4 research outputs found

    ์ข์€ ํ™”๊ฐ์„ ๊ฐ–๋Š” ์ŠคํŠธ๋žฉ๋‹ค์šด ํƒ์ƒ‰๊ธฐ๋ฅผ ์œ„ํ•œ ์œ ๋„๊ธฐ๋ฒ•

    Get PDF
    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐยท์ปดํ“จํ„ฐ๊ณตํ•™๋ถ€, 2013. 8. ์ตœ์ง„์˜.New guidance laws are proposed to solve the problem of when a missile is equipped with a strapdown seeker instead of a gimbaled seeker. The strapdown seeker has advantages of relatively simple implementation compared to a gimbaled seeker, and it can eliminate frictional cross-coupling significantly save on costs. There have been many studies to enable guided missiles to use strapdown seekers, but they have several weaknesses, such as measurement error caused by scale factor error, radome errors, glint noise, narrow field-of-view (FOV), and so on. Among these weak points, focus is centered on the narrow FOV of the strapdown seeker. A hybrid guidance (HG) law is proposed to maintain the lock-on condition in spite of the narrow FOV of the strapdown seeker. The proposed HG law consists of two guidance phases, which assume operation at a switching boundary. In the first phase, the proportional navigation guidance (PNG) law is applied during the time when the look angle is inside the switching boundary. For the second phase, when the look angle is outside the switching boundary, a new guidance law is derived to keep the look angle within the FOV by employing a Lyapunov-like function based on sliding-mode control methodology. The appropriate determination of the switching boundary is an important issue. The idea behind selecting the switching boundary is to use the PNG law as much as possible, and to make the missile stay in the lock-on condition. A lock-on guidance (LOG) is proposed as another approach to solve the problem of narrow FOV, based on the concept of the pursuit guidance (PG) law. In order to derive the LOG law, we use a Lyapunov-like function based on the sliding-mode control methodology. An advantage of the LOG law is that a missile guided by the LOG law can intercept a target with a very narrow FOV of the strapdown seeker. Because such a seeker often has to be implemented for more accurate measurements, this kind of guidance law is needed to prepare for such a situation. The LOG law is simple and has good performance against a target with high speed.Abstract i Contents iii List of Figures vi List of Tables x Chapter 1. Introduction 1 1.1 Background and Motivations 1 1.2 Contents of the Research 6 Chapter 2. Preliminary Survey 10 2.1 Survey on Guidance Laws 10 2.1.1 Classical Guidance Laws 10 2.1.1.1 Pursuit Guidance Law 12 2.1.1.2 Constant Bearing Course Guidance Law 13 2.1.1.3 Line-of-Sight Guidance Law 13 2.1.1.4 Proportional Navigation Guidance Law 16 2.1.2 Modern Guidance Laws 23 2.1.2.1 Optimal-Control-Based Guidance Law 24 2.1.2.2 Predictive Guidance Law 27 2.1.2.3 Game-Theory-Based Guidance Law 30 2.1.2.4 Sliding-Mode-Control-Based Guidance Law 31 2.1.3 Summary 32 2.2 Survey on Missile Seekers 33 2.2.1 Gimbal Seeker 34 2.2.2 Strapdown Seeker 35 2.2.3 Summary 36 2.3 Remarks and Discussions 37 Chapter 3. The Proposed Guidance Laws 40 3.1 Hybrid Guidance Law 40 3.1.1 Problem Statement 41 3.1.2 The Overall Scheme 46 3.1.3 Guidance Law for the First Phase 48 3.1.4 Guidance Law for the Second Phase 48 3.1.5 Switching Boundary Estimation 50 3.2 Lock-on Guidance Law 56 3.2.1 Problem Statement 57 3.2.2 The Overall Scheme 62 3.2.3 Derivation 64 Chapter 4. Simulation Results 70 4.1 Hybrid Guidance Law 70 4.1.1 Non-maneuvering Target 70 4.1.2 Maneuvering Target 76 4.2 Lock-on Guidance Law 85 4.1.1 Non-maneuvering Target 85 4.1.2 Maneuvering Target 96 4.3 Comparison of Hybrid Guidance Law and Lock-on Guidance Law 105 Chapter 5. Conclusions 109 5.1 Concluding Remarks 109 5.2 Further Study 111 Bibliography 112 ๊ตญ๋ฌธ์ดˆ๋ก 123Docto

    The Research of the Space-Awareness Algorithm Based on Multi-Array Microsensors

    No full text
    The advances of MEMS (Micro Electromechanical Structures) technology have led the development of small-sized sensors (inertial sensors, magnetic compass sensors, acoustic sensors etc.). And we consider a digital signal processing sensor array system, based on randomly distributed sensor nodes, for some source localization applications. In this paper, we introduce the spaceawareness algorithm based on multi-array microsensors.ADD/MEM

    A Feasibility Study on Car Positioning system Using RFID

    No full text
    This paper shows a feasibility analysis results on RFID for car positioning system. Usually, a car navigation is mainly based on GPS combined with map-matching. However, in the case of poor visibility of satellites, GPS can not supply accurate position information continuously. In recent years, RFID has been considered to be one of key technologies in positioning and localization area. But its application and research results in the area of vehicular positioning are not popular. RFID system consists of tag, reader, antenna and software such as drivers and middleware. The main function of RFID system in a vehicular positioning is to retrieve 10 recorded position information from tags which set on the center of road. We propose a positioning method for vehicles using RFID and we present some indoor and outdoor experiment results to show that the proposed method is available in vehicle operational environments.๋ณธ ์—ฐ๊ตฌ๋Š” ํ•œ๊ตญ์ „์žํ†ต์‹ ์—ฐ๊ตฌ์›์—์„œ ์ง€์›ํ•˜๋Š” "RFID ๊ธฐ๋ฐ˜ ์ฐจ๋Ÿ‰ ์œ„์น˜์ •๋ณด ์„ผ์‹ฑ ๋ฐฉ๋ฒ• ๊ฒ€์ฆ ์—ฐ๊ตฌ" ๊ณผ์ œ์˜ ์˜ํ•˜์—ฌ ์—ฐ๊ตฌ๋˜์—ˆ์Œ

    Accurate Positioning of the Moving Vehicle Using RFID

    No full text
    Telematics is regarded as the technology to enhance and make everyday-driving experience more comfortable and safer. An essential part of the telematics is navigation and it is based on GPS combined with map-matching and/or MEMS DR as the choice of positioning technology. However, GPS cannot supply position information continuously in case of poor visibility of satellites. In this paper, we research into techniques of RFID which may be regarded as a portion of USN sensor node in order to measure accurate position information of vehicles regardless of environment condition. RFID tag recognition is tested to verify feasibility of accurate positioning according to the speed of vehicle. We also propose characteristics of the USN sensor node and data format for positioning.ETR
    corecore