Pub Date : 2009-03-07DOI: 10.1109/AERO.2009.4839315
K. Clark, G. Tan-Wang, J. Boldt, R. Greeley, I. Jun, R. Lock, J. Ludwinski, R. Pappalardo, T. van Houten, T. Yan
Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO).
{"title":"Return to Europa: Overview of the Jupiter Europa Orbiter mission","authors":"K. Clark, G. Tan-Wang, J. Boldt, R. Greeley, I. Jun, R. Lock, J. Ludwinski, R. Pappalardo, T. van Houten, T. Yan","doi":"10.1109/AERO.2009.4839315","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839315","url":null,"abstract":"Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO).","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116037011","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839322
Mark Anderson, A. Allwood
A Meta-Stable Helium (MSHe) extraction method has been developed for In Situ chemical analysis of rocks and soils. MSHe provides soft-ionization and desorption of organics from soil and rocks without the use of solvents or high temperatures. This enables rapid, simple and effective extraction of analytes for very sensitive chemical analysis. The work presented extends the MSHe sampling from mass spectroscopy to other analytical methods including Surface Enhanced Raman spectroscopy (SERS). Applications include in situ analysis of planetary samples as well as current research on ancient sedimentary rocks that potentially contain microbial remains on Earth. The new sampling technology provides a powerful and widely applicable sampling tool for planetary and astrobiology science requiring in situ organic analysis.
{"title":"In situ sampling using Meta-Stable Helium","authors":"Mark Anderson, A. Allwood","doi":"10.1109/AERO.2009.4839322","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839322","url":null,"abstract":"A Meta-Stable Helium (MSHe) extraction method has been developed for In Situ chemical analysis of rocks and soils. MSHe provides soft-ionization and desorption of organics from soil and rocks without the use of solvents or high temperatures. This enables rapid, simple and effective extraction of analytes for very sensitive chemical analysis. The work presented extends the MSHe sampling from mass spectroscopy to other analytical methods including Surface Enhanced Raman spectroscopy (SERS). Applications include in situ analysis of planetary samples as well as current research on ancient sedimentary rocks that potentially contain microbial remains on Earth. The new sampling technology provides a powerful and widely applicable sampling tool for planetary and astrobiology science requiring in situ organic analysis.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116951421","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839512
Neil Steiner, P. Athanas
Autonomous capability in space systems is rapidly becoming a necessity for continued research and exploration. While these systems have traditionally behaved as passive observers, their remoteness and unique access to unexplored environments will likely result in future systems that behave more like active agents employed on our behalf. We may still determine the larger mission goals and priorities, but the systems themselves will be better able to direct their own movement, schedule, and operation.
{"title":"Hardware autonomy and space systems","authors":"Neil Steiner, P. Athanas","doi":"10.1109/AERO.2009.4839512","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839512","url":null,"abstract":"Autonomous capability in space systems is rapidly becoming a necessity for continued research and exploration. While these systems have traditionally behaved as passive observers, their remoteness and unique access to unexplored environments will likely result in future systems that behave more like active agents employed on our behalf. We may still determine the larger mission goals and priorities, but the systems themselves will be better able to direct their own movement, schedule, and operation.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116326099","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839691
M. Schwabacher, R. Aguilar, F. Figueroa
The goal of this work was to use data-driven methods to automatically detect and isolate faults in the J-2X rocket engine. It was decided to use decision trees, since they tend to be easier to interpret than other data-driven methods. The decision tree algorithm automatically “learns” a decision tree by performing a search through the space of possible decision trees to find one that fits the training data (with the hope that this tree will also generalize to new data). The particular decision tree algorithm used is known as C4.5. Simulated J-2X data from a high-fidelity simulator developed at Pratt & Whitney Rocketdyne and known as the Detailed Real-Time Model (DRTM) was used to “train” and test the decision tree. Fifty-six DRTM simulations were performed for this purpose, with different leak sizes, different leak locations, and different times of leak onset. To make the simulations as realistic as possible, they included simulated sensor noise, and included a gradual degradation in both fuel and oxidizer turbine efficiency. A decision tree was trained using 11 of these simulations, and tested using the remaining 45 simulations. In the training phase, the C4.5 algorithm was provided with labeled examples of data from nominal operation and data including leaks in each leak location. From the data, it “learned” a decision tree that can classify unseen data as having no leak or having a leak in one of the five leak locations. In the test phase, the decision tree produced very low false alarm rates and low missed detection rates on the unseen data. It had very good fault isolation rates for three of the five simulated leak locations, but it tended to confuse the remaining two locations, perhaps because a large leak at one of these two locations can look very similar to a small leak at the other location.
{"title":"Using decision trees to detect and isolate simulated leaks in the J-2X rocket engine","authors":"M. Schwabacher, R. Aguilar, F. Figueroa","doi":"10.1109/AERO.2009.4839691","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839691","url":null,"abstract":"The goal of this work was to use data-driven methods to automatically detect and isolate faults in the J-2X rocket engine. It was decided to use decision trees, since they tend to be easier to interpret than other data-driven methods. The decision tree algorithm automatically “learns” a decision tree by performing a search through the space of possible decision trees to find one that fits the training data (with the hope that this tree will also generalize to new data). The particular decision tree algorithm used is known as C4.5. Simulated J-2X data from a high-fidelity simulator developed at Pratt & Whitney Rocketdyne and known as the Detailed Real-Time Model (DRTM) was used to “train” and test the decision tree. Fifty-six DRTM simulations were performed for this purpose, with different leak sizes, different leak locations, and different times of leak onset. To make the simulations as realistic as possible, they included simulated sensor noise, and included a gradual degradation in both fuel and oxidizer turbine efficiency. A decision tree was trained using 11 of these simulations, and tested using the remaining 45 simulations. In the training phase, the C4.5 algorithm was provided with labeled examples of data from nominal operation and data including leaks in each leak location. From the data, it “learned” a decision tree that can classify unseen data as having no leak or having a leak in one of the five leak locations. In the test phase, the decision tree produced very low false alarm rates and low missed detection rates on the unseen data. It had very good fault isolation rates for three of the five simulated leak locations, but it tended to confuse the remaining two locations, perhaps because a large leak at one of these two locations can look very similar to a small leak at the other location.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116374705","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839406
R. Prabhu, E. Grayver
OFDM is a widely adopted modulation technique for wireless communication. However, the OFDM waveform still suffers from a large peak-to-average power ratio (PAR). Larger PAR leads to higher transmit power inefficiency. In this paper, we compare two constellation modification techniques, constellation distortion (CD) and active constellation extension (ACE), to reduce the PAR of the OFDM waveform. Both techniques are similar, in the sense that the constellation symbols are modified to reduce PAR. In CD, the tradeoff is between PAR reduction and added distortion, which results in a larger bit error rate (BER). In ACE, the tradeoff is between added power and PAR reduction. A metric called normalized total power (NTP) is introduced to facilitate a comparison between these two different techniques. Using this metric, we compare the performance of the two techniques using an 802.11a OFDM waveform. We present comparisons, via simulation, in both coded and uncoded cases. The simulation results show that, for an uncoded OFDM system, ACE performs better than CD for all constellations except QPSK. However, CD is preferred over ACE when coding is present. NTP improvements using CD can be up to 4.1dB in the case of coded QPSK and up to 0.8 dB using ACE for uncoded QPSK.
{"title":"Active constellation modification techniques for OFDM PAR reduction","authors":"R. Prabhu, E. Grayver","doi":"10.1109/AERO.2009.4839406","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839406","url":null,"abstract":"OFDM is a widely adopted modulation technique for wireless communication. However, the OFDM waveform still suffers from a large peak-to-average power ratio (PAR). Larger PAR leads to higher transmit power inefficiency. In this paper, we compare two constellation modification techniques, constellation distortion (CD) and active constellation extension (ACE), to reduce the PAR of the OFDM waveform. Both techniques are similar, in the sense that the constellation symbols are modified to reduce PAR. In CD, the tradeoff is between PAR reduction and added distortion, which results in a larger bit error rate (BER). In ACE, the tradeoff is between added power and PAR reduction. A metric called normalized total power (NTP) is introduced to facilitate a comparison between these two different techniques. Using this metric, we compare the performance of the two techniques using an 802.11a OFDM waveform. We present comparisons, via simulation, in both coded and uncoded cases. The simulation results show that, for an uncoded OFDM system, ACE performs better than CD for all constellations except QPSK. However, CD is preferred over ACE when coding is present. NTP improvements using CD can be up to 4.1dB in the case of coded QPSK and up to 0.8 dB using ACE for uncoded QPSK.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115173169","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839342
M. Calamia, G. Franceschetti, R. Lanari, F. Casu, M. Manzo
We compare the surface deformation measurement capability of the Small BAseline Subset (SBAS) DInSAR technique and of the continuous Global Positioning System (GPS). The analysis is focused on the Los Angeles (California) test area where different deformation phenomena occur and a large amount of SAR data, acquired by the European Remote Sensing Satellite (ERS) sensors, and of continuous GPS measurements is available. Our analysis shows that the SBAS technique allows to achieve an estimate of the single displacement measurements, in the radar line of sight (LOS), with a standard deviation of about 5mm, which is comparable with the LOS-projected GPS data accuracy. A final discussion on the complementariness and integration of SAR and GPS measurements is provided.
{"title":"Comparison and integration of GPS and DInSAR deformation time-series","authors":"M. Calamia, G. Franceschetti, R. Lanari, F. Casu, M. Manzo","doi":"10.1109/AERO.2009.4839342","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839342","url":null,"abstract":"We compare the surface deformation measurement capability of the Small BAseline Subset (SBAS) DInSAR technique and of the continuous Global Positioning System (GPS). The analysis is focused on the Los Angeles (California) test area where different deformation phenomena occur and a large amount of SAR data, acquired by the European Remote Sensing Satellite (ERS) sensors, and of continuous GPS measurements is available. Our analysis shows that the SBAS technique allows to achieve an estimate of the single displacement measurements, in the radar line of sight (LOS), with a standard deviation of about 5mm, which is comparable with the LOS-projected GPS data accuracy. A final discussion on the complementariness and integration of SAR and GPS measurements is provided.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116073662","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839715
R. Kohli, J. Fishman, M. Hyatt, P. Abel, P. DeLaune
The NASA Lunar Dust Management Project (DMP) has been established to address relevant high priority needs for lunar dust mitigation technologies to be used during lunar surface operations. To this end, an important goal of the project is to ensure that DMP only invests in research and technologies (R&T) that have been assessed and prioritized to meet NASA needs for lunar exploration. To facilitate the process, comparison/decision criteria were developed to assess and prioritize internal and external technology solution alternatives. This paper describes the technologies and presents the assessment methodology.
{"title":"Achieving a prioritized research & technology development portfolio for the Dust Management Project","authors":"R. Kohli, J. Fishman, M. Hyatt, P. Abel, P. DeLaune","doi":"10.1109/AERO.2009.4839715","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839715","url":null,"abstract":"The NASA Lunar Dust Management Project (DMP) has been established to address relevant high priority needs for lunar dust mitigation technologies to be used during lunar surface operations. To this end, an important goal of the project is to ensure that DMP only invests in research and technologies (R&T) that have been assessed and prioritized to meet NASA needs for lunar exploration. To facilitate the process, comparison/decision criteria were developed to assess and prioritize internal and external technology solution alternatives. This paper describes the technologies and presents the assessment methodology.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117016621","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839683
Eric Rabeno, Mark S. Bounds
The performance of military ground vehicle systems quickly degrades due to high operation tempo and extreme environments while performing in-theater service. Current maintenance methods associated with this degradation are not sufficiently optimized for cost and performance. To address this issue, the United States Army is implementing a policy of Condition Based Maintenance (CBM) and being supported by the Army Materiel System Analysis Activity (AMSAA). CBM is a plan of maintenance for a system based upon the actual condition of the system as enabled by the application of usage, diagnostic and prognostic processes executed on a Health and Usage Monitoring System (HUMS). AMSAA has developed and is implementing a CBM system for ground vehicles. This development process has included the development of a robust military-grade HUMS in conjunction with the Aberdeen Test Center and the development of data collection, reduction, analysis, and reporting processes. A key requirement underlying these processes is a thorough understanding of both the ways in which system condition is degenerated and the ability of the HUMS to detect, identify, and communicate all conditions that requires maintenance in a timely manner. AMSAA and the US Army Aberdeen Test Center (ATC) have jointly initiated testing and applications as the critical means of filling this requirement.
{"title":"Condition based maintenance of military ground vehicles","authors":"Eric Rabeno, Mark S. Bounds","doi":"10.1109/AERO.2009.4839683","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839683","url":null,"abstract":"The performance of military ground vehicle systems quickly degrades due to high operation tempo and extreme environments while performing in-theater service. Current maintenance methods associated with this degradation are not sufficiently optimized for cost and performance. To address this issue, the United States Army is implementing a policy of Condition Based Maintenance (CBM) and being supported by the Army Materiel System Analysis Activity (AMSAA). CBM is a plan of maintenance for a system based upon the actual condition of the system as enabled by the application of usage, diagnostic and prognostic processes executed on a Health and Usage Monitoring System (HUMS). AMSAA has developed and is implementing a CBM system for ground vehicles. This development process has included the development of a robust military-grade HUMS in conjunction with the Aberdeen Test Center and the development of data collection, reduction, analysis, and reporting processes. A key requirement underlying these processes is a thorough understanding of both the ways in which system condition is degenerated and the ability of the HUMS to detect, identify, and communicate all conditions that requires maintenance in a timely manner. AMSAA and the US Army Aberdeen Test Center (ATC) have jointly initiated testing and applications as the critical means of filling this requirement.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115317754","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839608
P. Wu, D. Campbell, T. Merz
A system for automated mission planning is presented with a view to operate Unmanned Aerial Vehicles (UAVs) in the National Airspace System (NAS). This paper describes methods for modelling decision variables, for enroute flight planning under Visual Flight Rules (VFR). For demonstration purposes, the task of delivering a medical package to a remote location was chosen. Decision variables include fuel consumption, flight time, wind and weather conditions, terrain elevation, airspace classification and the flight trajectories of other aircraft. The decision variables are transformed, using a Multi-Criteria Decision Making (MCDM) cost function, into a single cost value for a grid-based search algorithm (e.g. A*). It is shown that the proposed system provides a means for fast, autonomous generation of near-optimal flight plans, which in turn are a key enabler in the operation of UAVs in the NAS.
{"title":"On-board multi-objective mission planning for Unmanned Aerial Vehicles","authors":"P. Wu, D. Campbell, T. Merz","doi":"10.1109/AERO.2009.4839608","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839608","url":null,"abstract":"A system for automated mission planning is presented with a view to operate Unmanned Aerial Vehicles (UAVs) in the National Airspace System (NAS). This paper describes methods for modelling decision variables, for enroute flight planning under Visual Flight Rules (VFR). For demonstration purposes, the task of delivering a medical package to a remote location was chosen. Decision variables include fuel consumption, flight time, wind and weather conditions, terrain elevation, airspace classification and the flight trajectories of other aircraft. The decision variables are transformed, using a Multi-Criteria Decision Making (MCDM) cost function, into a single cost value for a grid-based search algorithm (e.g. A*). It is shown that the proposed system provides a means for fast, autonomous generation of near-optimal flight plans, which in turn are a key enabler in the operation of UAVs in the NAS.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121708171","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 : 2009-03-07DOI: 10.1109/AERO.2009.4839474
H. Ghaemi, M. Galletti, T. Boerner, F. Gekat, M. Viberg
The maximum obtainable resolution of a strip-map synthetic aperture radar (SAR) system can be retained by simply avoiding weighting, or tapering, data samples in the along-track compression process. However, this will lead to hazardous artifacts caused by strong sidelobes of the corresponding adjacent scatterers whose interference might severely weaken the desired targets or even introduce false targets. On the other hand, some residual artifacts, even after tapering process, may still deteriorate the quality (contrast) of the SAR image. These issues can be remedied by applying the so-called CLEAN technique, which can mitigate these ill-effects in strip-map SAR imagery while maintaining the maximum resolution. This, indeed, is carried out as a post processing step, i.e., after the azimuth compression is accomplished, in the SAR system. The objective of this paper is to extend the CLEAN technique to strip-map SAR system to produce high-quality images with a very good along-track resolution. The algorithm is then applied to data from a ground-based circular SAR (CSAR) system to verify its implementation as well as this new application of the CLEAN technique.
{"title":"CLEAN technique in strip-map SAR for high-quality imaging","authors":"H. Ghaemi, M. Galletti, T. Boerner, F. Gekat, M. Viberg","doi":"10.1109/AERO.2009.4839474","DOIUrl":"https://doi.org/10.1109/AERO.2009.4839474","url":null,"abstract":"The maximum obtainable resolution of a strip-map synthetic aperture radar (SAR) system can be retained by simply avoiding weighting, or tapering, data samples in the along-track compression process. However, this will lead to hazardous artifacts caused by strong sidelobes of the corresponding adjacent scatterers whose interference might severely weaken the desired targets or even introduce false targets. On the other hand, some residual artifacts, even after tapering process, may still deteriorate the quality (contrast) of the SAR image. These issues can be remedied by applying the so-called CLEAN technique, which can mitigate these ill-effects in strip-map SAR imagery while maintaining the maximum resolution. This, indeed, is carried out as a post processing step, i.e., after the azimuth compression is accomplished, in the SAR system. The objective of this paper is to extend the CLEAN technique to strip-map SAR system to produce high-quality images with a very good along-track resolution. The algorithm is then applied to data from a ground-based circular SAR (CSAR) system to verify its implementation as well as this new application of the CLEAN technique.","PeriodicalId":117250,"journal":{"name":"2009 IEEE Aerospace conference","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123514424","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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