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1.
Giulio L. Marco B. Aldo F. Domenico T.P. Mario M. 《Aerospace and Electronic Systems Magazine, IEEE》2002,17(9):22-27
This paper reviews the results of the thermal and static analysis of small motor aerospace technology (SMART) propulsion system, constituted of a microthrusters array realised by MEMS technology on silicon wafers. This system has been studied using FEM (NASTRAN) and the results have been verified by the electro-thermic analogy and the FDM method, using, respectively, SPICE and MATLAB codes. The simulation results demonstrated the feasibility of SMART systems for aerospace applications such as attitude control and deorbiting missions for small satellite station-keeping. A theoretical impulse of 20 mNs has been calculated for the SMART system. 相似文献
2.
Snyder S. Schipper B. Vallot L. Parker N. Spitzer C. 《Aerospace and Electronic Systems Magazine, IEEE》1992,7(5):3-11
In November 1990, a differential GPS/inertial flight test was conducted to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS/INS with barometric and radar altimeters. Flight test results obtained from postflight data analysis are presented. These results include characteristics of DGPS/inertial error, using a laser tracker as a reference. In addition, data are provided on the magnitude of the differential correlations and vertical channel performance with and without radar altimeter augmentation. Flight test results show one sigma DGPS/inertial horizontal errors of 9 ft and one sigma DGPS inertial vertical errors of 15 ft. Without selective availability effects, the differential corrections are less than 10 ft and are dominated by receiver unique errors over the time period of an approach. Therefore, the one sigma performance of the autonomous GPS (8-ft horizontal and 20-ft vertical) is very similar to the DGPS/inertial performance. Postprocessed results also demonstrate significant improvements in vertical channel performance when GPS/inertial is aided with radar altimeter along with a low-resolution terrain map 相似文献
3.
Significant advances in and applications of battery technology are outlined. Factors driving future developments are identified 相似文献
4.
5.
P.L. Israelevich A.I. Ershkovich 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,17(12):99-103
Plasma and magnetic field disturbances accompanying dust particle impacts are explained by means of creation of a secondary cloud around the spacecraft. Cold cometary ions impinging upon the cloud are scattered by atoms of the cloud. This scattering changes initial angular distribution of cometary ions. Magnetic field perturbation is created by the friction between the electron component of the cometary plasma flow and the cloud. 相似文献
6.
Rogers S.K. Ruck D.W. Kabrisky M. Tarr G.L. 《Aerospace and Electronic Systems Magazine, IEEE》1990,5(9):17-19
A brief summary of research done at the Air Force Institute of Technology (AFIT) in the area of neural networks is provided. It has been shown that backpropagation, used for feedforward artificial neural networks, is just a degenerate version of an extended Kalman filter, and that networks can do about as well as the optimum statistical classification technique. A method of finding the importance of features for use by a neural network classifier has been determined. Techniques for using neural networks for image segmentation have been developed. In optical pattern recognition, techniques that allow the processing of real FLIR (forward-looking infrared) images with existing binary spatial light modulators have been devised. An optical direction of arrival detector applicable to laser illumination direction determination has been designed and tested; the design is similar to a fly's eye. Coated mirrors for the optical confocal Fabry-Perot interferometer have been designed, specified, fabricated, and installed. Significant progress has been made in the use of neural networks for processing multiple-feature sets for speech recognition 相似文献
7.
Lenz R. Schuler K. Younis M. Wiesbeck W. 《Aerospace and Electronic Systems Magazine, IEEE》2006,21(5):30-33
In April 2006, the TerraSAR-X satellite was launched. This paper describes the development of a novel and highly integrated, digitally-controlled active SAR system calibrator (DARC). It consists of both an active transponder path for absolute radiometric calibration and a calibrated receiver chain for antenna pattern evaluation of the satellite antenna. A total of 16 active transponder and receiver systems and 17 receiver-only systems will be fabricated for a calibration campaign in 2006. 相似文献
8.
The James Webb Space Telescope (JWST) project at the NASA, Goddard Space Flight Center (GSFC) is responsible for the development, launch, flight, and science operations for the telescope. The project is in phase B with its launch scheduled for no earlier than June 2013. The project is a partnership among NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The JWST mission team is fully in place, including major ESA and CSA subcontractors. This provides an overview of the planned JWST science, current architecture focusing on the instrumentation, and mission status, including technology developments, and risks. 相似文献
9.
Garenaux K. Merlet T. Alouini M. Lopez J. Vodjdani N. Boula-Picard R. Fourdin C. Chazelas J. 《Aerospace and Electronic Systems Magazine, IEEE》2007,22(2):3-8
Radar systems require transmission of very high purity signals. Photonics is now mature enough to achieve analog transmission with very low noise, strong immunity, and wide-bandwidth even in harsh environments. We present our recent developments of optimized optical links dedicated to radar and multifunction systems 相似文献
10.
The US Department of Defense (DoD), through the Office of the Secretary of Defense (OSD), has determined that evolutionary acquisition is their strategy of choice for future software-intensive systems, and that the spiral development model (SDM) is the preferred method/process for software-intensive development life cycles. Electronic Systems Command (ESC) at Hanscom AFB, Massachusetts, has written a draft handbook on the use of Spiral Development for all future Command and Control (C2) systems, including reference to the DoD 5000 series and Air Force Program Directive 63-1, Acquisition System, which deploys this OSD mandate for future C2 systems. Barry Boehm's continued work on SDM which he conceived in the 1980s, is heavily biased toward development of new systems that are software-intensive, as noted in a workshop he gave at the Software Engineering Institute (SEI) in 2000. 相似文献