DESIGN AND ANALYSIS OF TRANSFER ALIGNMENT ALGORITHMS A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY YİĞİTER YÜKSEL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ELECTRICAL AND ELECTRONICS ENGINEERING FEBRUARY 2005 i Approval of the Graduate School of Natural and Applied Sciences Prof. Dr. Canan Özgen Director I certify that this thesis satisfies all the requirements as a thesis for the degree of Master of Science. Prof. Dr. İsmet Erkmen Head of Department This is to certify that we have read this thesis and that in our opinion it is fully adequate, in scope and quality, as a thesis for the degree of Master of Science. Prof. Dr. Mübeccel Demirekler Supervisor Examining Committee Members Prof. Dr. Kemal Leblebicioğlu (Chairman), (METU, EE) Prof. Dr. Mübeccel Demirekler, (METU, EE) Prof. Dr. Aydan Erkmen, (METU, EE) Assist. Prof. Dr. Yakup Özkazanç, (Hacettepe Unv., EE) Dr. Ayşe Pınar Koyaz, (TÜBİTAK – SAGE) ii I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Yiğiter YÜKSEL iii ABSTRACT DESIGN AND ANALYSIS OF TRANSFER ALIGNMENT ALGORITHMS YÜKSEL, Yiğiter M.S., Department of Electrical and Electronics Engineering Supervisor : Prof. Dr. Mübeccel Demirekler February 2005, 169 Pages Transfer Alignment is the process of simultaneously initializing and calibrating a weapon inertial navigation system (INS) using data from host aircraft’s navigation system. In general, this process is accomplished by calculating the difference of navigation solutions between aircraft and weapon INSs to form observations which are then used in a Kalman filter to generate desired estimates. Numerous techniques about the problem of transfer alignment exist in the literature. In this thesis, those techniques that can be applied in the presence of elastic motion of aircraft wing were analyzed. Several transfer alignment algorithms each of which process different measurement types were designed and implemented. In order to evaluate the performance of implemented algorithms under realistic conditions, a transfer alignment simulation environment was developed. Using this simulation environment, the advantages and disadvantages of each algorithm were analyzed and the dependence of transfer alignment performance on Kalman filter system model, aircraft maneuvers and alignment duration were investigated. Keywords: Transfer Alignment, In-motion Alignment, Inertial Navigation iv ÖZ YÖNELİM AKTARIMI ALGORİTMALARININ TASARIM VE ANALİZİ YÜKSEL, Yiğiter Yüksek Lisans., Elektrik ve Elektronik Mühendisliği Bölümü Tez Yöneticisi : Prof. Dr. Mübeccel Demirekler Şubat 2005, 169 Sayfa Yönelim aktarımı, uçağın seyrüsefer sistemi çıktılarını kullanarak mühimmat üzerindeki ataletsel seyrüsefer sistemine ilk değer atama ve sistemin kalibrasyonunun eş zamanlı yapılması işlemidir. Genel olarak bu işlem, uçağın ve mühimmatın seyrüsefer sonuçları arasındaki farktan bir ölçüm oluşturulması ve bu ölçümün Kalman süzgecinde işlenmesiyle gerçekleştirilir. Konuyla ilgili kaynaklarda, aktarım yönlendirme ile ilgili birçok teknik ortaya konmuştur. Bu tezde, uçak kanadının elastiki hareketinin mevcut olduğu durumlarda uygulanabilecek aktarım yönlendirme teknikleri incelenmiştir. Farklı ölçüm çeşitlerini işleyebilen birçok Kalman filtresi tasarlanmıştır. Tasarlanan Kalman filtrelerinin performanslarını gerçekçi bir ortamda sınayabilmek için, bir yönelim aktarımı benzetim ortamı geliştirilmiştir. Geliştirilen benzetim ortamı kullanılarak, her bir yönelim aktarımı algoritmasının başarımı analiz edilmiş ve Kalman filtresi sistem ve ölçüm modeli, uçak manevrası ve algoritma uygulama süresinin yönelim aktarımı algoritmaları performansı üzerindeki etkileri incelenmiştir. Anahtar Kelimeler: Yönelim Aktarımı, Ataletsel Seyrüsefer, Hareket Halinde İlklendirme v To my mother and father who still love me despite of my endless peevishness. vi ACKNOWLEGMENTS I am greatly thankful to my supervisor Prof. Dr. Mübeccel Demirekler for her guidance throughout the preparation of this thesis. Thanks to her advices and appreciated criticisms, I had the chance of improving my studies. I am also grateful to Uğur Topay, Burak Kaygısız, Yüksel Subaşı and Ayhan Erdim for their help and friendship during this period. I would like to express my sincere thanks to my family for their support and understanding. Finally, I would like to thank my brother. Even his sole existence makes me feel more confident. TÜBİTAK-SAGE who supported this work is greatly acknowledged. vii TABLE OF CONTENTS ABSTRACT...........................................................................................................iv ÖZ...........................................................................................................................v ACKNOWLEGMENTS..........................................................................................vii TABLE OF CONTENTS.......................................................................................viii LIST OF SYMBOLS...............................................................................................xi LIST OF ABBREVATIONS...................................................................................xv 1 INTRODUCTION.................................................................................................1 1.1 Thesis Objectives...............................................................................4 1.2 Organizatıon of the Thesis.................................................................5 2 INERTIAL NAVIGATION SYSTEM.....................................................................7 2.1 Slave Navigation System Structure...................................................8 2.2 Navigation System Errors................................................................10 2.2.1 Slave IMU Errors...................................................................11 2.2.2 Initialization Errors.................................................................13 2.2.3 Computational Errors............................................................14 2.3 Navigatıon System Error Analysis...................................................15 2.3.1 Linear Error Propagation Models..........................................15 2.3.1.1 Attitude Error Propagation...............................................15 2.3.1.2 Velocity Error Propagation..............................................16 2.3.1.3 Position Error Propagation..............................................17 2.3.2 Verification of Linear Error Propagation Models...................17 3 KINEMATICS OF MASTER AND SLAVE SYSTEMS AND CHARACTERIZATION OF VIBRATION ENVIRONMENT...................................21 3.1 Trajectory Generation......................................................................22 3.1.1 Trajectory Regeneration Function.........................................24 3.1.2 Trajectory Shaping Function.................................................28 3.1.2.1 Level Flight......................................................................29 3.1.2.2 Vertical Turn....................................................................29 3.1.2.3 Coordinated Turn............................................................29 3.2 KINEMATIC RELATIONS BETWEEN MASTER AND SLAVE........34 viii 3.2.1 Velocity Relation...................................................................34 3.2.2 Attitude Relation....................................................................36 3.2.3 Acceleration Relation............................................................37 3.2.4 Rotation Rate Relation..........................................................37 3.2.5 Position Relation...................................................................38 3.3 Characterization of Vibration Environment......................................38 3.4 Analysis of Vibration Dependent Errors...........................................42 4 DESIGN OF TRANSFER ALIGNMENT ALGORITHMS....................................44 4.1 Introduction......................................................................................44 4.2 Transfer Alıgnment Simulation Environment....................................48 4.3 Acceleration / Rotation Rate Matching Method................................53 4.4 Velocity Matching Method................................................................63 4.5 Integrated Velocity Mathcing Method...............................................68 4.6 Attitude Matching Method................................................................83 4.7 Velocity and Attitude Matching Method............................................95 5 ANALYSIS OF TRANSFER ALIGNMENT ALGORITHMS BASED ON VELOCITY OBSERVATIONS............................................................................108 5.1 Comparision of Velocity and Integrated Velocity Matching Methods 109 5.2 Effect of Kalman Filter Update Rate..............................................119 5.3 Effect of Aircraft Maneuvers on Kalman Filter Estimates...............126 6 CONCLUSIONS & FUTURE WORKS.............................................................143 6.1 Recommended Future Works........................................................144 REFERENCES...................................................................................................147 APPENDICES A SUMMARY OF CONING AND SCULLING ALGORITHMS............................150 A.1 Coning Algorithm...........................................................................150 A.2 Sculling Algorithm..........................................................................155 A.3 Total Algorithm Error under General Motion..................................158 B VIBRATION MODELS.....................................................................................161 B.1 X Axes Linear Vibration Model.......................................................162 B.2 Y Axes Linear Vibration Model.......................................................163 B.3 Z Axes Linear Vibration Model.......................................................163 B.4 Roll Axes Rotational Vibration Model.............................................165 ix B.5 Pitch & Yaw Axes Rotational Vibration Model................................166 C KALMAN FILTER STRUCTURE USED IN TRANSFER ALIGNMENT ALGORITHMS....................................................................................................168 x
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