographic maps. Explicit expressions for some models of the surface's correlation functions are presented in closed formulas and in graphical forms. It is shown that ignoring the correlation may cause an underestimation of the specular multipath. Digitized topographic maps are used to derive the correlation functions of some geographic regions. The results derived from digitized topographic maps show that neither the exponential nor the Gaussian correlation models are generally correct. As a result, the modified specular reflection coefficient, that takes into account the correlation of the surface, is higher with respect to the case when it is assumed that the surface is uncorrelated. The analysis shows that over sea this effect is "felt" only in extreme conditions, i.e. very rough seas. However, overland surfaces, usually, this effect is an important factor in the reflection mechanism.
{"title":"Specular multipath from rough correlated surfaces","authors":"I. Rusnak, J. Moreshet","doi":"10.1109/RADAR.1995.522584","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522584","url":null,"abstract":"The problem of specular reflection from rough correlated surfaces is stated, analyzed and evaluated from analysis of digitized topographic maps. Explicit expressions for some models of the surface's correlation functions are presented in closed formulas and in graphical forms. It is shown that ignoring the correlation may cause an underestimation of the specular multipath. Digitized topographic maps are used to derive the correlation functions of some geographic regions. The results derived from digitized topographic maps show that neither the exponential nor the Gaussian correlation models are generally correct. As a result, the modified specular reflection coefficient, that takes into account the correlation of the surface, is higher with respect to the case when it is assumed that the surface is uncorrelated. The analysis shows that over sea this effect is \"felt\" only in extreme conditions, i.e. very rough seas. However, overland surfaces, usually, this effect is an important factor in the reflection mechanism.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121669916","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522639
A. Kawalec
SAW dispersive delay lines are used for the generation and compression of chirp signals in modern radar systems. The influence of the passband-time duration (BT) product of the chirp signal on the sidelobe level of the compressed signal is presented. By using the best method for designing a periodical dispersive transducer two filters, middleband and wideband, can be used. Theoretical and experimental results of dispersive filters are presented. These techniques are used to design 10 /spl mu/s and 16 /spl mu/s dispersive delay lines, with up to a 100% passband, on quartz and lithium niobate substrates.
{"title":"SAW dispersive delay lines in radar signal processing","authors":"A. Kawalec","doi":"10.1109/RADAR.1995.522639","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522639","url":null,"abstract":"SAW dispersive delay lines are used for the generation and compression of chirp signals in modern radar systems. The influence of the passband-time duration (BT) product of the chirp signal on the sidelobe level of the compressed signal is presented. By using the best method for designing a periodical dispersive transducer two filters, middleband and wideband, can be used. Theoretical and experimental results of dispersive filters are presented. These techniques are used to design 10 /spl mu/s and 16 /spl mu/s dispersive delay lines, with up to a 100% passband, on quartz and lithium niobate substrates.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"11 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131110772","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522613
P. P. Gandhi, E. Cardona, L. Baker
Constant false alarm rate (CFAR) radar detectors designed to operate in Rayleigh distributed clutter do not generally perform satisfactorily in the presence of non-Rayleigh clutter due to their operating in significantly deviated clutter environments and also due to their inability to maintain CFAR in non-Rayleigh clutter. Data collected by high-resolution radars have confirmed the non-Rayleigh nature of certain land and sea clutter, often described by multi-parameter log-normal, Weibull or K-statistic models. In this paper, we investigate two CFAR detectors operating in nonhomogeneous Weibull clutter and multi-target interference. First, estimates of the unknown Weibull clutter parameters are employed to obtain a CFAR detector other than the log-t detector for Weibull clutter. Instead, it is shown that there is a one-to-one correspondence between the log-t detector and the proposed alternative, thus giving statistical justification for the use of the log-t detector in Weibull clutter. Performance characteristics of the log-t detector are then presented in homogeneous as well as nonhomogeneous Weibull clutter and multi-target environment, and detailed comparisons are made.
{"title":"CFAR signal detection in nonhomogeneous Weibull clutter and interference","authors":"P. P. Gandhi, E. Cardona, L. Baker","doi":"10.1109/RADAR.1995.522613","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522613","url":null,"abstract":"Constant false alarm rate (CFAR) radar detectors designed to operate in Rayleigh distributed clutter do not generally perform satisfactorily in the presence of non-Rayleigh clutter due to their operating in significantly deviated clutter environments and also due to their inability to maintain CFAR in non-Rayleigh clutter. Data collected by high-resolution radars have confirmed the non-Rayleigh nature of certain land and sea clutter, often described by multi-parameter log-normal, Weibull or K-statistic models. In this paper, we investigate two CFAR detectors operating in nonhomogeneous Weibull clutter and multi-target interference. First, estimates of the unknown Weibull clutter parameters are employed to obtain a CFAR detector other than the log-t detector for Weibull clutter. Instead, it is shown that there is a one-to-one correspondence between the log-t detector and the proposed alternative, thus giving statistical justification for the use of the log-t detector in Weibull clutter. Performance characteristics of the log-t detector are then presented in homogeneous as well as nonhomogeneous Weibull clutter and multi-target environment, and detailed comparisons are made.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114166235","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 : 1995-05-08DOI: 10.1109/RADAR.1995.522531
Z. Bao, G. Liao, Yuhong Zhang
After analyzing the characteristics of clutter echoes received by a moving airborne radar, a general framework for partially adaptive space time processing (STP) is proposed. In order to reduce the complexity of STP without a large performance degradation, the authors describe a new partial adaptive STP for practical real-time applications with highly tolerant ability in the presence of random array errors.
{"title":"Partially adaptive space-time processing for clutter suppression in airborne radars","authors":"Z. Bao, G. Liao, Yuhong Zhang","doi":"10.1109/RADAR.1995.522531","DOIUrl":"https://doi.org/10.1109/RADAR.1995.522531","url":null,"abstract":"After analyzing the characteristics of clutter echoes received by a moving airborne radar, a general framework for partially adaptive space time processing (STP) is proposed. In order to reduce the complexity of STP without a large performance degradation, the authors describe a new partial adaptive STP for practical real-time applications with highly tolerant ability in the presence of random array errors.","PeriodicalId":326587,"journal":{"name":"Proceedings International Radar Conference","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122530316","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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