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Performance Improvement Methods for Terrain Database Integrity

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Performance Improvement Methods for Terrain Database Integrity PERFORMANCE IMPROVEMENT METHODS FOR TERRAIN DATABASE INTEGRITY MONITORS AND TERRAIN REFERENCED NAVIGATION A thesis presented to the Faculty of the Fritz J. and Dolores H. Russ College of Engineering and Technology of Ohio University In partial fulfillment of the requirements for the degree Master of Science Ananth Kalyan Vadlamani March 2004 This thesis entitled PERFORMANCE IMPROVEMENT METHODS FOR TERRAIN DATABASE INTEGRITY MONITORS AND TERRAIN REFERENCED NAVIGATION BY ANANTH KALYAN VADLAMANI has been approved for the School of Electrical Engineering and Computer Science and the Russ College of Engineering and Technology by Maarten Uijt de Haag Assistant Professor of Electrical Engineering and Computer Science R. Dennis Irwin Dean, Russ College of Engineering and Technology VADLAMANI, ANANTH K. M.S. March 2004. Electrical Engineering and Computer Science Performance Improvement Methods for Terrain Database Integrity Monitors and Terrain Referenced Navigation (115pp.) Director of Thesis: Maarten Uijt de Haag Terrain database integrity monitors and terrain-referenced navigation systems are based on performing a comparison between stored terrain elevations with data from airborne sensors like radar altimeters, inertial measurement units, GPS receivers etc. This thesis introduces the concept of a spatial terrain database integrity monitor and discusses methods to improve its performance. Furthermore, this thesis discusses an improvement of the terrain-referenced aircraft position estimation for aircraft navigation using only the information from downward-looking sensors and terrain databases, and not the information from the inertial measurement unit. Vertical and horizontal failures of the terrain database are characterized. Time and frequency domain techniques such as the Kalman filter, the autocorrelation function and spectral estimation are designed to evaluate the performance of the proposed integrity monitor and position estimator performance using flight test data from Eagle/Vail, CO, Juneau, AK, Asheville, NC and Albany, OH. Approved: Maarten Uijt de Haag Assistant Professor of Electrical Engineering and Computer Science To my parents ACKNOWLEDGEMENTS During my study at Ohio University, I’ve worked on many projects, as part of the coursework under the guidance of my teachers, but none was as challenging or as extensive as this one: the Masters’ thesis. Challenging, because it led me to explore and understand concepts as an engineer and I wish to thank everyone who have helped me during the course of this research. I express my sincere thanks to my advisor, Dr. Maarten Uijt de Haag, who got me involved in research and encouraged me at every stage. Thank you Maarten, for your patience, attention and the faith that motivated me to go on. Also, for the numerous reviews and inputs, in the past for various conference papers and now for this thesis, which have helped to make this work meaningful. We have brought many a project to fruition and I’m sure we will continue to do so in future. I am grateful to my thesis committee members Dr. Michael Braasch, Dr. Frank van Graas and Dr. William (Gene) Kaufman for their time and effort in reviewing my thesis and their useful comments. I thank Dr. Braasch for the great learning experience during all the courses I took with him these last two and a half years that have contributed immensely to my understanding and my research. I thank Dr. van Graas for introducing and laying a solid foundation to the concepts that will remain with me throughout my career. I thank Jacob Campbell for a lot of things: patiently explaining his thesis to me, providing me with the data and some initial routines to work on, for the useful discussions that helped me burst through a plateau phase in my research, for his support and for simply being there, so I knew I could run up to him in case of problems. I thank Steve Young for his useful inputs during conferences and Dr. Robert Gray for his initial research that got it all started. I am thankful to the NASA B757 ARIES flight crew for their support and expertise during the EGE flight trials. I am deeply grateful to the Ohio University King-Air C90 pilots Brian Branham and Jamie Edwards for the flight tests at JNU, also to Dr. Richard McFarland for the flight tests at AVL and KUNI conducted on the Ohio University DC3 and the chief of airborne laboratories, Jay Clark, for his help and support during the said flight- testing. Support from the terrain database providers: NIMA, NGS, and Jeppesen is greatly appreciated. The research presented in this thesis was supported and funded through NASA under Cooperative Agreement NCC-1-3511. I thank the faculty, staff and all my colleagues at the Avionics Engineering Center who have all been part of this learning experience. In fact, I believe with all our interactions, I have learned as much in the break-room, hallways and student offices at AEC, as I have in formal coursework. It’s a great place with great people. I thank all my friends who have supported, tolerated, and motivated me, who have heard me out, who have set examples in all aspects of life and from whom I learn constantly. And most of all, I thank my parents, Ramanand and Kanaka Durga Vadlamani, for their love and encouragement and for making me the person I am. Although words cannot express my gratitude, I owe everything to them, my brother, Ravi, who has been there to share my joys and sorrows and my family who have constantly supported me. It is wonderful to be amongst you. 1 Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by NASA 7 TABLE OF CONTENTS Abstract...........................................................................................................................................3 Acknowledgements ........................................................................................................................5 List of Tables ..................................................................................................................................9 List of Figures...............................................................................................................................10 List of Acronyms..........................................................................................................................13 1 Introduction.........................................................................................................................15 1.1 Contributions ................................................................................................................16 1.2 Outline of the Thesis ....................................................................................................17 2 Synthetic Vision Systems ....................................................................................................18 2.1 SVS Component Description .......................................................................................21 2.1.1 Sensors.................................................................................................................22 2.1.2 Terrain Databases ...............................................................................................22 2.1.3 Displays ...............................................................................................................23 2.2 SVS Predecessors .........................................................................................................24 2.2.1 Ground Proximity Warning Systems (GPWS) .....................................................24 2.2.2 Terrain Awareness and Warning System (TAWS) ...............................................24 3 Terrain Database Integrity Monitor .................................................................................26 3.1 Statistical Method.........................................................................................................30 3.1.1 Formulation of Hypotheses..................................................................................31 3.1.2 Test Statistic for Decision Making.......................................................................33 3.1.3 Pseudo-Random Noise Analysis ..........................................................................36 3.2 Vertical Domain Integrity Monitor...............................................................................37 8 3.3 Horizontal Domain Integrity Monitor ..........................................................................38 3.4 Spatial Integrity Monitor ..............................................................................................41 4 Terrain Referenced Navigation..........................................................................................43 5 Theoretical Background .....................................................................................................52 5.1 The Kalman Filter.........................................................................................................55 5.1.1 Test Statistic Using Kalman Estimates ................................................................58 5.1.2 Pseudo-Random Noise Analysis Revisited...........................................................60 5.2 Autocorrelation Function Estimation ...........................................................................62 5.3 Modern Spectral Estimation .........................................................................................65 5.3.1 Blackman – Tukey Spectral
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