This paper addresses the problem of developing signal processing, moving target detection, and image formation algorithms, for an airborne array radar system, called Multi-Channel Airborne Radar Measurement (MCARM), developed by the Air Force Research Laboratory at Rome, New York. Our approach is based on interpreting the MCARM data via a multichannel SAR system. SAR imaging and blind calibration of a dual along-track SAR-MTI system are then used for the MCARM data.
{"title":"SAR-MTI processing of multi-channel airborne radar measurement (MCARM) data","authors":"M. Soumekh, B. Himed","doi":"10.1109/NRC.2002.999687","DOIUrl":"https://doi.org/10.1109/NRC.2002.999687","url":null,"abstract":"This paper addresses the problem of developing signal processing, moving target detection, and image formation algorithms, for an airborne array radar system, called Multi-Channel Airborne Radar Measurement (MCARM), developed by the Air Force Research Laboratory at Rome, New York. Our approach is based on interpreting the MCARM data via a multichannel SAR system. SAR imaging and blind calibration of a dual along-track SAR-MTI system are then used for the MCARM data.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128114332","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}
Based upon the central limit theorem, random clutter returns are commonly modeled as Gaussian. Nevertheless, many situations arise in practice where the data are clearly non-Gaussian, as is seen with "spiky" radar clutter. Spherically invariant random vectors (SIRVs) are especially attractive for modeling correlated non-Gaussian clutter. This paper discusses the computer simulation of SIRVs for Monte Carlo purposes using the rejection method. A key requirement of the rejection method is the ability to find a tight bound of the probability density function, from which random samples can be readily generated. An automated technique for generating this bound for the SIRV probability density function is presented.
{"title":"Generation of rejection method bounds for spherically invariant random vectors","authors":"A. D. Keckler, D. Weiner","doi":"10.1109/NRC.2002.999690","DOIUrl":"https://doi.org/10.1109/NRC.2002.999690","url":null,"abstract":"Based upon the central limit theorem, random clutter returns are commonly modeled as Gaussian. Nevertheless, many situations arise in practice where the data are clearly non-Gaussian, as is seen with \"spiky\" radar clutter. Spherically invariant random vectors (SIRVs) are especially attractive for modeling correlated non-Gaussian clutter. This paper discusses the computer simulation of SIRVs for Monte Carlo purposes using the rejection method. A key requirement of the rejection method is the ability to find a tight bound of the probability density function, from which random samples can be readily generated. An automated technique for generating this bound for the SIRV probability density function is presented.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133273296","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}
In order to produce controllable deep zeroes in antenna patterns for signals with bandwidths comparable to antenna dimensions, beamforming by "true time delay" (TTD) has to be used. Normally, TTD is hard to achieve electrically for a big antenna array because it is hard to produce long delays without reducing the system bandwidth. The motivation. for this investigation is to see if, by combining digital and analog delays, a method can be found to produce long delays digitally and short delays with analog electric circuits without reducing system bandwidth. For all test cases, we found that a "fractional sample delay" (FSD) filter gives an improvement when taking the difference between two receiver channels in an antenna array. Our conclusion is therefore that this design can be used to improve the wideband performance for controllable zeroes in antenna patterns without using higher sample rates than normal; if the signal can be handled digitally, so can the time shifting. Depending on the physical dimensions of the sub antennas compared to the signal bandwidth, TTD may not even have to be used.
{"title":"An efficient beamforming method using a combination of analog true time and digital delay","authors":"L. Morgan, H. Andersson","doi":"10.1109/NRC.2002.999729","DOIUrl":"https://doi.org/10.1109/NRC.2002.999729","url":null,"abstract":"In order to produce controllable deep zeroes in antenna patterns for signals with bandwidths comparable to antenna dimensions, beamforming by \"true time delay\" (TTD) has to be used. Normally, TTD is hard to achieve electrically for a big antenna array because it is hard to produce long delays without reducing the system bandwidth. The motivation. for this investigation is to see if, by combining digital and analog delays, a method can be found to produce long delays digitally and short delays with analog electric circuits without reducing system bandwidth. For all test cases, we found that a \"fractional sample delay\" (FSD) filter gives an improvement when taking the difference between two receiver channels in an antenna array. Our conclusion is therefore that this design can be used to improve the wideband performance for controllable zeroes in antenna patterns without using higher sample rates than normal; if the signal can be handled digitally, so can the time shifting. Depending on the physical dimensions of the sub antennas compared to the signal bandwidth, TTD may not even have to be used.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131006639","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 new chaff cloud model is described which is based on fundamental principles with modifications based on laboratory observations. Excellent approximations to the exact physical model have been developed which can rapidly predict the chaff fiber density and orientation as a function of location, time and fiber characteristics. Using this information, the time varying RCS density is determined for any frequency and polarization anywhere within the chaff cloud. The results are consistent with full scale observations and the computational speed allows the model to be integrated into existing real time radar simulations.
{"title":"The dynamics and radar cross section density of chaff clouds","authors":"S. Marcus","doi":"10.1109/NRC.2002.999732","DOIUrl":"https://doi.org/10.1109/NRC.2002.999732","url":null,"abstract":"A new chaff cloud model is described which is based on fundamental principles with modifications based on laboratory observations. Excellent approximations to the exact physical model have been developed which can rapidly predict the chaff fiber density and orientation as a function of location, time and fiber characteristics. Using this information, the time varying RCS density is determined for any frequency and polarization anywhere within the chaff cloud. The results are consistent with full scale observations and the computational speed allows the model to be integrated into existing real time radar simulations.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131124204","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 stepped-frequency waveform is used to obtain large effective bandwidth for high range resolution by transmitting the pulses with sequentially changing carrier frequency, so that is reduces the requirements on instantaneous bandwidth and receiver. However, this waveform is very sensitive to the radial velocity between radar and targets, which results in the loss of range resolution and SNR. This paper combines the stepped-frequency waveform with synthetic aperture radar (SAR) in order to achieve the high resolution image in two dimensions. Furthermore, the consideration of waveform design is discussed, and the simulation results, which validate the method, are shown.
{"title":"Stepped-frequency waveform design for SAR imaging and radial velocity compensation","authors":"Liu Haiying, Y. Ruliang","doi":"10.1109/NRC.2002.999766","DOIUrl":"https://doi.org/10.1109/NRC.2002.999766","url":null,"abstract":"The stepped-frequency waveform is used to obtain large effective bandwidth for high range resolution by transmitting the pulses with sequentially changing carrier frequency, so that is reduces the requirements on instantaneous bandwidth and receiver. However, this waveform is very sensitive to the radial velocity between radar and targets, which results in the loss of range resolution and SNR. This paper combines the stepped-frequency waveform with synthetic aperture radar (SAR) in order to achieve the high resolution image in two dimensions. Furthermore, the consideration of waveform design is discussed, and the simulation results, which validate the method, are shown.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"170 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115006745","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. McMillan, R. Smith, M. Shipman, E. J. Holder, J. C. Kerce, J. Williams
Atmospheric turbulence has been shown to have measurable effects on the angle-of-arrival (AOA) of radar beams, but these effects are on the order of a few microradians, which is a negligible level for most applications. In this paper, we present a theory describing this phenomenon and compare this theory to one-way measurements made over a 3.5 km path and two-way measurements made over a 25 km path using an X-band interferometric radar.
{"title":"Angle-of-arrival of a radar beam in atmospheric turbulence","authors":"R. McMillan, R. Smith, M. Shipman, E. J. Holder, J. C. Kerce, J. Williams","doi":"10.1109/NRC.2002.999728","DOIUrl":"https://doi.org/10.1109/NRC.2002.999728","url":null,"abstract":"Atmospheric turbulence has been shown to have measurable effects on the angle-of-arrival (AOA) of radar beams, but these effects are on the order of a few microradians, which is a negligible level for most applications. In this paper, we present a theory describing this phenomenon and compare this theory to one-way measurements made over a 3.5 km path and two-way measurements made over a 25 km path using an X-band interferometric radar.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115409211","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}
Radars commonly use wide bandwidth pulses to attain high range resolution. However, when such wideband pulses are unavailable (or otherwise undesirable), high range resolution can still be achieved by coherently combining a sequence of narrowband pulses spanning the desired bandwidth. Collectively, such narrowband pulse sequences are said to compose a "synthetic wideband waveform" (specific variants are also known by the names "stepped frequency waveform", "frequency jump burst" and "frequency jump train"). Prior publications and reports have examined synthetic wideband waveforms that distribute energy uniformly over the frequency band. Such waveforms require heavy spectral weighting, highly overlapped pulses and/or nonperiodic pulses to control the range sidelobes and grating lobes; unfortunately, undesirable attributes are associated with each of these. We formulate synthetic waveforms that distribute energy nonuniformly over the desired frequency band. These new waveforms are shown to offer improved performance (i.e., lower range sidelobes, higher gain, higher range resolution and/or reduced grating lobes) when compared with traditional approaches.
{"title":"Nonlinear synthetic wideband waveforms","authors":"D. Rabideau","doi":"10.1109/NRC.2002.999721","DOIUrl":"https://doi.org/10.1109/NRC.2002.999721","url":null,"abstract":"Radars commonly use wide bandwidth pulses to attain high range resolution. However, when such wideband pulses are unavailable (or otherwise undesirable), high range resolution can still be achieved by coherently combining a sequence of narrowband pulses spanning the desired bandwidth. Collectively, such narrowband pulse sequences are said to compose a \"synthetic wideband waveform\" (specific variants are also known by the names \"stepped frequency waveform\", \"frequency jump burst\" and \"frequency jump train\"). Prior publications and reports have examined synthetic wideband waveforms that distribute energy uniformly over the frequency band. Such waveforms require heavy spectral weighting, highly overlapped pulses and/or nonperiodic pulses to control the range sidelobes and grating lobes; unfortunately, undesirable attributes are associated with each of these. We formulate synthetic waveforms that distribute energy nonuniformly over the desired frequency band. These new waveforms are shown to offer improved performance (i.e., lower range sidelobes, higher gain, higher range resolution and/or reduced grating lobes) when compared with traditional approaches.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115762421","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}
We assess the frequency estimation accuracy of the recently introduced reduced rank autoregressive linear predictor called reduced order correlation kernel estimation technique (ROCKET). We compare the frequency estimation performance of ROCKET to both the conventional full rank autoregressive (FR-AR) method and the theoretical limit imposed by the Cramer-Rao bound (CRB). The analysis includes estimation accuracy as a function of signal-to-noise ratio (SNR), data length, and subspace rank. Simulations reveal that ROCKET can approach the CRB for a much greater range of SNR levels and for shorter data sequences than FR-AR. Perhaps more importantly, ROCKET's performance is shown to be very robust to subspace rank selection. This means that a priori knowledge of the upperbound of the number of frequencies present is not crucial to this reduced rank algorithm. Finally, it is shown that a small frequency estimation bias appears when the subspace rank is well below the signal rank.
{"title":"Frequency estimation accuracy of ROCKET","authors":"H. Witzgall, W. Ogle, J. S. Goldstein","doi":"10.1109/NRC.2002.999685","DOIUrl":"https://doi.org/10.1109/NRC.2002.999685","url":null,"abstract":"We assess the frequency estimation accuracy of the recently introduced reduced rank autoregressive linear predictor called reduced order correlation kernel estimation technique (ROCKET). We compare the frequency estimation performance of ROCKET to both the conventional full rank autoregressive (FR-AR) method and the theoretical limit imposed by the Cramer-Rao bound (CRB). The analysis includes estimation accuracy as a function of signal-to-noise ratio (SNR), data length, and subspace rank. Simulations reveal that ROCKET can approach the CRB for a much greater range of SNR levels and for shorter data sequences than FR-AR. Perhaps more importantly, ROCKET's performance is shown to be very robust to subspace rank selection. This means that a priori knowledge of the upperbound of the number of frequencies present is not crucial to this reduced rank algorithm. Finally, it is shown that a small frequency estimation bias appears when the subspace rank is well below the signal rank.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116228284","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}
P. Brown, J. Casey, J. Mulvaney, T. Hawkey, M. Kempkes, M. Gaudreau
The operational life of high power radar transmitters that employ microwave vacuum electron device (VEDs) can be extended using high voltage, solid-state modulators and power supplies. Solid-state modulators and power supplies, whether integrated, or stand-alone, can benefit both retrofits and new designs. In this paper, modern solid-state modulator topologies are presented along with the conventional topologies that they replace. Several specific fielded radar transmitters that have been, or could be, retrofitted with "appropriate technology" are identified.
{"title":"Improvements in radar transmitter performance and reliability using high-voltage solid-state modulators and power supplies","authors":"P. Brown, J. Casey, J. Mulvaney, T. Hawkey, M. Kempkes, M. Gaudreau","doi":"10.1109/NRC.2002.999705","DOIUrl":"https://doi.org/10.1109/NRC.2002.999705","url":null,"abstract":"The operational life of high power radar transmitters that employ microwave vacuum electron device (VEDs) can be extended using high voltage, solid-state modulators and power supplies. Solid-state modulators and power supplies, whether integrated, or stand-alone, can benefit both retrofits and new designs. In this paper, modern solid-state modulator topologies are presented along with the conventional topologies that they replace. Several specific fielded radar transmitters that have been, or could be, retrofitted with \"appropriate technology\" are identified.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122807081","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}
Conventional phased array radars traditionally use digital filters that are adaptive in frequency on receive and use a fixed transmit pattern to illuminate their targets. Unfortunately such an approach does not take into consideration the spatial diversity of targets and interference sources that the phased array observes as it is electronically pointed throughout its search area. We propose a methodology that uses a wavelet filter bank to selectively transmit and receive radiation that is directionally dependent on the phased array's pointing direction. Such an approach allows us to illuminate with and receive radiation from targets in a way that is frequency selective depending on the pointing direction of the array and also more efficiently detect targets due to the compact spectral model produced by the wavelet filter bank.
{"title":"Using a wavelet basis for a spectrally tunable phased array","authors":"R. Bonneau, M. Wicks","doi":"10.1109/NRC.2002.999704","DOIUrl":"https://doi.org/10.1109/NRC.2002.999704","url":null,"abstract":"Conventional phased array radars traditionally use digital filters that are adaptive in frequency on receive and use a fixed transmit pattern to illuminate their targets. Unfortunately such an approach does not take into consideration the spatial diversity of targets and interference sources that the phased array observes as it is electronically pointed throughout its search area. We propose a methodology that uses a wavelet filter bank to selectively transmit and receive radiation that is directionally dependent on the phased array's pointing direction. Such an approach allows us to illuminate with and receive radiation from targets in a way that is frequency selective depending on the pointing direction of the array and also more efficiently detect targets due to the compact spectral model produced by the wavelet filter bank.","PeriodicalId":448055,"journal":{"name":"Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126006324","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：