共查询到20条相似文献,搜索用时 171 毫秒
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针对模块化设计中的方案设计阶段讨论了模块的特性,在此基础上提出了模块创建的策略,并讨论了模块创建策略的实现方法.基于这种方法构建了模块创建子系统,并用实例说明了模块创建的过程. 相似文献
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时序控制模块做为某雷达数据处理机的核心模块,为雷达整机提供各种定时信号,同时还提供与TV显示处理机、指挥仪、敌我识别器等的交联信号.文章详细介绍了采用超大规模集成电路设计时序控制模块的方法. 相似文献
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本文介绍了基于组、角色的模块控制思想,在多层(MIDAS)结构下,对程序模块访问进行控制的一种通用机制。通过对组、角色的权限分配和模块配置,最终达到系统操作人员的权限限制和模块访问控制,是应用程序授权的基础。 相似文献
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时序控制模块为某雷达数据处理机的核心模块,为雷达整机提供各种定时信号,同时还提供与TV显示处理机、指挥仪、敌我识别器等的交联信号。文章详细介绍邓采用超大规模集成电路设计时序控制模块的方法。 相似文献
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Rotation method for direction finding via GPS carrier phases 总被引:2,自引:0,他引:2
Peng H.M. Chang E.R. Wang L.S. 《IEEE transactions on aerospace and electronic systems》2000,36(1):72-84
A baseline rotation method is proposed for determining the direction of the baseline vector via Global Positioning System (GPS) carrier phase measurements. The space difference technique is adopted to resolve GPS carrier phase cycle ambiguities. Possible applications include the determination of the aiming directions of artillery rockets and the line of sights of tracking radars, etc. For such armaments, the direction findings are important and the rotating mechanisms are well equipped already. A general baseline vector which can be rotated on a two-degree-of-freedom platform is considered first. The relationship among the baseline vector and the two rotation axes is not known. A sequence of rotations is used to change the configuration of the system to find the direction of the baseline. Under different circumstances such as the cases that some orthogonal conditions among the unknown vectors are given, simplified algorithms are devised. To verify our method, software simulation and hardware experiments have been conducted. The simulation outcomes are used to determine the experimental parameters, such as the length of the baseline, the rotation angles etc. The results of repeated hardware experiments show that the sample standard deviation for the azimuth angle and the elevation angle of the 1.35 m baseline vector are 0.91 deg and 1.23 deg, respectively. The GPS receivers employed are Motorola ONCOREs. The errors of the estimated direction angles induced by the inaccuracy of rotation angles, which are unavoidable due to the imperfectness of the mechanical structure, are analyzed as well. Numerical examples for the error analysis are included 相似文献
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The Global Positioning System (GPS) is a satellite navigation system capable of providing 15-m position accuracy. Its system time reference is currently one of the monitor station clocks. Using a simple two-clock example, it is shown analytically that improved reference time stability and overall state estimation accuracy can be achieved by constructing GPS time as an ensemble of all system clocks and that the problem of covariance divergence can be handled by the introduction of pseudomeasurement processing 相似文献
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A method to apply the latest technology in Global Navigation Satellite Systems (GNSS), in particular the U.S. NAVSTAR GPS (NAVigation System for Timing And Ranging Global Positioning System) and the Russian GLONASS (GLObal'naya Nqvigatsionnaya Sputnikovaya Sistema), as a silent multistatic or parasitic radar for air defense is described. These satellite systems serving as navigational aids are well suited for low power radar applications due to the similarity and compatibility of the transmitted satellite signals with modern radar signals, such as spread spectrum modulation and Pseudo Random Noise (PRN) codes. Preliminary flight tests with airships, jet and propeller aircraft, helicopter, anti tank missiles and spaceborne targets (MIR) to study effects have been conducted 相似文献
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《Air & Space Europe》1999,1(2):68-71
In terms of land users of the US Global Positioning System (GPS), the Japanese market is the most mature in the world. As such, it provides the ‘blueprint’ for how mass markets in other developed countries will respond to GPS and, in the future, to the second generation Global Navigation Satellite System (GNSS-2). The information which follows draws on a recent report prepared by Logica for the UK government, and highlights the growth of the in-car navigation market in Japan and the various technologies being used. 相似文献
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An Extended Kalman Filter (EKF) is commonly used to fuse raw Global Navigation Satellite System (GNSS) measurements and Inertial Navigation System (INS) derived measurements. However, the Conventional EKF (CEKF) suffers the problem for which the uncertainty of the statistical properties to dynamic and measurement models will degrade the performance. In this research, an Adaptive Interacting Multiple Model (AIMM) filter is developed to enhance performance. The soft-switching property of Interacting Multiple Model (IMM) algorithm allows the adaptation between two levels of process noise, namely lower and upper bounds of the process noise. In particular, the Sage adaptive filtering is applied to adapt the measurement covariance on line. In addition, a classified measurement update strategy is utilized, which updates the pseudorange and Doppler observations sequentially. A field experiment was conducted to validate the proposed algorithm, the pseudorange and Doppler observations from Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS) were post-processed in differential mode. The results indicate that decimeter-level positioning accuracy is achievable with AIMM for GPS/INS and GPS/BDS/INS configurations, and the position accuracy is improved by 35.8%, 34.3% and 33.9% for north, east and height components, respectively, compared to the CEKF counterpart for GPS/BDS/INS. Degraded performance for BDS/INS is obtained due to the lower precision of BDS pseudorange observations. 相似文献
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This paper describes the development of a low-cost and small size integrated Global Positioning System (GPS)/inertial measurement unit (IMU). The developed strapdown Attitude and Heading Reference System (AHRS) is capable of providing attitude and heading accuracy at ±0.2 and ±0.4 degrees, respectively. The prototype of low-cost integrated GPS/IMU can give positioning accuracy of 10 metres 相似文献
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《Aerospace and Electronic Systems Magazine, IEEE》1998,13(11):41-46
Development of a new vehicle avionics suite is described, including integration of a low-cost, tightly-coupled integrated Inertial Navigation System/Global Positioning System (INS/GPS) to support vehicle guidance, navigation, and control (GN&C). A wide variety of next-generation low-cost launch vehicles could potentially benefit from integrated INS/GPS technology for GN&C and/or range safety applications. Coleman Aerospace Company (CAC) has developed a new low-cost avionics suite, the generic Integrated Mission Guidance & Tracking System (IMGTS), an open architecture, modular system that supports the requirements for various guidance applications and range safety tracking. As part of this development, Boeing North American, Inc. is supplying its Modular Miniature Integrated GPS/INS Tactical System (M-MIGITSTM) Military-Off-The-Shelf (MOTS) INS/GPS product to support CAC's IMGTS GN&C 相似文献
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GLONASS (Global Orbiting Navigation Satellite System) is the most recent satellite navigation system developed by the Soviet Union and currently in the pre-operational stage. Obvious parallels exist between GLONASS and the NAVSTAR Global Positioning System (GPS) developed in the United States and also, at present, in a pre-operational phase. In the progress towards operational status, the launch capability for NAVSTAR satellites has been seriously affected by the recent failure of the Space Shuttle Challenger, clearly increasing the prospects of GLONASS reaching operational status first. It is therefore the main purpose of this paper to discuss certain aspects of the GLONASS satellite navigation system, in particular its orbital features and radio-frequency signal characteristics. Comparisons with NAVSTAR are inevitable and for this reason, the paper begins with a brief resume of relevant features of the NAVSTAR GPS system for later reference. The main section of the paper then deals with orbital behaviour, radio frequency signal structure and channelisation using NAVSTAR as a reference point for discussion. 相似文献
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