Pub Date : 1990-05-07DOI: 10.1109/RADAR.1990.201158
M. Tuszynski, A. Wojtkiewicz, W. Klembowski
A low-cost, simple adaptive moving target indication (MTI) system for weather and ground clutter rejection is described. The system will be retrofitted into a number of existing staggered PRF radars in order to improve their detection capabilities. The system consists of an adaptive digital MTI filter with complex coefficients, weather clutter map, and clutter parameter estimation unit. The possibility of increasing weather clutter attenuation by the use of a digital MTI filter with complex coefficients has been verified experimentally in the L-band PSR ATC radar AVIA-C, and preliminary experimental results are presented.<>
{"title":"Bimodal clutter MTI filter for staggered PRF radars","authors":"M. Tuszynski, A. Wojtkiewicz, W. Klembowski","doi":"10.1109/RADAR.1990.201158","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201158","url":null,"abstract":"A low-cost, simple adaptive moving target indication (MTI) system for weather and ground clutter rejection is described. The system will be retrofitted into a number of existing staggered PRF radars in order to improve their detection capabilities. The system consists of an adaptive digital MTI filter with complex coefficients, weather clutter map, and clutter parameter estimation unit. The possibility of increasing weather clutter attenuation by the use of a digital MTI filter with complex coefficients has been verified experimentally in the L-band PSR ATC radar AVIA-C, and preliminary experimental results are presented.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"98 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":"116435454","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.1990.201098
Y.-N. Chung
An algorithm for solving multiple maneuvering target tracking problems using a global modeling approach is presented. A simulation structure for three-dimensional tracking situations is given. Once radar measurement data are received, the a posteriori probability which is referred to as a weighting factor is calculated using an adaptive filter for each hypothesis. Computer simulation results indicate that the multiple maneuvering targets can be tracked successfully.<>
{"title":"Application of the unifying approach to multiple target tracking","authors":"Y.-N. Chung","doi":"10.1109/RADAR.1990.201098","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201098","url":null,"abstract":"An algorithm for solving multiple maneuvering target tracking problems using a global modeling approach is presented. A simulation structure for three-dimensional tracking situations is given. Once radar measurement data are received, the a posteriori probability which is referred to as a weighting factor is calculated using an adaptive filter for each hypothesis. Computer simulation results indicate that the multiple maneuvering targets can be tracked successfully.<<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":"123414923","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.1990.201163
N. Franzén
Since artillery shells and birds have similar radar cross sections, a clutter map is introduced to prevent the overloading of an artillery locating radar by bird echoes. A simple mathematical model for the function of the clutter map has been developed. The model is based on a stochastic description of the birds, including the distribution of cross sections, velocities, and bird densities. In parallel with the mathematical analysis of the clutter map, Monte Carlo simulation has been performed to verify the properties of the map. Calculations indicate that efficiency of the radar is increased dramatically when the clutter map is used. Without the map, at very low bird densities (such as 0.1 to 0.2 birds/km/sup 2/) the system is overloaded, wasting all its time on birds. When the map is introduced the system manages to handle ten times more birds before it enters the overload regime.<>
{"title":"The use of a clutter map in the artillery locating radar ARTHUR","authors":"N. Franzén","doi":"10.1109/RADAR.1990.201163","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201163","url":null,"abstract":"Since artillery shells and birds have similar radar cross sections, a clutter map is introduced to prevent the overloading of an artillery locating radar by bird echoes. A simple mathematical model for the function of the clutter map has been developed. The model is based on a stochastic description of the birds, including the distribution of cross sections, velocities, and bird densities. In parallel with the mathematical analysis of the clutter map, Monte Carlo simulation has been performed to verify the properties of the map. Calculations indicate that efficiency of the radar is increased dramatically when the clutter map is used. Without the map, at very low bird densities (such as 0.1 to 0.2 birds/km/sup 2/) the system is overloaded, wasting all its time on birds. When the map is introduced the system manages to handle ten times more birds before it enters the overload regime.<<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":"121927983","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.1990.201205
S. Rogers
The effect of glint errors on target tracking accuracies is studied by various analytical means. The glint error is modeled as a first-order Markov process, characterized by a correlation time ( tau ) and a position error variance. The target motion is described by one of two dynamic models: the exponentially correlated velocity model and the exponentially correlated acceleration model. For both models, the steady-state variance of the estimated target velocity exhibits resonant behavior whenever the time-constant for target maneuvers is close to tau . The analysis is simplified through the use of some mathematical tricks, which may themselves be of interest to Kalman filter specialists.<>
{"title":"Effect of glint errors on steady-state tracking accuracies of maneuvering targets","authors":"S. Rogers","doi":"10.1109/RADAR.1990.201205","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201205","url":null,"abstract":"The effect of glint errors on target tracking accuracies is studied by various analytical means. The glint error is modeled as a first-order Markov process, characterized by a correlation time ( tau ) and a position error variance. The target motion is described by one of two dynamic models: the exponentially correlated velocity model and the exponentially correlated acceleration model. For both models, the steady-state variance of the estimated target velocity exhibits resonant behavior whenever the time-constant for target maneuvers is close to tau . The analysis is simplified through the use of some mathematical tricks, which may themselves be of interest to Kalman filter specialists.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"75 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":"127378593","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.1990.201095
J. Watkins, S. Uysal
An experimental investigation of broadband microstrip antennas on a PTFE substrate with permittivity epsilon /sub r/=2.1 and thickness h=1.6 mm is presented. A 17% bandwidth improvement is achieved by modifying the feed on the substrate with coaxial-fed disk antennas. Experiments carried out on circularly shaped modified patches showed a further bandwidth improvement of 80% over conventional microstrip patches. This method of bandwidth improvement is based on the fact that the impedance match is the limiting factor to the bandwidth for this class of antennas.<>
{"title":"Experimental investigation of broad-band microstrip antennas","authors":"J. Watkins, S. Uysal","doi":"10.1109/RADAR.1990.201095","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201095","url":null,"abstract":"An experimental investigation of broadband microstrip antennas on a PTFE substrate with permittivity epsilon /sub r/=2.1 and thickness h=1.6 mm is presented. A 17% bandwidth improvement is achieved by modifying the feed on the substrate with coaxial-fed disk antennas. Experiments carried out on circularly shaped modified patches showed a further bandwidth improvement of 80% over conventional microstrip patches. This method of bandwidth improvement is based on the fact that the impedance match is the limiting factor to the bandwidth for this class of antennas.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"68 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":"126315114","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.1990.201141
W. M. Kemp, N. Martin
Part of Australia's contribution to the European Space Agency's ERS-1 synthetic aperture radar experiment is the development of an active transponder to assist in the calibration of radar images. The architecture and experimental evaluation of a C-band zero-delay transponder are described in detail. The self-calibration loop of the system has been shown to provide and maintain 60 dB of active gain to an accuracy of 0.1 dB.<>
{"title":"A synthetic aperture radar calibration transponder at C-band","authors":"W. M. Kemp, N. Martin","doi":"10.1109/RADAR.1990.201141","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201141","url":null,"abstract":"Part of Australia's contribution to the European Space Agency's ERS-1 synthetic aperture radar experiment is the development of an active transponder to assist in the calibration of radar images. The architecture and experimental evaluation of a C-band zero-delay transponder are described in detail. The self-calibration loop of the system has been shown to provide and maintain 60 dB of active gain to an accuracy of 0.1 dB.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"14 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":"115030110","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.1990.201180
A. Theil
When adaptive nullsteering is applied to attenuate interfering signals which are received via the main lobe, two limitations manifest themselves: the side lobe level increases and the peak of the main beam shifts away from the desired look direction (squinted main beam). A two-step method which maintains angular accuracy even under main lobe interference conditions is described. In the first step, adaptive nullsteering is performed to enable the detection of targets; the distortion of the main beam is allowed. In the second step, high-resolution angle estimation techniques are used to obtain the angles of the target and the interference sources. The procedure requires prior knowledge of the number of interfering signals; an interference map can be used to provide this information.<>
{"title":"On combining adaptive nullsteering with high resolution angle estimation under main lobe interference conditions","authors":"A. Theil","doi":"10.1109/RADAR.1990.201180","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201180","url":null,"abstract":"When adaptive nullsteering is applied to attenuate interfering signals which are received via the main lobe, two limitations manifest themselves: the side lobe level increases and the peak of the main beam shifts away from the desired look direction (squinted main beam). A two-step method which maintains angular accuracy even under main lobe interference conditions is described. In the first step, adaptive nullsteering is performed to enable the detection of targets; the distortion of the main beam is allowed. In the second step, high-resolution angle estimation techniques are used to obtain the angles of the target and the interference sources. The procedure requires prior knowledge of the number of interfering signals; an interference map can be used to provide this information.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"30 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":"125520530","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.1990.201188
R. Klemm, J. Ender
The performance of adaptive moving target indication (MTI) filters for use on airborne radar platforms is addressed. Clutter returns received by a moving radar exhibit a Doppler shift which depends on the platform velocity, on the cosine of the angle between the flight axis, and the position of the individual scatterer. Therefore, the platform motion causes clutter echoes to be Doppler broadband, with the bandlimits determined by the platform speed. Efficient clutter suppression requires platform motion compensation or, more general, two-dimensional MTI filters which operate in time and space. In the spatial dimension echo signals may be subject to decorrelation due to the system bandwidth. Such effects are discussed. The results are of particular importance for high-resolution airborne search radar, including real and synthetic aperture applications.<>
{"title":"New aspects of airborne MTI","authors":"R. Klemm, J. Ender","doi":"10.1109/RADAR.1990.201188","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201188","url":null,"abstract":"The performance of adaptive moving target indication (MTI) filters for use on airborne radar platforms is addressed. Clutter returns received by a moving radar exhibit a Doppler shift which depends on the platform velocity, on the cosine of the angle between the flight axis, and the position of the individual scatterer. Therefore, the platform motion causes clutter echoes to be Doppler broadband, with the bandlimits determined by the platform speed. Efficient clutter suppression requires platform motion compensation or, more general, two-dimensional MTI filters which operate in time and space. In the spatial dimension echo signals may be subject to decorrelation due to the system bandwidth. Such effects are discussed. The results are of particular importance for high-resolution airborne search radar, including real and synthetic aperture applications.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"12 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":"125772364","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.1990.201156
K.J. Hammerle
Displaced phase center antenna (DPCA) is a technique for improving clutter rejection in airborne radars which use Doppler processing. Andrews (1972) evaluated DPCA in systems that incorporate delay line cancelers. This study extends the earlier work to include coherent integration. An analytical structure is established for accommodating an arbitrary number (n) of cancelers and an arbitrary number (N) of pulses integrated. The measure of performance is the standard improvement factor I. Quantitative results are presented for various combinations of the important parameters: n, N, platform speed, and clutter spectral width. In addition, convenient compact expressions for approximating I are developed.<>
{"title":"Cascaded MTI and coherent integration techniques with motion compensation","authors":"K.J. Hammerle","doi":"10.1109/RADAR.1990.201156","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201156","url":null,"abstract":"Displaced phase center antenna (DPCA) is a technique for improving clutter rejection in airborne radars which use Doppler processing. Andrews (1972) evaluated DPCA in systems that incorporate delay line cancelers. This study extends the earlier work to include coherent integration. An analytical structure is established for accommodating an arbitrary number (n) of cancelers and an arbitrary number (N) of pulses integrated. The measure of performance is the standard improvement factor I. Quantitative results are presented for various combinations of the important parameters: n, N, platform speed, and clutter spectral width. In addition, convenient compact expressions for approximating I are developed.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"19 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":"125778662","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.1990.201138
K. Ward, R. Tough, B. Haywood
A radar imaging theory for synthetic aperture radar (SAR), inverse SAR (ISAR), and hybrid SAR-ISAR is developed from the Fourier transform of k space samples. The rotations due to the radar and the object are combined in the hybrid SAR-ISAR case, and a small angle approximation is derived. The analysis presented is limited to small angles of rotation and constant angular velocities; however, extensions to this have been derived and are briefly discussed. Of particular interest are the expected image orientation and the effect of inaccurate knowledge of motion parameters on image quality. Both of these are considered in theory and then demonstrated in simulations based on multisource models of ship radar cross section.<>
{"title":"Hybrid SAR-ISAR imaging of ships","authors":"K. Ward, R. Tough, B. Haywood","doi":"10.1109/RADAR.1990.201138","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201138","url":null,"abstract":"A radar imaging theory for synthetic aperture radar (SAR), inverse SAR (ISAR), and hybrid SAR-ISAR is developed from the Fourier transform of k space samples. The rotations due to the radar and the object are combined in the hybrid SAR-ISAR case, and a small angle approximation is derived. The analysis presented is limited to small angles of rotation and constant angular velocities; however, extensions to this have been derived and are briefly discussed. Of particular interest are the expected image orientation and the effect of inaccurate knowledge of motion parameters on image quality. Both of these are considered in theory and then demonstrated in simulations based on multisource models of ship radar cross section.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"2016 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":"128887793","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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