Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201204
E. Hung, J. E. Morris
A technique to refine target elevation estimates by modifying the antenna calibration table is described. The data were measured with an array antenna and low-level aircraft flying over water. An optical tracker mounted close to the antenna provided an independent measure of the target elevation. In data measurement, there was an unknown error source which produced a date-dependent offset in the antenna boresight direction. A previous analysis of the data, using the singular value decomposition method, found that there were false tracks branching out from the target and image tracks. The modified calibration table significantly reduces both the number of these false tracks and the scattering of the estimates close to the output target tracks. It also reveals that the gradient of the output target track was less negative than that of the optical track. A possible link between this property and the data-dependence of the offset in antenna boresight direction is discussed.<>
{"title":"A technique to refine the elevation estimates in low-angle tracking data measured with an array antenna","authors":"E. Hung, J. E. Morris","doi":"10.1109/RADAR.1990.201204","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201204","url":null,"abstract":"A technique to refine target elevation estimates by modifying the antenna calibration table is described. The data were measured with an array antenna and low-level aircraft flying over water. An optical tracker mounted close to the antenna provided an independent measure of the target elevation. In data measurement, there was an unknown error source which produced a date-dependent offset in the antenna boresight direction. A previous analysis of the data, using the singular value decomposition method, found that there were false tracks branching out from the target and image tracks. The modified calibration table significantly reduces both the number of these false tracks and the scattering of the estimates close to the output target tracks. It also reveals that the gradient of the output target track was less negative than that of the optical track. A possible link between this property and the data-dependence of the offset in antenna boresight direction is discussed.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"39 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":"117184434","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.1990.201187
C. Oliver, R. White
The problem of the classification of clutter textures in coherent images, e.g. synthetic aperture radar (SAR), is discussed. The first stage in such a process is to segment the observed texture into regions of differing texture properties. In order to select the segmentation regions one must exploit some information about the properties of the texture. One method for encapsulating this information is in the form of a model which is known a priori. Another approach is to train a segmentation method by large numbers of examples of the types of texture encountered. This latter approach underlies the use of noncommittal neural networks. A comparison of these approaches reveals the extent to which a neural network is capable of extracting all the information contained within the texture which is automatically exploited in the model-based approach.<>
{"title":"Radar clutter classification based on noise models and neural networks","authors":"C. Oliver, R. White","doi":"10.1109/RADAR.1990.201187","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201187","url":null,"abstract":"The problem of the classification of clutter textures in coherent images, e.g. synthetic aperture radar (SAR), is discussed. The first stage in such a process is to segment the observed texture into regions of differing texture properties. In order to select the segmentation regions one must exploit some information about the properties of the texture. One method for encapsulating this information is in the form of a model which is known a priori. Another approach is to train a segmentation method by large numbers of examples of the types of texture encountered. This latter approach underlies the use of noncommittal neural networks. A comparison of these approaches reveals the extent to which a neural network is capable of extracting all the information contained within the texture which is automatically exploited in the model-based approach.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"270 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":"115416676","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.1990.201202
J. Kramer, W. S. Reid
A real-time feasible track-before-detect process for a scanning pulsed Doppler airborne-type radar is described. Robust distribution-free based ranking is applied in range separately for each Doppler. A dynamic programming process is used to select a best tentative track passing through each range, azimuth, and Doppler cell. The process sequentially optimizes smoothed rank as the field of view is scanned. Results of a simulation are presented for a system with multiple bursts at a given pulse repetition frequency. Track detections are obtained with probability 0.5 at a signal-to-noise ratio of about 5 dB for a Rician signal pulse noise model as measured at the Doppler outputs. The corresponding false track generation rate is estimated to be 5*10/sup -5/ per processed resolution cell.<>
{"title":"Track-before-detect processing for an airborne type radar","authors":"J. Kramer, W. S. Reid","doi":"10.1109/RADAR.1990.201202","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201202","url":null,"abstract":"A real-time feasible track-before-detect process for a scanning pulsed Doppler airborne-type radar is described. Robust distribution-free based ranking is applied in range separately for each Doppler. A dynamic programming process is used to select a best tentative track passing through each range, azimuth, and Doppler cell. The process sequentially optimizes smoothed rank as the field of view is scanned. Results of a simulation are presented for a system with multiple bursts at a given pulse repetition frequency. Track detections are obtained with probability 0.5 at a signal-to-noise ratio of about 5 dB for a Rician signal pulse noise model as measured at the Doppler outputs. The corresponding false track generation rate is estimated to be 5*10/sup -5/ per processed resolution cell.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"43 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":"115509539","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.1990.201196
John E. Gray
The formalism for computing the Doppler spectrum for perfectly reflecting mirrors undergoing various types of accelerations is reviewed. This method is an amplification of work done by D. Censor and J. Cooper for one-dimensional waves. For sinusoidal waves, the formalism provides a computationally easy algorithm that enables determination of the Doppler spectrum. This method is exact and does not ignore the effects of motion on the amplitude, as is normally done. The mirror is an alternative means of determining the Doppler spectrum of point particles. From the exact result, an approximation method is derived that is of use to radar engineers. Extending these results to other commonly used radar waveforms is considered.<>
{"title":"The Doppler spectrum for accelerating objects","authors":"John E. Gray","doi":"10.1109/RADAR.1990.201196","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201196","url":null,"abstract":"The formalism for computing the Doppler spectrum for perfectly reflecting mirrors undergoing various types of accelerations is reviewed. This method is an amplification of work done by D. Censor and J. Cooper for one-dimensional waves. For sinusoidal waves, the formalism provides a computationally easy algorithm that enables determination of the Doppler spectrum. This method is exact and does not ignore the effects of motion on the amplitude, as is normally done. The mirror is an alternative means of determining the Doppler spectrum of point particles. From the exact result, an approximation method is derived that is of use to radar engineers. Extending these results to other commonly used radar waveforms is considered.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"33 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":"122698369","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.1990.201139
J. Moreira
The performance of the reflectivity displacement method is reported. The reflectivity displacement method extracts all the necessary motions of the aircraft from the radar backscatter signal using a new radar configuration and new methods for evaluating the azimuth spectra of the radar signal. Hence, an inertial navigation system is unnecessary for many applications. An error analysis of this method is carried out, and a comparison of two processed images with and without motion compensation is shown, proving the estimated performance.<>
{"title":"Estimating the residual error of the reflectivity displacement method for aircraft motion error extraction from SAR raw data","authors":"J. Moreira","doi":"10.1109/RADAR.1990.201139","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201139","url":null,"abstract":"The performance of the reflectivity displacement method is reported. The reflectivity displacement method extracts all the necessary motions of the aircraft from the radar backscatter signal using a new radar configuration and new methods for evaluating the azimuth spectra of the radar signal. Hence, an inertial navigation system is unnecessary for many applications. An error analysis of this method is carried out, and a comparison of two processed images with and without motion compensation is shown, proving the estimated performance.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"80 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":"122834777","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.1990.201092
Qiangfu Zhao, Zhong Wang, Youan Ke
A discrete model for radar imaging is developed, and, based on this model, the maximum entropy algorithm is adapted to radar imaging. Although such iterative algorithms are usually time-consuming, it is shown that, if the algorithms are appropriately simplified, it is possible to realize them even in real time. The efficiency of iterative algorithms is shown through computer simulations.<>
{"title":"Radar imaging based on iterative algorithms","authors":"Qiangfu Zhao, Zhong Wang, Youan Ke","doi":"10.1109/RADAR.1990.201092","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201092","url":null,"abstract":"A discrete model for radar imaging is developed, and, based on this model, the maximum entropy algorithm is adapted to radar imaging. Although such iterative algorithms are usually time-consuming, it is shown that, if the algorithms are appropriately simplified, it is possible to realize them even in real time. The efficiency of iterative algorithms is shown through computer simulations.<<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":"129063247","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.1990.201107
N. Levanon
The performances of the classical video integrator and the well-known binary integrator (which can also be called an order statistics integrator) are compared with that of a new integrator, called the censored video integrator (CVI), for a Swerling II target in Gaussian noise. CVI performs sorting, censoring, and nonuniform weighted averaging. It is shown that for a Swerling II target, the added loss of CVI is always lower than the added loss of the corresponding binary integrator. CVI is also less susceptible to strong interferences.<>
{"title":"Censored video integration in radar detection","authors":"N. Levanon","doi":"10.1109/RADAR.1990.201107","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201107","url":null,"abstract":"The performances of the classical video integrator and the well-known binary integrator (which can also be called an order statistics integrator) are compared with that of a new integrator, called the censored video integrator (CVI), for a Swerling II target in Gaussian noise. CVI performs sorting, censoring, and nonuniform weighted averaging. It is shown that for a Swerling II target, the added loss of CVI is always lower than the added loss of the corresponding binary integrator. CVI is also less susceptible to strong interferences.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"35 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":"127872838","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.1990.201161
J. P. Reilly
Limitations on achievable clutter rejection due to ambiguous range clutter are described. The profile of clutter power versus range is shown to limit achievable clutter rejection. Ambiguous range effects are discussed in the context of sea clutter, using a model that includes propagation conditions, and rain clutter. Limitations in moving target indication systems are illustrated for sea clutter, where propagation is subject to evaporation ducts. Benefits of fill pulses are illustrated for rain and sea clutter.<>
{"title":"Clutter rejection limitations from ambiguous range clutter","authors":"J. P. Reilly","doi":"10.1109/RADAR.1990.201161","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201161","url":null,"abstract":"Limitations on achievable clutter rejection due to ambiguous range clutter are described. The profile of clutter power versus range is shown to limit achievable clutter rejection. Ambiguous range effects are discussed in the context of sea clutter, using a model that includes propagation conditions, and rain clutter. Limitations in moving target indication systems are illustrated for sea clutter, where propagation is subject to evaporation ducts. Benefits of fill pulses are illustrated for rain and sea clutter.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"16 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121016544","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.1990.201203
B. Bergkvist, Bert-Eric Tullsson
Track while scan radar accuracy has been studied for targets of Swerling 1 and 2 types with angular widths. The investigations have led to an improved insight into effects of field intensity variation over the target during beam scanning. This experience, in combination with knowledge of monopulse techniques, has suggested methods to improve track while scan radar performance with respect to both accuracy and resolution. Methods have been designed and evaluated theoretically and by practical measurements of real targets. The results indicate significant possible improvements in accuracy with targets exhibiting rapid fading and glint, as well as for jammed scenarios. These results also show excellent performance against closely spaced targets in both detection of multiple target simulations and accurate estimation of the angular positions for target separations as close as 0.5-0.7 beamwidths.<>
{"title":"Track while scan monopulse-a technique for improving angular accuracy and resolution","authors":"B. Bergkvist, Bert-Eric Tullsson","doi":"10.1109/RADAR.1990.201203","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201203","url":null,"abstract":"Track while scan radar accuracy has been studied for targets of Swerling 1 and 2 types with angular widths. The investigations have led to an improved insight into effects of field intensity variation over the target during beam scanning. This experience, in combination with knowledge of monopulse techniques, has suggested methods to improve track while scan radar performance with respect to both accuracy and resolution. Methods have been designed and evaluated theoretically and by practical measurements of real targets. The results indicate significant possible improvements in accuracy with targets exhibiting rapid fading and glint, as well as for jammed scenarios. These results also show excellent performance against closely spaced targets in both detection of multiple target simulations and accurate estimation of the angular positions for target separations as close as 0.5-0.7 beamwidths.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"41 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":"116426172","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.1990.201201
W. Gilson
A methodology for relating the resources consumed by tracking a maneuvering target to the track accuracy achieved is described. This methodology accounts for beam shape loss, missed detections, and, in the case of a fire-control radar, reacquisition of the target when it has moved outside the beam. Normalized computational results for the minimum radar power required as a function of the track accuracy are presented, along with the optimal revisit frequencies and the signal-to-noise ratios.<>
{"title":"Minimum power requirements of tracking","authors":"W. Gilson","doi":"10.1109/RADAR.1990.201201","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201201","url":null,"abstract":"A methodology for relating the resources consumed by tracking a maneuvering target to the track accuracy achieved is described. This methodology accounts for beam shape loss, missed detections, and, in the case of a fire-control radar, reacquisition of the target when it has moved outside the beam. Normalized computational results for the minimum radar power required as a function of the track accuracy are presented, along with the optimal revisit frequencies and the signal-to-noise ratios.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"40 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":"123773784","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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