2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)最新文献

{"title":"Estimation of sea surface temperature using the AVHRR mid-wave IR band","authors":"Jennifer C. Davis, Jerry X. Tu, Sean P. Byme James, Lisowski, SciTec","doi":"10.1109/AERO.2001.931513","DOIUrl":"https://doi.org/10.1109/AERO.2001.931513","url":null,"abstract":"We describe a method for estimating sea surface temperature (SST) using MWIR band data from the AVHRR polar orbiter. Currently, SST is routinely calculated with a split-window, nonlinear multichannel algorithm incorporating data from AVHRR Channels 4 and 5 (10.3-11.3 and 11.5-12.5 /spl mu/m, respectively). The accuracy of these results is dependent to a certain degree upon regional variations and is inherently limited by the spatial resolution of the measurements. Nevertheless, these SST maps are generally considered reliable, and are widely used for studying ocean currents and their effect on weather patterns. We are interested, however, in testing the feasibility of using MWIR data in the absence of LWIR measurements for estimating SST both at night, when reflected solar radiance is not an issue, as well as during the day, when it is. A MWIR SST algorithm of the type we discuss would be using data, for example, from a satellite without LWIR capabilities in order to calculate a parameter that is ancillary to the satellite mission (but which is nevertheless of high interest). The SST algorithms we describe are based upon the comparison of MODTRAN ocean radiance values, at a variety of surface temperatures and calculated over the aforementioned AVHRR bands, to the values of the collected pixels in these bands. These MODTRAN calculations are scene-specific, as viewing angle and atmospheric conditions are important input parameters. MODTRAN is therefore launched from within the main SST program architecture for a range of different temperatures. The results of such calculations could conceivably be implemented, however, as a look-up table for a grid of LZAs, standard atmospheres and temperatures. Before the temperature of the pixels can be assessed, the scene must be screened for clouds, which tend to lower the temperature estimation for contaminated pixels. We accomplish this screening using our CloudDI algorithm, a modified least squares template-matching approach. Finally, we test the validity of our results against the AVHRR SST algorithms as well as against available ground truth. Since the MODTRAN calculations require sensor geometry and atmospheric conditions as input parameters, it is possible, in theory, to correct for the effect of high levels of water vapor on the SST results in certain situations.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124962077","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}

{"title":"Dimpled ball grid array qualification testing for space flight applications","authors":"S. Barr, A. Mehta","doi":"10.1109/AERO.2001.931198","DOIUrl":"https://doi.org/10.1109/AERO.2001.931198","url":null,"abstract":"With smaller and smaller Printed Wiring Board (PWB) form factors, such as CompactPCI/sup (R)/, the need for smaller packages with high I/Os has grown significantly. A Jet Propulsion Laboratory/NASA technology and system development program that services various spacecraft missions uses a 3U CompactPC/sup (R)/ form factor. The System Input/Output board requires a large amount of I/Os and has limited area, so conventional packages, such as quad flat packs (QFP) will not fit. Thus, the use of Ball Grid Arrays (BGAs) with much smaller package dimensions than leaded packages were needed to meet area requirements and were evaluated for space flight applications. Since this type of package has not been used in past space flight environments, it was necessary to determine the robustness and reliability of the solder joints. The D-BGAs were qualified by developing assembly, inspection and rework techniques as well as environmental tests. The test article was a printed wiring assembly (PWA) consisting of four daisy chained D-BGA packages. Visual inspection of the outer solder joints and real time X-ray were used to verify solder quality prior to testing. The test article was electrically monitored for shorts and opens at or above 1 /spl mu/s during all environmental tests. Three environmental tests were conducted: random vibration at 0.2 g/sup 2//Hz, pyre shock at 2000 g for 50 ms, and thermal cycling from -55/spl deg/C to 100/spl deg/C for 200 cycles. After testing, Scanning Electron Microscope (SEM) analysis was performed on various DBGA cross sections to determine the quality of the package-to-board interface. The 472 D-BGA solder attachments passed the above environmental tests meeting the minimum requirements for use on space flight electronics.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128030886","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}

{"title":"The engine air-start test of XF-2","authors":"J. Miyano","doi":"10.1109/AERO.2001.931225","DOIUrl":"https://doi.org/10.1109/AERO.2001.931225","url":null,"abstract":"The engine air-start test program was carried out as one of the flight tests for the XF-2, Japanese next generation support fighter. The objective of the program was to demonstrate the aircraft's capability to recover from in-flight engine shutdown. The XF-2 being a single engine aircraft, this is one of major requirements to the aircraft. The planning and results of the tests are described. Tests were planned with emphasis on the safe execution because the engine is shut down during the flight tests. In all air-start conditions tested the air-start succeeded without exceeding the criteria; the time to ignition, the time to thrust recovery and the maximum exhaust gas temperature, and it was confirmed that the aircraft is capable to recover from in-flight engine shutdown.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131141007","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}

{"title":"Generalized cross-signal anomaly detection on aircraft hydraulic system","authors":"R. Mackey","doi":"10.1109/AERO.2001.931245","DOIUrl":"https://doi.org/10.1109/AERO.2001.931245","url":null,"abstract":"This paper outlines the mathematical foundation for a general method of anomaly detection from time-correlated sensor data. This method is a component of BEAM, but as an individual algorithm is capable of fault detection and partial classification. The method is applicable to a broad class of problems and is designed to respond to any departure from normal operation, including faults or events that lie outside the training envelope. We will also consider training of the detector and interface to a larger diagnostic system. Lastly we examine a brief illustration taken from aircraft testing that demonstrates the power and versatility of this method.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131263285","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}

{"title":"Efficient data fusion for multi-sensor management","authors":"Marcel L. Hernandez","doi":"10.1109/AERO.2001.931172","DOIUrl":"https://doi.org/10.1109/AERO.2001.931172","url":null,"abstract":"This paper is concerned with the development of a general framework for the management of multiple sensors in tracking a single target. To achieve this aim we draw on concepts from data fusion, particle filtering and heuristic optimization. Previous work gave the multi-sensor fusion management algorithm which provided a rigid scheme under which sensors were placed to maximize the probability of detecting the target. We present an adaptation to this scheme in which sensor placements are chosen to minimize a measure of uncertainty in the target position. We demonstrate the algorithm in an anti-submarine warfare scenario in which we use passive sonobuoys to generate bearings and frequency (Doppler) data, We show that the quality of the track increases dramatically with the combined use of the two data sources and that the new sensor management algorithm further improves the track, and uses significantly fewer sensors in the process.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127795245","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}

{"title":"Performance comparison of multipath mitigating receiver architectures","authors":"M. Braasch","doi":"10.1109/AERO.2001.931361","DOIUrl":"https://doi.org/10.1109/AERO.2001.931361","url":null,"abstract":"As the Global Positioning System (GPS) has matured over the last decade, expectations regarding system performance have grown steadily. This has placed pressure on receiver manufacturers and system providers to be ever more creative in their efforts to mitigate error sources. Historically, multipath has been the dominant error source in differential GPS (DGPS). However, with the recent decision to deactivate Selective Availability, multipath has become a significant error source for all GPS users. In 1991, the narrow correlator was introduced to the market and was shown to reduce multipath errors by as much as 90% over conventional receivers. Over the past several years, a number of multipath-mitigation techniques have been developed and promoted. This paper explores the theory behind each technique and provides a performance comparison. The inherent assumptions and limitations of each technique are discussed as well.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133051161","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}

{"title":"Approximate CFAR signal detection low rank non-Gaussian interference","authors":"I. Kirsteins, M. Rangaswamy","doi":"10.1109/AERO.2001.931489","DOIUrl":"https://doi.org/10.1109/AERO.2001.931489","url":null,"abstract":"We have derived a new generalized likelihood ratio test for detecting a signal in unknown, strong non-Gaussian low rank interference plus white Gaussian noise. An important advantage of the new test is that it needs essentially no knowledge of the non-Gaussian distribution, except that the coherent part of the interference is or can be approximated as low rank. Using perturbation expansions of the test statistic, we establish the connection of the proposed GLRT detector to the UMPI test and show that it is approximately CFAR. Computer simulations indicate that the new detector significantly outperforms traditional adaptive methods in non-Gaussian interference and is insensitive to signal and rank mismatch.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114699996","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}

{"title":"An improved PMHT using an idea from coding","authors":"Y. Ruan, P. Willett","doi":"10.1109/AERO.2001.931506","DOIUrl":"https://doi.org/10.1109/AERO.2001.931506","url":null,"abstract":"Tracking is inherently a combinatorial optimization problem under the (admittedly realistic) constraint that each target generates at most one measurement per scan per sensor. Practical algorithms to solve the combinatorial problem are usually intelligent suboptimal procedures. Optimal procedures can be derived if the constraint above is relaxed. The PMHT (probabilistic multi-hypothesis tracker) uses \"soft\" posterior-probability associations between measurements and targets. Its implementation is a straightforward iterative application of the Kalman smoother operating on \"synthetic\" (i.e., modified) measurements, and of recalculation of these synthetic measurements based on the current track estimate. As applied to data fusion the PMHT is a very natural procedure, in that complexity is generally linear in the number of sensors. In this presentation, we first discuss the basic PMHT and some of the older PMHT variants which have been used to enhance convergence. We then treat a new turbo-PMHT, which is informed by the recent success of turbo coding in communication contexts. This new PMHT has performance substantially improved versus any of the previous versions, and generally as good as the probabilistic data association filter.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115468884","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}

{"title":"High-temperature superconductor-magnet momentum wheel for micro satellite","authors":"Eunjeong Lee, Jang-Horng Yu, T. L. Wilson","doi":"10.1109/AERO.2001.931207","DOIUrl":"https://doi.org/10.1109/AERO.2001.931207","url":null,"abstract":"We have constructed a superconductor-magnet momentum wheel, which is based on passive magnetic levitation and the flux pinning effect of high-temperature superconductivity. The high-temperature superconductor (HTS) flywheel has high angular momentum storage capacity because its drag torque is essentially velocity-independent and extremely small, enabling high-speed rotation. It has mass of 1.1 kg with an angular momentum capacity of 3.5 J sec. It occupies a volume of 12.7 cm in diameter and 5 cm in height. It operates within the restricted power budget of a micro satellite with a total power supply of 10 W only. It consumes less than 1 W for sustenance. While there exist momentum wheels comparable to ours in one respect, there is none better than ours in all respects of angular momentum storage, volume and low power consumption.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"477 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123054364","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}

{"title":"IR sounder technology trends","authors":"C. Schueler","doi":"10.1109/AERO.2001.931469","DOIUrl":"https://doi.org/10.1109/AERO.2001.931469","url":null,"abstract":"Advanced IR sounding benefits partly from cloud-top parameter and surface emissivity estimates, using coincident imaging spectroradiometry. While a separate imager on the same spacecraft on which the sounder is located can provide closely coincident surface and cloud parameter estimates, an \"imaging sounder\" that can deliver image and sounding data may reduce cost. Key technology trends enabling low-risk \"imaging sounders\" include better and lower cost optics, improved spectral-separation, low-noise wide bandwidth large area focal plane arrays, reliable active cooling, and low-power, higher density electronics for high-rate analog-to-digital conversion and on-board data processing. Trends over the last decade and efforts underway are identified with improvements anticipated in the next decade. Applications are described with reference to instrumentation either in-orbit or under development.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123634907","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}