排序方式: 共有18条查询结果,搜索用时 109 毫秒
11.
Pace P.E. Nash M.D. Zulaica D.P. Di Mattesa A.A. Hosmer A. 《IEEE transactions on aerospace and electronic systems》2001,37(3):810-823
Captive-carry electronic warfare (EW) tests evaluate the response of hardware-in-the-loop (HIL) missile seekers to an actual environment (test-range) including the presence of electronic attack. This paper describes a relative targeting architecture that displays the test-range results in geodetic coordinates using only the sensors available on board the captive-carry platform (GPS, INS, seekers). To derive the target position in geodetic coordinates, a lever-arm correction process is described that determines the position of each seeker and the corresponding pitch and yaw of the simulator. Combining the positional parameters of the seeker with its targeting variables, the seeker track point is displayed in geodetic coordinates, A track tagging algorithm is presented to identify the true target from the EW disruption using the drift angle from the inertial navigation system (INS), To eliminate the scintillation noise present in the track image, a Kalman filter in sensor coordinates is applied to the targeting variables allowing optimization of the track tagging. Experimental results from a recent EW field test using antiship cruise missile simulators are shown to demonstrate the feasibility of the approach for determining EW effectiveness in near real-time. Targeting accuracy is also quantified by comparing the derived target position with the true Global Positioning System (GPS) test-range position of the ship in the absence of electronic attack 相似文献
12.
R. Pacione B. Pace H. Vedel S. de Haan R. Lanotte F. Vespe 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
In this article we present two methods for combination of different Global Navigation Satellite Systems (GNSS) Zenith Total Delay (ZTD) time-series for the same GNSS site, but from different producers or different processing setups. One method has been setup at ASI/CGS, the other at KNMI. Using Near Real-Time (NRT) ZTD data covering 1 year from the E-GVAP project, the performance of the two methods is inter-compared and validation is made against a combined ZTD solution from EUREF, based on post-processed ZTDs. Further, validation of the ASI combined solutions is made against independent ZTDs derived from radiosonde, Numerical Weather Prediction (NWP) model and Very Long Baseline Interferometry (VLBI) ZTD. 相似文献
13.
For a successful enemy maneuver, their most important action is the ability to identify, locate, and track their correct target. High-resolution imaging sensors such as the inverse synthetic aperture radar perform this action in the most effective way and are especially useful against low radar cross-section targets. Once the correct target is acquired and identified, the decision to engage is made and the weapons are selected. Counter-targeting is the attempt to prevent (or degrade) the engage-and-launch-weapons decision by the enemy. This paper describes an all-digital image synthesizer technique capable of generating realistic false-target images for counter-targeting using modern digital radio frequency memory technology. Uses in counter-lock on for coherent seekers in the terminal mode are also discussed. Examples of the output false target image capability are presented. 相似文献
14.
Scott Pace 《Space Policy》2011,27(3):127-130
China has engaged in a steady, long-standing effort to build and strengthen its space capabilities, achieving progressively more ambitious milestones and staking its claim as a major space power. It is also increasingly engaging in cooperative efforts. A number of issues must be weighed, however, before the USA should consider any collaboration with it. These include the essentially military nature of China’s space program, the fact that China’s intentions in space and decision-making process are far from ‘transparent’, and the way it uses its space activities to pursue foreign policy goals. While the latter could be useful in, e.g., reducing tensions on the Korean peninsular through a space-services-for-giving-up-missiles tradeoff, and while there is scope for collaboration in space science missions, there are no compelling reasons for the USA to pursue cooperation in human spaceflight with China. 相似文献
15.
Emanuele A. Slejko Anna Gregorio Vanni Lughi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(5):1468-1476
The increasing number of commercial, technological and scientific missions for CubeSats poses several concerns about the topic of space junk and debris mitigation. As no regulation is currently in place, innovative solutions are needed to mitigate the impact that Low Earth Orbit objects can have during uncontrolled re-entry and the associated potential events of surface collision. We investigated the requirements, in terms of materials selection, for the development of a 3D-printed structural bus able to withstand loads during launch and in-orbit operations, with the objectives to be as light as possible and requiring the least amount of heat for demise during atmospheric re-entry. The selection indicated magnesium alloys as the best candidates to improve the reference material, aluminium 6061 T6, resulting in both mass-reduction and improved demisability. We also analysed how the relative importance of these two objectives can modify the selection of materials: if minimizing the heat to disintegration were valued more highly than lightness, for example, the new best candidates would become tin alloys. Our analysis, furthermore, suggested the importance of Liquid Crystal Polymer as the sole plastic material approaching the performance of the best metal choices. This contribution, thus, provides novel insight in the field of 3D-printed materials for the fast-growing CubeSat segment, complying with the debris mitigation initiatives promoted by space agencies and institutions. 相似文献
16.
Scott Pace 《Space Policy》1988,4(4):307-318
The new US administration faces complex questions on the future role of the USA in space, and tough decisions on how to pay for it. Decisions made now on space transportation will have a strong impact on US space leadership for the next decade. The author discusses the history and current state of space transportation planning, and considers the key issues which will confront the new administration. 相似文献
17.
E. Marsch E. Antonucci P. Bochsler J. -L. Bougeret B. Fleck R. Harrison Y. Langevin R. Marsden O. Pace R. Schwenn J. -C. Vial 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2002,29(12):135-2040
The scientific rationale of the Solar Orbiter is to provide, at high spatial (35 km pixel size) and temporal resolution, observations of the solar atmosphere and unexplored inner heliosphere. Novel observations will be made in the almost heliosynchronous segments of the orbits at heliocentric distances near 45 R and out of the ecliptic plane at the highest heliographic latitudes of 30° – 38°. The Solar Orbiter will achieve its wide-ranging aims with a suite of sophisticated instruments through an innovative design of the orbit. The first near-Sun interplanetary measurements together with concurrent remote observations of the Sun will permit us to determine and understand, through correlative studies, the characteristics of the solar wind and energetic particles in close linkage with the plasma and radiation conditions in their source regions on the Sun. Over extended periods the Solar Orbiter will deliver the first images of the polar regions and the side of the Sun invisible from the Earth. 相似文献
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