The bispectral signatures of backscattered radar signals are examined. An interpretation of these signatures in terms of multiple scattering interactions is presented. A high resolution bispectral estimation technique is used to resolve nearly located target scattering centers.<>
{"title":"High resolution bispectral estimation of radar signals","authors":"I. Jouny","doi":"10.1109/NTC.1994.316651","DOIUrl":"https://doi.org/10.1109/NTC.1994.316651","url":null,"abstract":"The bispectral signatures of backscattered radar signals are examined. An interpretation of these signatures in terms of multiple scattering interactions is presented. A high resolution bispectral estimation technique is used to resolve nearly located target scattering centers.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"34 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121003618","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. Nouel, J. Berthias, M. Deleuze, C. Jayles, P. Laudet
Summary form only given, as follows. The Centre National d'Etudes Spatiales (CNES) has developed an orbitography system called DORIS. From a network of about 50 ground beacons, the onboard receiver measures the Doppler effects. Such a system is currently performing on the French SPOT2 and SPOT3 imagery satellites. DORIS plays a fundamental role in the TOPEX/POSEIDON orbit computation with an accuracy of a few centimeters. A real time onboard orbit determination device named DIODE will be added to the following receivers. It is based on a Kalman filtering of the dense coverage tracking measurements on a 1750 computer using mainly ADA language. DORIS and DIODE will be on SPOT4, TPFO and ENVISAT satellites.<>
{"title":"DORIS and its companion DIODE: a dedicated system for orbit determination","authors":"P. Nouel, J. Berthias, M. Deleuze, C. Jayles, P. Laudet","doi":"10.1109/NTC.1994.316680","DOIUrl":"https://doi.org/10.1109/NTC.1994.316680","url":null,"abstract":"Summary form only given, as follows. The Centre National d'Etudes Spatiales (CNES) has developed an orbitography system called DORIS. From a network of about 50 ground beacons, the onboard receiver measures the Doppler effects. Such a system is currently performing on the French SPOT2 and SPOT3 imagery satellites. DORIS plays a fundamental role in the TOPEX/POSEIDON orbit computation with an accuracy of a few centimeters. A real time onboard orbit determination device named DIODE will be added to the following receivers. It is based on a Kalman filtering of the dense coverage tracking measurements on a 1750 computer using mainly ADA language. DORIS and DIODE will be on SPOT4, TPFO and ENVISAT satellites.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128633040","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 architecture of the system designed to enable DirecTv and United States Satellite Broadcasting to deliver large volumes of programming and information directly to customers homes is described. The design constraints and tradeoffs that lead to the system design and the resulting functional capabilities are also discussed.<>
{"title":"Architecture of the first US direct broadcast satellite system","authors":"L. Butterworth","doi":"10.1109/NTC.1994.316674","DOIUrl":"https://doi.org/10.1109/NTC.1994.316674","url":null,"abstract":"The architecture of the system designed to enable DirecTv and United States Satellite Broadcasting to deliver large volumes of programming and information directly to customers homes is described. The design constraints and tradeoffs that lead to the system design and the resulting functional capabilities are also discussed.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124739173","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}
On-site high power radiation is an essential component of the active-array transmit-channel testing and antenna burn-in. Computer modeling is well-suited to approximate near-field and far-field power densities of microwave radiation around antenna arrays. Because of safety considerations involving such emissions, an accurate representation of RF field strengths at critical locations was needed. The investigators used the MATLAB programming language to model the radiation field characteristics and RF power densities. Results from the computer-models, an essential part of this hazard analysis, were used to assess the risks the safety hazards presented. Two methods were used to generate power density models. The first, an exact theoretical approach, modeled the radiating elements as simple electric dipoles. The second was a simplified approach using estimates of the element pattern.<>
{"title":"RF radiation hazard analysis at Crane Division, Naval Surface Warfare Center","authors":"D.P. Woollen, W. A. Wood, J. Pankow","doi":"10.1109/NTC.1994.316653","DOIUrl":"https://doi.org/10.1109/NTC.1994.316653","url":null,"abstract":"On-site high power radiation is an essential component of the active-array transmit-channel testing and antenna burn-in. Computer modeling is well-suited to approximate near-field and far-field power densities of microwave radiation around antenna arrays. Because of safety considerations involving such emissions, an accurate representation of RF field strengths at critical locations was needed. The investigators used the MATLAB programming language to model the radiation field characteristics and RF power densities. Results from the computer-models, an essential part of this hazard analysis, were used to assess the risks the safety hazards presented. Two methods were used to generate power density models. The first, an exact theoretical approach, modeled the radiating elements as simple electric dipoles. The second was a simplified approach using estimates of the element pattern.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129751604","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}
Aerodromes are becoming a bottleneck in the crowded air transport system; better safety, efficiency as well as the maintenance or increase of the aerodrome capacity (even in adverse weather conditions) call for better performance and enhanced architectures for the surface movements guidance and control systems, needed to overcome the limitations of today's (basically manual) systems. Advanced functions include an enhanced surveillance sub-system using new radar systems. The paper contains: description of the environment, surveillance requirements, radar requirements and finally the description of an advanced solution based on millimeter-wave "miniradars".<>
{"title":"Advanced radar techniques for the air transport system: the surface movement miniradar concept","authors":"G. Galati, M. Ferri, F. Marti","doi":"10.1109/NTC.1994.316657","DOIUrl":"https://doi.org/10.1109/NTC.1994.316657","url":null,"abstract":"Aerodromes are becoming a bottleneck in the crowded air transport system; better safety, efficiency as well as the maintenance or increase of the aerodrome capacity (even in adverse weather conditions) call for better performance and enhanced architectures for the surface movements guidance and control systems, needed to overcome the limitations of today's (basically manual) systems. Advanced functions include an enhanced surveillance sub-system using new radar systems. The paper contains: description of the environment, surveillance requirements, radar requirements and finally the description of an advanced solution based on millimeter-wave \"miniradars\".<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117265037","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}
Summary form only given, as follows. The employment of sub-milliradian infrared measurement sensors in an airborne platform requires extraordinary techniques to permit the attainment of the parameter accuracy in Earth coordinates vs aircraft coordinates. The airborne platform, in general, contains a GPS/INS system located at the approximate center of gravity. The sensors, in general, are located at the extremities of the aircraft. As a result, static and dynamic (i.e. flexure) errors must be calibrated to permit accurate passive measurements of azimuth and elevation angles to an airborne target. The high frequency, dynamic flexure of the sensor location is usually measured and corrected for by a second INS unit collocated with the sensor. Static offset errors due to aircraft flexure under different aircraft maneuvering conditions can usually be measured by commanding the aircraft through a maneuver sequence and comparing the differences in the two INS units. The results may be stored for subsequent corrections using a table-lookup procedure. Over longer time span (minutes and hours), drift errors of the INS will introduce large attitude uncertainties in the sensor angular output, which if uncorrected, will introduce large positional uncertainities in Earth coordinates of the measured objects. The long term drift errors, however, can be corrected by periodic in-flight observations of known infrared stars. With the improved sensitivities and large areal coverage of the current generation of infrared focal plane arrays, there are sufficient number of stars that could be conveniently observed at periodic intervals at aircraft altitude in both day and night to permit absolute positional calibration of the sensor in real-time. Preliminary ground-based measurements of airborne objects have been obtained with sensors having angular resolution and sensitivity typical of airborne sensors to allow evaluation of the expected calibration performance. By incorporating a sequence of in-flight calibration procedures employing the aircraft GPS/INS, the sensor INS, and periodic star observations under specific sequence, it is expected that the absolute attitude of an airborne IR sensor can be calibrated to within a small part of the instantaneous field of view of the sensor system.<>
{"title":"Airborne infrared sensor calibration","authors":"M. O'Connor, L. Smith, L. Cheung","doi":"10.1109/NTC.1994.316697","DOIUrl":"https://doi.org/10.1109/NTC.1994.316697","url":null,"abstract":"Summary form only given, as follows. The employment of sub-milliradian infrared measurement sensors in an airborne platform requires extraordinary techniques to permit the attainment of the parameter accuracy in Earth coordinates vs aircraft coordinates. The airborne platform, in general, contains a GPS/INS system located at the approximate center of gravity. The sensors, in general, are located at the extremities of the aircraft. As a result, static and dynamic (i.e. flexure) errors must be calibrated to permit accurate passive measurements of azimuth and elevation angles to an airborne target. The high frequency, dynamic flexure of the sensor location is usually measured and corrected for by a second INS unit collocated with the sensor. Static offset errors due to aircraft flexure under different aircraft maneuvering conditions can usually be measured by commanding the aircraft through a maneuver sequence and comparing the differences in the two INS units. The results may be stored for subsequent corrections using a table-lookup procedure. Over longer time span (minutes and hours), drift errors of the INS will introduce large attitude uncertainties in the sensor angular output, which if uncorrected, will introduce large positional uncertainities in Earth coordinates of the measured objects. The long term drift errors, however, can be corrected by periodic in-flight observations of known infrared stars. With the improved sensitivities and large areal coverage of the current generation of infrared focal plane arrays, there are sufficient number of stars that could be conveniently observed at periodic intervals at aircraft altitude in both day and night to permit absolute positional calibration of the sensor in real-time. Preliminary ground-based measurements of airborne objects have been obtained with sensors having angular resolution and sensitivity typical of airborne sensors to allow evaluation of the expected calibration performance. By incorporating a sequence of in-flight calibration procedures employing the aircraft GPS/INS, the sensor INS, and periodic star observations under specific sequence, it is expected that the absolute attitude of an airborne IR sensor can be calibrated to within a small part of the instantaneous field of view of the sensor system.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133869187","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}
Multiple-access interference is a limiting factor in DS-CDMA. Since multiple-access noise is the sum of many independent random processes, it is reasonable to approximate it by a Gaussian process of the same power spectral density. This leads to the criterion of maximizing signal-to-noise ratio (SNR). In this paper, receivers that maximize SNR in a particular DS-CDMA system model under various constraints are proposed and analyzed. The method proposed here does not require locking and despreading multiple arriving CDMA signals. The performance of the system is analyzed when the receiver is constrained to operate bit-by-bit, in the absence of knowledge of the other users' spreading codes, timing, and phase.<>
{"title":"A noise-whitening approach to multiple-access noise rejection in a CDMA system","authors":"A. Monk, M. Davis, L. Milstein, C. Helstrom","doi":"10.1109/NTC.1994.316660","DOIUrl":"https://doi.org/10.1109/NTC.1994.316660","url":null,"abstract":"Multiple-access interference is a limiting factor in DS-CDMA. Since multiple-access noise is the sum of many independent random processes, it is reasonable to approximate it by a Gaussian process of the same power spectral density. This leads to the criterion of maximizing signal-to-noise ratio (SNR). In this paper, receivers that maximize SNR in a particular DS-CDMA system model under various constraints are proposed and analyzed. The method proposed here does not require locking and despreading multiple arriving CDMA signals. The performance of the system is analyzed when the receiver is constrained to operate bit-by-bit, in the absence of knowledge of the other users' spreading codes, timing, and phase.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131990031","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}
This paper introduces the concept of a digital channelized instantaneous frequency measurement receiver for electronic warfare applications. A technique to estimate the instantaneous frequency of two simultaneous signals in the same channel of the receiver is developed and the frequency estimation is compared to the Cramer-Rao bound.<>
{"title":"Digital channelized IFM receiver","authors":"T. W. Fields, D. Sharpin, J. Tsui","doi":"10.1109/NTC.1994.316686","DOIUrl":"https://doi.org/10.1109/NTC.1994.316686","url":null,"abstract":"This paper introduces the concept of a digital channelized instantaneous frequency measurement receiver for electronic warfare applications. A technique to estimate the instantaneous frequency of two simultaneous signals in the same channel of the receiver is developed and the frequency estimation is compared to the Cramer-Rao bound.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121159852","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}
'Infogeometrics' is the application of low unit cost, multimode digital/RF hardware and structured algorithm firmware that provide remotely maneuvering platforms with: (a) instrumentation quality location tracking, and (b) high bandwidth communications capability.<>
{"title":"An infogeometric approach to telerobotics","authors":"J. C. Harris","doi":"10.1109/NTC.1994.316670","DOIUrl":"https://doi.org/10.1109/NTC.1994.316670","url":null,"abstract":"'Infogeometrics' is the application of low unit cost, multimode digital/RF hardware and structured algorithm firmware that provide remotely maneuvering platforms with: (a) instrumentation quality location tracking, and (b) high bandwidth communications capability.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116367921","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 paper combines the tunnel-in-space methodology with a navigation and landing system requirements analysis to provide an integrated set of approach and landing requirements. The capabilities of the GPS system with various methods of augmentation are compared to the requirements to determine how far along the approach path a GPS-based system can be used as the principal navigation and landing aid. Once this is determined, the feasibility of augmenting the GPS with various forms of synthetic vision technology is examined. The result of this examination yields a set of recommended components for an integrated approach and landing system capable of meeting CAT III accuracy requirements.<>
{"title":"Methods for augmenting GPS for precision approach and landing","authors":"E. Koenke, J. Hill, P. Abramson","doi":"10.1109/NTC.1994.316663","DOIUrl":"https://doi.org/10.1109/NTC.1994.316663","url":null,"abstract":"The paper combines the tunnel-in-space methodology with a navigation and landing system requirements analysis to provide an integrated set of approach and landing requirements. The capabilities of the GPS system with various methods of augmentation are compared to the requirements to determine how far along the approach path a GPS-based system can be used as the principal navigation and landing aid. Once this is determined, the feasibility of augmenting the GPS with various forms of synthetic vision technology is examined. The result of this examination yields a set of recommended components for an integrated approach and landing system capable of meeting CAT III accuracy requirements.<<ETX>>","PeriodicalId":297184,"journal":{"name":"Proceedings of IEEE National Telesystems Conference - NTC '94","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122638812","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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