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.1990.201188
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.1990.201190
J. Lee, E.G. Baxa
Accurate weather spectrum moment estimation is important in the use of weather radar for hazardous windshear detection. The effect of the stable local oscillator (STALO) instability (jitter) on the spectrum moment estimation algorithm is investigated. Uncertainty in the stable local oscillator will affect both the transmitted signal and the received signal since the STALO provides transmitted and reference carriers. The proposed approach models STALO phase jitter as it affects the complex autocorrelation of the radar return. The results can therefore be interpreted in terms of any source of system phase jitter for which the model is appropriate and, in particular, may be considered as a cumulative effect of all radar system sources.<>
{"title":"Phase noise effects on turbulent weather radar spectrum parameter estimation","authors":"J. Lee, E.G. Baxa","doi":"10.1109/RADAR.1990.201190","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201190","url":null,"abstract":"Accurate weather spectrum moment estimation is important in the use of weather radar for hazardous windshear detection. The effect of the stable local oscillator (STALO) instability (jitter) on the spectrum moment estimation algorithm is investigated. Uncertainty in the stable local oscillator will affect both the transmitted signal and the received signal since the STALO provides transmitted and reference carriers. The proposed approach models STALO phase jitter as it affects the complex autocorrelation of the radar return. The results can therefore be interpreted in terms of any source of system phase jitter for which the model is appropriate and, in particular, may be considered as a cumulative effect of all radar system sources.<<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":"126743125","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.1990.201112
D. C. Lush
The ambiguity function is derived for a pulse Doppler radar which uses fill pulses, a moving target indicator, a (MTI) filter, and DFT (discrete Fourier transform) processing. Some special properties of the pulse Doppler radar ambiguity function and its correspondence with the autoambiguity function of a pulse train as a special case are described. Examples illustrating the utility of the ambiguity function in describing the interaction of the radar with its clutter environment, including transient effects, are presented.<>
{"title":"Airborne radar analysis using the ambiguity function","authors":"D. C. Lush","doi":"10.1109/RADAR.1990.201112","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201112","url":null,"abstract":"The ambiguity function is derived for a pulse Doppler radar which uses fill pulses, a moving target indicator, a (MTI) filter, and DFT (discrete Fourier transform) processing. Some special properties of the pulse Doppler radar ambiguity function and its correspondence with the autoambiguity function of a pulse train as a special case are described. Examples illustrating the utility of the ambiguity function in describing the interaction of the radar with its clutter environment, including transient effects, are presented.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"11 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":"124185542","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.1990.201189
J. Chao, C.M. Cheng, C. Su
Moving target detector (MTD) related multiple-hypothesis testing is considered, and the Dempster-Shafer theory is applied to this problem. Feature parameters are extracted from radar signals, and the value of each feature parameter is interpreted in terms of Dempster-Shafer's belief or disbelief for the associated hypotheses. Using Dempster's combining rule, a generalized likelihood ratio test is derived.<>
{"title":"A moving target detector based on information fusion","authors":"J. Chao, C.M. Cheng, C. Su","doi":"10.1109/RADAR.1990.201189","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201189","url":null,"abstract":"Moving target detector (MTD) related multiple-hypothesis testing is considered, and the Dempster-Shafer theory is applied to this problem. Feature parameters are extracted from radar signals, and the value of each feature parameter is interpreted in terms of Dempster-Shafer's belief or disbelief for the associated hypotheses. Using Dempster's combining rule, a generalized likelihood ratio test is derived.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"32 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":"127116828","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.1990.201147
G. Schrick, R. G. Wiley
The interception problem is reviewed, an LPI radar design is examined and the performance of intercept receivers of the future is considered. The receiver needed to intercept LPI signals must respond across a broad band and provide noncoherent integration capabilities over times comparable to the coherent (or noncoherent) integration times used by radars. One useful receiver design is the rapidly swept superheterodyne receiver (RSSR). The band must be swept in a time which is short compared to the time the radar signal dwells at one frequency. The IF bandwidth of the RSSR must be wide enough to accommodate the pulse compression phase/frequency modulation used by the radar.<>
{"title":"Interception of LPI radar signals","authors":"G. Schrick, R. G. Wiley","doi":"10.1109/RADAR.1990.201147","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201147","url":null,"abstract":"The interception problem is reviewed, an LPI radar design is examined and the performance of intercept receivers of the future is considered. The receiver needed to intercept LPI signals must respond across a broad band and provide noncoherent integration capabilities over times comparable to the coherent (or noncoherent) integration times used by radars. One useful receiver design is the rapidly swept superheterodyne receiver (RSSR). The band must be swept in a time which is short compared to the time the radar signal dwells at one frequency. The IF bandwidth of the RSSR must be wide enough to accommodate the pulse compression phase/frequency modulation used by the radar.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"95 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":"128019286","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.1990.201116
G. Albano, S. Cacopardi, G. Fedele
A Doppler correlation technique to extract target velocity data in MPRF (medium pulse repetition frequency) radars by starting from ambiguous measurements is presented. A two-step procedure that assures satisfactory performance for a multiple target environment and frequency agile radars is proposed. The performances have been assessed through a computer simulation which allowed the selection of the best values for Doppler coincidence threshold K and filter enlargement beta . In particular, the values K=L-1 and beta =30% represent the best tradeoff, since they give a probability of correct velocity resolution greater than 99.5%. It is shown that the velocity correlation algorithm can also operate as a deghosting filter.<>
{"title":"Resolution of velocity ambiguities for MPRE frequency agile radars in multiple target environment","authors":"G. Albano, S. Cacopardi, G. Fedele","doi":"10.1109/RADAR.1990.201116","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201116","url":null,"abstract":"A Doppler correlation technique to extract target velocity data in MPRF (medium pulse repetition frequency) radars by starting from ambiguous measurements is presented. A two-step procedure that assures satisfactory performance for a multiple target environment and frequency agile radars is proposed. The performances have been assessed through a computer simulation which allowed the selection of the best values for Doppler coincidence threshold K and filter enlargement beta . In particular, the values K=L-1 and beta =30% represent the best tradeoff, since they give a probability of correct velocity resolution greater than 99.5%. It is shown that the velocity correlation algorithm can also operate as a deghosting filter.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":"32 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":"127222697","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.1990.201184
G. Trunk, J.D. Wilson, P. Hughes
A simple processing algorithm for performing long-term integration is developed and evaluated. The key step in the procedure is to make multiple ambiguous velocity estimates and use these velocity estimates to compensate for all possible target motions. Using simulation techniques, the probabilities of false alarm and detection are evaluated.<>
{"title":"Long term integration using a phased array radar","authors":"G. Trunk, J.D. Wilson, P. Hughes","doi":"10.1109/RADAR.1990.201184","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201184","url":null,"abstract":"A simple processing algorithm for performing long-term integration is developed and evaluated. The key step in the procedure is to make multiple ambiguous velocity estimates and use these velocity estimates to compensate for all possible target motions. Using simulation techniques, the probabilities of false alarm and detection are evaluated.<<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":"124300139","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.1990.201080
U. Nickel
The question of what concept should be chosen for the case of an active, two-dimensional electronically scanning ground-based radar with many elements for jammer suppression in a dense jamming environment is discussed. The nonadaptive low sidelobe antenna is compared with the adaptive antenna. Although both antennas have the same performance for sidelobe jammers, the low-sidelobe (LS) antenna is vulnerable to main beam jamming. For multiple jammers this prevents radar operation with the LS-antenna, whereas the adaptive antenna is able to look through between the jammers. Practical aspects such as the generation of adaptive channels, channel accuracy, and ground reflections are mentioned.<>
{"title":"Comparison of a non-adaptive low-sidelobe array antenna with an adaptive phased array antenna","authors":"U. Nickel","doi":"10.1109/RADAR.1990.201080","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201080","url":null,"abstract":"The question of what concept should be chosen for the case of an active, two-dimensional electronically scanning ground-based radar with many elements for jammer suppression in a dense jamming environment is discussed. The nonadaptive low sidelobe antenna is compared with the adaptive antenna. Although both antennas have the same performance for sidelobe jammers, the low-sidelobe (LS) antenna is vulnerable to main beam jamming. For multiple jammers this prevents radar operation with the LS-antenna, whereas the adaptive antenna is able to look through between the jammers. Practical aspects such as the generation of adaptive channels, channel accuracy, and ground reflections are mentioned.<<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":"123496942","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.1990.201137
A. Moreira
A multilook technique for improving the radiometric resolution in SAR image formation without altering the geometric resolution of the impulse response is proposed. This technique is based on the formation of looks with different bandwidths. The final image is formed by giving each look a proper size and weighting and then adding them incoherently. The looks with larger bandwidth contribute to an improvement of the overall geometric resolution, while the looks with smaller bandwidth improve the overall radiometric resolution. The equivalent number of looks is more than 2.3 times the number of independent looks and is superior to conventional multilook processing with overlapping. An algorithm for efficient processing using the proposed technique is presented, and its validity is proved by image comparison and analysis.<>
{"title":"An improved multi-look technique to produce SAR imagery","authors":"A. Moreira","doi":"10.1109/RADAR.1990.201137","DOIUrl":"https://doi.org/10.1109/RADAR.1990.201137","url":null,"abstract":"A multilook technique for improving the radiometric resolution in SAR image formation without altering the geometric resolution of the impulse response is proposed. This technique is based on the formation of looks with different bandwidths. The final image is formed by giving each look a proper size and weighting and then adding them incoherently. The looks with larger bandwidth contribute to an improvement of the overall geometric resolution, while the looks with smaller bandwidth improve the overall radiometric resolution. The equivalent number of looks is more than 2.3 times the number of independent looks and is superior to conventional multilook processing with overlapping. An algorithm for efficient processing using the proposed technique is presented, and its validity is proved by image comparison and analysis.<<ETX>>","PeriodicalId":441674,"journal":{"name":"IEEE International Conference on Radar","volume":" 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131942186","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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