Pub Date : 2014-05-19DOI: 10.1109/RADAR.2014.6875693
S. Gogineni, M. Rangaswamy, B. Rigling, A. Nehorai
Mobile communications systems are being increasingly deployed and the favorable ambiguity function properties of these signals make them useful for passive bistatic radar applications. Further, simultaneously using multiple illuminators of opportunity in a multistatic configuration will enhance the radar performance, providing spatial diversity and increased resolution. We compute modified Cramer-Rao lower bounds (MCRLB) for the target parameter estimation error using universal mobile telecommunications system (UMTS) signals as illuminators of opportunity for passive multistatic radar systems.
{"title":"Cramer-Rao bound analysis for passive multistatic radar using UMTS signals","authors":"S. Gogineni, M. Rangaswamy, B. Rigling, A. Nehorai","doi":"10.1109/RADAR.2014.6875693","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875693","url":null,"abstract":"Mobile communications systems are being increasingly deployed and the favorable ambiguity function properties of these signals make them useful for passive bistatic radar applications. Further, simultaneously using multiple illuminators of opportunity in a multistatic configuration will enhance the radar performance, providing spatial diversity and increased resolution. We compute modified Cramer-Rao lower bounds (MCRLB) for the target parameter estimation error using universal mobile telecommunications system (UMTS) signals as illuminators of opportunity for passive multistatic radar systems.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131892243","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875793
Yue Ai, Wei Yi, G. Cui, L. Kong
This paper addresses the multi-target localization problem for noncoherent multiple-input multiple-output (MIMO) radar with widely separated antennas. To this end, we first adopt a high-dimensional parameter vector, which is the concatenation of the parameters to be estimated for individual targets, and then propose a novel multi-target localization algorithm by estimating the high-dimensional parameter vector based on maximum-likelihood estimation (MLE). However, this solution is usually computationally intractable for most realistic problems as it is involved with a high-dimensional joint maximization. Therefore we also propose a suboptimum algorithm which allows trading better localization accuracy for a much lower implementation complexity. Numerical examples are provided to assess and compare the performances of the proposed multi-target localization algorithms.
{"title":"Multi-target localization for noncoherent MIMO radar with widely separated antennas","authors":"Yue Ai, Wei Yi, G. Cui, L. Kong","doi":"10.1109/RADAR.2014.6875793","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875793","url":null,"abstract":"This paper addresses the multi-target localization problem for noncoherent multiple-input multiple-output (MIMO) radar with widely separated antennas. To this end, we first adopt a high-dimensional parameter vector, which is the concatenation of the parameters to be estimated for individual targets, and then propose a novel multi-target localization algorithm by estimating the high-dimensional parameter vector based on maximum-likelihood estimation (MLE). However, this solution is usually computationally intractable for most realistic problems as it is involved with a high-dimensional joint maximization. Therefore we also propose a suboptimum algorithm which allows trading better localization accuracy for a much lower implementation complexity. Numerical examples are provided to assess and compare the performances of the proposed multi-target localization algorithms.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131902267","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875669
R. Raj
We apply our recently developed concept of mutual exclusivity [1] in the context of discriminative coding, to the problem of learning dictionary for representing signals drawn from N classes in a way that optimizes their discriminability. We first briefly review our mutual-exclusivity concept and then deploy it a simple discriminative dictionary learning algorithm that directly generalizes the well-known KSVD algorithm which is addressed for the traditional problem of signal coding. We demonstrate performance improvements over traditional KSVD based feature extraction schemes and conclude by describing avenues for future research.
{"title":"Discriminative dictionary learning via mutual exclusion","authors":"R. Raj","doi":"10.1109/RADAR.2014.6875669","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875669","url":null,"abstract":"We apply our recently developed concept of mutual exclusivity [1] in the context of discriminative coding, to the problem of learning dictionary for representing signals drawn from N classes in a way that optimizes their discriminability. We first briefly review our mutual-exclusivity concept and then deploy it a simple discriminative dictionary learning algorithm that directly generalizes the well-known KSVD algorithm which is addressed for the traditional problem of signal coding. We demonstrate performance improvements over traditional KSVD based feature extraction schemes and conclude by describing avenues for future research.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134112085","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875703
S. Halai, P. Brennan, D. Patrick, I. Weller
Active target based FMCW radar location systems have niche short range applications which include maritime navigation with the berthing of ships and other vessels and avoiding obstacles such as oil rigs. For these types of systems the target return decays at a greater rate than the background clutter, thus making target detection difficult. In this paper, a technique is explored, based on frequency shifting the radar echo within the target, which serves to translate the position of the of the received target return to a higher frequency where the clutter is greatly reduced. It is shown, by means of a suitable design and simulation, that this approach may readily be used to achieve a much greater operating range in these types of location systems.
{"title":"Frequency shifted active target for use in FMCW radar systems","authors":"S. Halai, P. Brennan, D. Patrick, I. Weller","doi":"10.1109/RADAR.2014.6875703","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875703","url":null,"abstract":"Active target based FMCW radar location systems have niche short range applications which include maritime navigation with the berthing of ships and other vessels and avoiding obstacles such as oil rigs. For these types of systems the target return decays at a greater rate than the background clutter, thus making target detection difficult. In this paper, a technique is explored, based on frequency shifting the radar echo within the target, which serves to translate the position of the of the received target return to a higher frequency where the clutter is greatly reduced. It is shown, by means of a suitable design and simulation, that this approach may readily be used to achieve a much greater operating range in these types of location systems.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115622516","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875716
T. Rommel, M. Younis, G. Krieger
Synthetic aperture radar (SAR) with multiple transmit and receive channels (MIMO-SAR) has a higher flexibility and an improved efficiency compared to a conventional SAR system with a single channel. The multiple receive channels can be used, among other things, to increase the swath width at constant azimuth resolution or to suppress spatial interferences. However, multiple transmit channels, which transmit simultaneously in the same frequency band provide currently a challenge. Therefore, in this paper a modified chirp waveform is introduced which extends in combination with digital beam-forming (DBF) on receive the orthogonality condition to another degree of freedom, thus allowing in theory perfect orthogonality. Furthermore, the hardware design of the MIMO-Radar Demonstrator, a multichannel measurement system for radar and SAR applications is depicted. The shown measurement result demonstrates the possibility of obtaining all four parameters of the scattering matrix at the same time by transmitting orthogonal waveforms in different polarizations.
{"title":"An orthogonal waveform for fully polarimetric MIMO-SAR","authors":"T. Rommel, M. Younis, G. Krieger","doi":"10.1109/RADAR.2014.6875716","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875716","url":null,"abstract":"Synthetic aperture radar (SAR) with multiple transmit and receive channels (MIMO-SAR) has a higher flexibility and an improved efficiency compared to a conventional SAR system with a single channel. The multiple receive channels can be used, among other things, to increase the swath width at constant azimuth resolution or to suppress spatial interferences. However, multiple transmit channels, which transmit simultaneously in the same frequency band provide currently a challenge. Therefore, in this paper a modified chirp waveform is introduced which extends in combination with digital beam-forming (DBF) on receive the orthogonality condition to another degree of freedom, thus allowing in theory perfect orthogonality. Furthermore, the hardware design of the MIMO-Radar Demonstrator, a multichannel measurement system for radar and SAR applications is depicted. The shown measurement result demonstrates the possibility of obtaining all four parameters of the scattering matrix at the same time by transmitting orthogonal waveforms in different polarizations.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115348959","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875747
S. Searle, J. Palmer, L. Davis, D. O’Hagan, M. Ummenhofer
The presence of clutter in passive radar returns imposes a minimum floor level on the ambiguity surface, masking weak returns and reducing dynamic range. When the illuminating signal is a form of OFDM, orthogonality between subcarriers can be exploited to produce a zero floor within certain delay bins. In this paper we compare and contrast several such ambiguity processing techniques for general OFDM signals. The methods are applied to simulated and real DVB-T passive radar returns having a wide range of delays. It is shown that an OFDM-specific method can outperform a standard pulse-Doppler processing method under certain conditions. An example is provided using real German DVB-T data from Fraunhofer FHR.
{"title":"Evaluation of the ambiguity function for passive radar with OFDM transmissions","authors":"S. Searle, J. Palmer, L. Davis, D. O’Hagan, M. Ummenhofer","doi":"10.1109/RADAR.2014.6875747","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875747","url":null,"abstract":"The presence of clutter in passive radar returns imposes a minimum floor level on the ambiguity surface, masking weak returns and reducing dynamic range. When the illuminating signal is a form of OFDM, orthogonality between subcarriers can be exploited to produce a zero floor within certain delay bins. In this paper we compare and contrast several such ambiguity processing techniques for general OFDM signals. The methods are applied to simulated and real DVB-T passive radar returns having a wide range of delays. It is shown that an OFDM-specific method can outperform a standard pulse-Doppler processing method under certain conditions. An example is provided using real German DVB-T data from Fraunhofer FHR.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114602945","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875662
A. Wind, J. D. Gerber, J. Griesbach
The presence of large wind turbine farms has been shown to significantly degrade radar tracking of aircraft. The loss in localized radar coverage could pose issues in airspace management, especially within Temporary Flight Restrictions (TFR) areas. As wind turbine development expands, there is an increasing potential that the degraded radar tracking surveillance could negatively impact safety operations. Two analytical approaches are considered to compute the probability of successfully intercepting and escorting an unauthorized aircraft away from TFR controlled areas near wind turbines. New models, which were specifically designed to address wind turbine interference with ground-based radars, are utilized to simulate both the losses in radar tracking continuity from wind turbine obscuration and the resulting impact this has on airspace safety operations. Probability distributions are used to model intercept / escort processes including interceptor take-off times. A probability of success expected value is computed for candidate routes over a range of aircraft velocities. The intercept sequences are modeled under various conditions (no turbines, existing turbines, and expected future turbine development) to measure the contrast in probability of success lost as a direct result of turbines. Both Monte Carlo and convolutional “Direct Probability” approaches are considered.
{"title":"Impacts of wind turbine farm obscurations on aircraft escort probability of success","authors":"A. Wind, J. D. Gerber, J. Griesbach","doi":"10.1109/RADAR.2014.6875662","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875662","url":null,"abstract":"The presence of large wind turbine farms has been shown to significantly degrade radar tracking of aircraft. The loss in localized radar coverage could pose issues in airspace management, especially within Temporary Flight Restrictions (TFR) areas. As wind turbine development expands, there is an increasing potential that the degraded radar tracking surveillance could negatively impact safety operations. Two analytical approaches are considered to compute the probability of successfully intercepting and escorting an unauthorized aircraft away from TFR controlled areas near wind turbines. New models, which were specifically designed to address wind turbine interference with ground-based radars, are utilized to simulate both the losses in radar tracking continuity from wind turbine obscuration and the resulting impact this has on airspace safety operations. Probability distributions are used to model intercept / escort processes including interceptor take-off times. A probability of success expected value is computed for candidate routes over a range of aircraft velocities. The intercept sequences are modeled under various conditions (no turbines, existing turbines, and expected future turbine development) to measure the contrast in probability of success lost as a direct result of turbines. Both Monte Carlo and convolutional “Direct Probability” approaches are considered.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123105942","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875573
G. Cui, Jun Liu, Hongbin Li, B. Himed
This paper considers the problem of target detection in a passive radar consisting of a reference channel (RC) and a surveillance channel (SC). The RC receives an unknown source signal directly transmitted by a non-cooperative illuminator of opportunity (IO), whereas the SC collects target echoes due to the illumination by the same IO. The conventional solution to this passive detection problem is a cross-correlation (CC) based detector that cross-correlates the reference signal from the RC and the surveillance signal from the SC. It is known that the CC detector is very sensitive to the noise level in the RC. In this paper, we develop four detection algorithms based on the generalized likelihood ratio test principle, by treating the unknown source signal from the IO to be deterministic or stochastic and under conditions whether the noise variance is known or unknown. Our results demonstrate that when the reference signal is noisy, three of the proposed detectors offer significant improvements in detection performance over the CC detector.
{"title":"Target detection for passive radar with noisy reference channel","authors":"G. Cui, Jun Liu, Hongbin Li, B. Himed","doi":"10.1109/RADAR.2014.6875573","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875573","url":null,"abstract":"This paper considers the problem of target detection in a passive radar consisting of a reference channel (RC) and a surveillance channel (SC). The RC receives an unknown source signal directly transmitted by a non-cooperative illuminator of opportunity (IO), whereas the SC collects target echoes due to the illumination by the same IO. The conventional solution to this passive detection problem is a cross-correlation (CC) based detector that cross-correlates the reference signal from the RC and the surveillance signal from the SC. It is known that the CC detector is very sensitive to the noise level in the RC. In this paper, we develop four detection algorithms based on the generalized likelihood ratio test principle, by treating the unknown source signal from the IO to be deterministic or stochastic and under conditions whether the noise variance is known or unknown. Our results demonstrate that when the reference signal is noisy, three of the proposed detectors offer significant improvements in detection performance over the CC detector.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123679560","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875787
S. Villeval, I. Bilik, Sevgi Zübeyde Gürbuz
Pedestrian safety is one of the major tasks of automotive radars. Pedestrian detection in practical urban scenarios is challenging task due to the strong vertical and horizontal multipath phenomena from the asphalt roads and surrounding buildings, proximity to other obstacles with highradar cross section, and high probability of blockage by other targets. This work addresses the problem of joint pedestrian detection and classification in a practical urban environment by a 24 GHz FMCW automotive radar. The urban RF environment consisting of the asphalt road, vehicles and pedestrian was simulated. Micro-Doppler analysis was used to discriminate between pedestrians, vehicles, and animals. A variety of human activities, including mixed motion sequences were tested in target classification simulations.
{"title":"Application of a 24 GHz FMCW automotive radar for urban target classification","authors":"S. Villeval, I. Bilik, Sevgi Zübeyde Gürbuz","doi":"10.1109/RADAR.2014.6875787","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875787","url":null,"abstract":"Pedestrian safety is one of the major tasks of automotive radars. Pedestrian detection in practical urban scenarios is challenging task due to the strong vertical and horizontal multipath phenomena from the asphalt roads and surrounding buildings, proximity to other obstacles with highradar cross section, and high probability of blockage by other targets. This work addresses the problem of joint pedestrian detection and classification in a practical urban environment by a 24 GHz FMCW automotive radar. The urban RF environment consisting of the asphalt road, vehicles and pedestrian was simulated. Micro-Doppler analysis was used to discriminate between pedestrians, vehicles, and animals. A variety of human activities, including mixed motion sequences were tested in target classification simulations.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125369725","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 : 2014-05-19DOI: 10.1109/RADAR.2014.6875755
S. A. Askeland, T. Ekman
Automotive radar systems operating in urban areas phase a hard challenge detecting relevant targets since their signals are corrupted by strong clutter signals from the ground and surrounding buildings and because dense target scenarios may cause ambiguities. The combined FSK-LFMCW waveform by Rohling solves the range/velocity ambiguity within a short measurement time but the FFT used in the processing have limited resolution and large side lobe levels that are troublesome in dense target situations. In this paper we use the FSK-LFMCW waveform in an array system and define the target detection and parameter extraction as a 2D frequency estimation problem. We compare the performance of the non-parametric Capon and APES estimators with the regular FFT processing. The results show that we obtain better accuracy for the estimated target parameters and that we have a larger probability of target detection and a much smaller false alarm ratio.
{"title":"2D spectral estimation for unambiguous detection of automotive radar targets","authors":"S. A. Askeland, T. Ekman","doi":"10.1109/RADAR.2014.6875755","DOIUrl":"https://doi.org/10.1109/RADAR.2014.6875755","url":null,"abstract":"Automotive radar systems operating in urban areas phase a hard challenge detecting relevant targets since their signals are corrupted by strong clutter signals from the ground and surrounding buildings and because dense target scenarios may cause ambiguities. The combined FSK-LFMCW waveform by Rohling solves the range/velocity ambiguity within a short measurement time but the FFT used in the processing have limited resolution and large side lobe levels that are troublesome in dense target situations. In this paper we use the FSK-LFMCW waveform in an array system and define the target detection and parameter extraction as a 2D frequency estimation problem. We compare the performance of the non-parametric Capon and APES estimators with the regular FFT processing. The results show that we obtain better accuracy for the estimated target parameters and that we have a larger probability of target detection and a much smaller false alarm ratio.","PeriodicalId":127690,"journal":{"name":"2014 IEEE Radar Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126132771","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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