Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187151
K. Sampigethaya, R. Poovendran
Future airspace systems are complex in the types of manned and unmanned aircraft and in managing a massive number of these airborne payload containers. Cyber - a highly intangible mix of networking, software, storage, and computing - is vital for superior performance of aircraft and airspace systems. Performance risks, however, emerge from evolving dynamics and unpredictability of an adverse operational environment, both in cyberspace and physical world. This paper proposes a novel cyber-physical system (CPS) framework for aircraft and airspace system design and performance assurance. We present the foundational role of the e-enabled aircraft in the worldwide air transport system modernization. We show how automated air navigation and surveillance depend on tight integration and controlled coordination between in-aircraft systems and off-board systems in ground, air, and space. Based on our seminal concept of “group flight,” we propose a fundamental CPS solution for controlling large volumes of manned and unmanned air traffic using Automatic Dependent Surveillance Broadcast (ADS-B) and Internet Protocol (IP) technology.
{"title":"Cyber-physical system framework for future aircraft and air traffic control","authors":"K. Sampigethaya, R. Poovendran","doi":"10.1109/AERO.2012.6187151","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187151","url":null,"abstract":"Future airspace systems are complex in the types of manned and unmanned aircraft and in managing a massive number of these airborne payload containers. Cyber - a highly intangible mix of networking, software, storage, and computing - is vital for superior performance of aircraft and airspace systems. Performance risks, however, emerge from evolving dynamics and unpredictability of an adverse operational environment, both in cyberspace and physical world. This paper proposes a novel cyber-physical system (CPS) framework for aircraft and airspace system design and performance assurance. We present the foundational role of the e-enabled aircraft in the worldwide air transport system modernization. We show how automated air navigation and surveillance depend on tight integration and controlled coordination between in-aircraft systems and off-board systems in ground, air, and space. Based on our seminal concept of “group flight,” we propose a fundamental CPS solution for controlling large volumes of manned and unmanned air traffic using Automatic Dependent Surveillance Broadcast (ADS-B) and Internet Protocol (IP) technology.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"31 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81499590","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187201
M. Grabbe, J. W. McDerment, A. P. Douglas
This paper develops a batch processing algorithm that can be used to track a constant velocity surface target. The purpose of this algorithm is to facilitate passive tracking when sensor-target geometry is poor, which can prevent the convergence of a recursive estimator. The target's position is considered to be the output of an ordinary differential equation having unknown parameters to be estimated. This contrasts with the model used for the design of recursive estimators such as a Kalman filter where the target's position is the output of a dynamic system driven by white noise. Batch processing of all sensor measurements and Iterated Least-Squares (ILS) are used to estimate the target model parameters. Numerical integration is used to propagate the target's position and the Jacobian needed by ILS. Simulation results are shown for a maritime surveillance mission.
{"title":"A batch processing algorithm for moving surface target tracking","authors":"M. Grabbe, J. W. McDerment, A. P. Douglas","doi":"10.1109/AERO.2012.6187201","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187201","url":null,"abstract":"This paper develops a batch processing algorithm that can be used to track a constant velocity surface target. The purpose of this algorithm is to facilitate passive tracking when sensor-target geometry is poor, which can prevent the convergence of a recursive estimator. The target's position is considered to be the output of an ordinary differential equation having unknown parameters to be estimated. This contrasts with the model used for the design of recursive estimators such as a Kalman filter where the target's position is the output of a dynamic system driven by white noise. Batch processing of all sensor measurements and Iterated Least-Squares (ILS) are used to estimate the target model parameters. Numerical integration is used to propagate the target's position and the Jacobian needed by ILS. Simulation results are shown for a maritime surveillance mission.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"19 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81827613","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187423
K. Wortman
This paper discusses management of the independent acceptance test activity in a space domain software development cycle. The goal of acceptance test is to independently verify functional software requirements to achieve a high level of confidence in the software system before release for operational use. Key management areas have been identified through internal independent acceptance test practice at Johns Hopkins University Applied Physics Laboratory for NASA's Radiation Belt Storm Probes software system. The key management areas have been categorized as People, Constraints, Needs and Quality (PCNQ). The supporting framework for management of the PCNQ factors encompasses the established lines and means of communications for the project, and the organizational culture. The PCNQ areas and their relationships must be strategically managed within the framework for an effective independent acceptance test of a spacecraft's mission software system. The concepts presented in this paper will promote understanding of the management role of an independent software acceptance test activity in the space domain.
{"title":"Management of independent software acceptance test in the space domain: A practitioner's view","authors":"K. Wortman","doi":"10.1109/AERO.2012.6187423","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187423","url":null,"abstract":"This paper discusses management of the independent acceptance test activity in a space domain software development cycle. The goal of acceptance test is to independently verify functional software requirements to achieve a high level of confidence in the software system before release for operational use. Key management areas have been identified through internal independent acceptance test practice at Johns Hopkins University Applied Physics Laboratory for NASA's Radiation Belt Storm Probes software system. The key management areas have been categorized as People, Constraints, Needs and Quality (PCNQ). The supporting framework for management of the PCNQ factors encompasses the established lines and means of communications for the project, and the organizational culture. The PCNQ areas and their relationships must be strategically managed within the framework for an effective independent acceptance test of a spacecraft's mission software system. The concepts presented in this paper will promote understanding of the management role of an independent software acceptance test activity in the space domain.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"5 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81874154","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187055
G. Kakani, P. Jesudhasan, S. Pillai
Planetary and sample return missions require surface cleaning procedures using biocides. However, a deep understanding of how microorganisms respond to biocides is needed. The response of different Salmonella serovars to defined concentrations of chlorine, chlorine dioxide, and cetylpyridinium chloride (CPC) was studied. Microbial responses in terms of culturability, and virulence gene expression were also evaluated. Inactivation when exposed to chlorine and CPC was extremely rapid. Inactivation due to chlorine dioxide was, however, gradual. Exposure to these biocides caused a number of physiological states in Salmonella cells including dormancy, injury, and a viable but non-culturable state. Based on real-time PCR assays, all virulence-related genes were down-regulated in the presence of chlorine, chlorine dioxide and CPC. These studies highlight the importance of understanding the possible responses of organisms to biocides before they are used in mission critical applications such as pre-flight cleaning and laboratory protocols involved in sample return missions.
{"title":"Different biocides elicit differential responses in bacteria","authors":"G. Kakani, P. Jesudhasan, S. Pillai","doi":"10.1109/AERO.2012.6187055","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187055","url":null,"abstract":"Planetary and sample return missions require surface cleaning procedures using biocides. However, a deep understanding of how microorganisms respond to biocides is needed. The response of different Salmonella serovars to defined concentrations of chlorine, chlorine dioxide, and cetylpyridinium chloride (CPC) was studied. Microbial responses in terms of culturability, and virulence gene expression were also evaluated. Inactivation when exposed to chlorine and CPC was extremely rapid. Inactivation due to chlorine dioxide was, however, gradual. Exposure to these biocides caused a number of physiological states in Salmonella cells including dormancy, injury, and a viable but non-culturable state. Based on real-time PCR assays, all virulence-related genes were down-regulated in the presence of chlorine, chlorine dioxide and CPC. These studies highlight the importance of understanding the possible responses of organisms to biocides before they are used in mission critical applications such as pre-flight cleaning and laboratory protocols involved in sample return missions.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"37 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81935099","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187085
J. Hoffman, L. Del Castillo, D. Hunter, J. Miller
The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires improvements in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and are now being implemented side-by-side with more standard technology typically used in flight hardware.
{"title":"Robust, rework-able thermal electronic packaging: Applications in high power TR modules for space","authors":"J. Hoffman, L. Del Castillo, D. Hunter, J. Miller","doi":"10.1109/AERO.2012.6187085","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187085","url":null,"abstract":"The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires improvements in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and are now being implemented side-by-side with more standard technology typically used in flight hardware.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"5 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84244309","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187084
J. Hoffman, D. Perkovic, S. Shaffer, L. Veilleux, E. Peral
Real-time digital beamforming, combined with lightweight, large aperture reflectors, enable a new architecture, which is the baseline for the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI). This new instrument concept requires new methods for calibrating multiple simultaneous channels. The calibration of current state-of-the-art Electronically Steered Arrays typically involves pre-flight TR (Transmit/Receive) module characterization over temperature, and in-flight correction based on measured temperatures. This method ignores the effects of element aging and any drifts unrelated to temperature. We are developing new digital calibration of digital beamforming arrays, which helps to reduce development time, risk and cost. Precision calibrated TR modules enable real-time beamforming architectures by accurately tracking modules' characteristics through closed-loop digital calibration, which tracks systematic changes regardless of temperature. The benefit of this effort is that it would enable a new, lightweight radar architecture, with on-board digital beamforming. This provides significantly larger swath coverage than conventional SAR architectures for solid earth and biomass remote sensing, while reducing mission mass and cost.
{"title":"Digital calibration of TR modules for real-time digital beamforming SweepSAR architectures","authors":"J. Hoffman, D. Perkovic, S. Shaffer, L. Veilleux, E. Peral","doi":"10.1109/AERO.2012.6187084","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187084","url":null,"abstract":"Real-time digital beamforming, combined with lightweight, large aperture reflectors, enable a new architecture, which is the baseline for the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI). This new instrument concept requires new methods for calibrating multiple simultaneous channels. The calibration of current state-of-the-art Electronically Steered Arrays typically involves pre-flight TR (Transmit/Receive) module characterization over temperature, and in-flight correction based on measured temperatures. This method ignores the effects of element aging and any drifts unrelated to temperature. We are developing new digital calibration of digital beamforming arrays, which helps to reduce development time, risk and cost. Precision calibrated TR modules enable real-time beamforming architectures by accurately tracking modules' characteristics through closed-loop digital calibration, which tracks systematic changes regardless of temperature. The benefit of this effort is that it would enable a new, lightweight radar architecture, with on-board digital beamforming. This provides significantly larger swath coverage than conventional SAR architectures for solid earth and biomass remote sensing, while reducing mission mass and cost.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"30 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84341095","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187135
J. Kreng, M. Ardeshiri
Many parameters can affect the range correlation and range measurement during a spacecraft's normal range operation as well as in a space vehicle range testing environment. These parameters include the unanticipated voltage standing wave ratio (VSWR) reflection, multipath, flutter, space or hardware group delay, and ionospheric propagation delay, which can distort the amplitude and phase of the received pseudorange noise (PRN) range signal. Many other known or deterministic parameters, such as range receiver average noise - from local oscillator (LO) and quantization average noises, and Doppler delay, can be removed a priori from the range calculation by using software. This paper deals with correlation of the PRN range code in the correlation receiver relative to the 500 kHz clock in the reference clock receiver. This paper shows that this range correlation value (RCV) could well exceed the known correlation limit of 100% due to the unexpected VSWR reflection, multipath, or space or hardware delay, as mentioned above.
{"title":"Effects of unanticipated VSWR reflection and delay on range correlation performance","authors":"J. Kreng, M. Ardeshiri","doi":"10.1109/AERO.2012.6187135","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187135","url":null,"abstract":"Many parameters can affect the range correlation and range measurement during a spacecraft's normal range operation as well as in a space vehicle range testing environment. These parameters include the unanticipated voltage standing wave ratio (VSWR) reflection, multipath, flutter, space or hardware group delay, and ionospheric propagation delay, which can distort the amplitude and phase of the received pseudorange noise (PRN) range signal. Many other known or deterministic parameters, such as range receiver average noise - from local oscillator (LO) and quantization average noises, and Doppler delay, can be removed a priori from the range calculation by using software. This paper deals with correlation of the PRN range code in the correlation receiver relative to the 500 kHz clock in the reference clock receiver. This paper shows that this range correlation value (RCV) could well exceed the known correlation limit of 100% due to the unexpected VSWR reflection, multipath, or space or hardware delay, as mentioned above.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"30 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85001508","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187056
Wolfgang Fink, Markus Tuller, Alexander D. Jacobs, Ramaprasad Kulkarni, M. Tarbell, R. Furfaro, Victor R. Baker
We introduce a robotic lake lander test bed that can be operated either stand-alone or as part of a Tier-Scalable Reconnaissance mission architecture to study and field test an integrated hardware and software framework for fully autonomous surface and subsurface exploration and navigation of liquid bodies. The lake lander is equipped with both surface and subsurface sensor technologies. Our particular focus is on Saturn's moon Titan with its hydrocarbon lakes with respect to future missions involving lake landers (e.g., Titan Mare Explorer (TiME) mission), potentially in conjunction with balloons/airships and orbiter-support overhead. This test bed serves as an analog to a Titan unpiloted surface vessel equipped with its own onboard realtime navigation and hazard avoidance system, surface and subsurface exploration sensor suite, and autonomous science investigation software system. As such the test bed helps map out a technical path toward true autonomy for the robotic exploration of the Solar System.
{"title":"Robotic lake lander test bed for autonomous surface and subsurface exploration of Titan lakes","authors":"Wolfgang Fink, Markus Tuller, Alexander D. Jacobs, Ramaprasad Kulkarni, M. Tarbell, R. Furfaro, Victor R. Baker","doi":"10.1109/AERO.2012.6187056","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187056","url":null,"abstract":"We introduce a robotic lake lander test bed that can be operated either stand-alone or as part of a Tier-Scalable Reconnaissance mission architecture to study and field test an integrated hardware and software framework for fully autonomous surface and subsurface exploration and navigation of liquid bodies. The lake lander is equipped with both surface and subsurface sensor technologies. Our particular focus is on Saturn's moon Titan with its hydrocarbon lakes with respect to future missions involving lake landers (e.g., Titan Mare Explorer (TiME) mission), potentially in conjunction with balloons/airships and orbiter-support overhead. This test bed serves as an analog to a Titan unpiloted surface vessel equipped with its own onboard realtime navigation and hazard avoidance system, surface and subsurface exploration sensor suite, and autonomous science investigation software system. As such the test bed helps map out a technical path toward true autonomy for the robotic exploration of the Solar System.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"11 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85239964","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187280
T. Clark, L. Young, K. Duda, C. Oman
Planetary landing requires the selection of a suitable landing zone followed by a stable, controlled descent to the surface. In crewed landings, astronauts are expected to play an active role in hazard identification, landing point selection, vehicle navigation, and supervision of automated systems. However, astronauts will have experienced sensorimotor adaptation during their microgravity exposure and may face unique landing conditions which could lead to inaccurate perceptions of vehicle orientation. A quantitative model of visual-vestibular integration was used to predict astronaut perceptions of vehicle orientation during various planetary landing trajectories, including altered gravity levels. The model predicted the potential for disorientation during specific portions of the landing trajectories when visual cues were not available. Astronaut spatial disorientation is also a concern for commercial crew, particularly as the number of landings increases. Our methodology allows for the early identification of trajectories or motions which may result in disorientation.
{"title":"Simulation of astronaut perception of vehicle orientation during planetary landing trajectories","authors":"T. Clark, L. Young, K. Duda, C. Oman","doi":"10.1109/AERO.2012.6187280","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187280","url":null,"abstract":"Planetary landing requires the selection of a suitable landing zone followed by a stable, controlled descent to the surface. In crewed landings, astronauts are expected to play an active role in hazard identification, landing point selection, vehicle navigation, and supervision of automated systems. However, astronauts will have experienced sensorimotor adaptation during their microgravity exposure and may face unique landing conditions which could lead to inaccurate perceptions of vehicle orientation. A quantitative model of visual-vestibular integration was used to predict astronaut perceptions of vehicle orientation during various planetary landing trajectories, including altered gravity levels. The model predicted the potential for disorientation during specific portions of the landing trajectories when visual cues were not available. Astronaut spatial disorientation is also a concern for commercial crew, particularly as the number of landings increases. Our methodology allows for the early identification of trajectories or motions which may result in disorientation.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"48 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85462945","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 : 2012-03-03DOI: 10.1109/AERO.2012.6187143
N. Adams, W. Millard, D. Copeland
Receiver tracking loops are implemented in software in modern space-borne radios. Software implementation allows loop designs to be modified in flight. Not only filter coefficients and gain, but also loop order and type can be modified. This flexibility enables new cognitive and autonomous capabilities. Loop designs can be optimized for each mission phase, and separate loops can be used for acquisition and tracking. Furthermore, the loops can be automatically adapted based on changing signal dynamics or SNR. However, if the loop has tracked away from its quiescent state, the loop will lose lock when the switch occurs unless the internal state of the loop is translated appropriately. This paper considers the internal state of feedback tracking loops. In particular, a physical interpretation of loop state is derived that enables translating the loop state from one design to another. Limitations to autonomous switching, including high-order signal states and noise, are described, and several examples are simulated. Practical applications for both near-earth and deep-space missions are discussed.
{"title":"Autonomous loop switching: Interpreting and modifying the internal state of feedback tracking loops","authors":"N. Adams, W. Millard, D. Copeland","doi":"10.1109/AERO.2012.6187143","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187143","url":null,"abstract":"Receiver tracking loops are implemented in software in modern space-borne radios. Software implementation allows loop designs to be modified in flight. Not only filter coefficients and gain, but also loop order and type can be modified. This flexibility enables new cognitive and autonomous capabilities. Loop designs can be optimized for each mission phase, and separate loops can be used for acquisition and tracking. Furthermore, the loops can be automatically adapted based on changing signal dynamics or SNR. However, if the loop has tracked away from its quiescent state, the loop will lose lock when the switch occurs unless the internal state of the loop is translated appropriately. This paper considers the internal state of feedback tracking loops. In particular, a physical interpretation of loop state is derived that enables translating the loop state from one design to another. Limitations to autonomous switching, including high-order signal states and noise, are described, and several examples are simulated. Practical applications for both near-earth and deep-space missions are discussed.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"54 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80863666","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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