Seamless Precise Positioning through the Integration of Satellite, Terrestrial Ranging and Inertial Technologies By Wei Jiang A thesis in fulfilment of the requirements for the Degree of Doctor of Philosophy School of Civil and Environmental Engineering Faculty of Engineering UNSW Sydney NSW 2052, Australia June, 2015 ABSTRACT The integration of Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) technologies is a very useful navigation option for high accuracy positioning in support of many applications, including airborne mapping, urban positioning and sensor georeferencing. An integrated GNSS/INS system provides navigation solutions by taking advantage of the complementary characteristics of each component technology. However its performance is still limited by the quality of GNSS measurements (when available) and the geometric configuration of the visible satellites. To address this limitation, an alternative, non-GNSS-based positioning technology can augment the traditional integrated GNSS/INS multi-sensor system. Locata is a terrestrial-based technology which can transmit GNSS-like ranging signals. This research is focused on the integration of GNSS, Locata and INS technologies so as to provide accurate and reliable navigation coverage. The main research contributions are: (a) An “on-the-fly” (OTF) Locata resolution algorithm that takes advantage of geometry change via an Extended Kalman filter is proposed. Single-differenced Locata carrier phase measurements are utilised for accurate and reliable solutions. A “loosely-coupled” decentralised Locata/INS integration architecture based on the Kalman filter is used for data processing. To evaluate the performance of the proposed system a field trial was conducted on Sydney Harbour. The experiment demonstrated that the Locata OTF algorithm was effective and could improve the system accuracy in comparison with the conventional “known point initialisation” method. Furthermore, the experiment confirmed that Locata/INS integration could achieve centimetre-level accuracy for position solutions, and centimetre-per-second accuracy for velocity determination. (b) A new Precise Point Positioning (PPP) technique, augmented by Locata measurements is proposed. In the Locata-augmented PPP-GNSS approach the Locata and GNSS carrier phase measurements are processed simultaneously in a “tightly-combined” mode, and the carrier phase ambiguities are resolved as floating- point values on an epoch-by-epoch basis. A field experiment indicated that the initial convergence time of the integrated Locata/GNSS filter was only 10 seconds, which was significantly faster than using the conventional PPP-GNSS algorithm. I Abstract Moreover, the proposed Locata-augmented PPP-GNSS technique could achieve centimetre-level accuracy for horizontal positioning, which was superior to both the Locata-only and PPP-GNSS techniques. (c) A “loosely-coupled” integration algorithm scheme for PPP-GNSS, Locata and INS is developed. To satisfy both accuracy and reliability requirements, three integration algorithms – Centralised Kalman filtering, Federated Kalman filtering and Global Optimal filtering (GOF) – are investigated and implemented within a “triple- integrated” GNSS/Locata/INS navigation system. A preliminary performance assessment, based on the analysis of real data, concluded that all three integration algorithms were able to achieve positioning solutions at centimetre-level accuracy. (d) A novel adaptive fault-tolerant multi-sensor integrated navigation system is proposed, which can ensure a reliable positioning service in complex situations. The proposed system implements a decentralised filtering architecture to fuse the INS, GNSS and Locata measurements. In order to improve the system accuracy, the GOF algorithm is used to implement the proposed multi-sensor navigation system. The adaptive technique is based on the innovation covariance discrepancy, which mainly adapts to the changes in the statistical properties of the sensor measurements, and mitigates the adverse influence caused by these changes. To evaluate the fault- tolerance capability of the proposed system, a series of typical GNSS failures were simulated. The results confirmed that the proposed system was not affected by the failures, and that the reliability and fault tolerant capability were improved. (e) Locata technology could not only be used in outdoor environments as a GNSS “augmentation”, it also can enable precise indoor navigation. In this research, a new multipath mitigating antenna “V-Ray” developed by Locata Corporation is used to address the challenges of making terrestrial ranging measurements in an indoor environment with severe multipath. A new navigation methodology – the position and attitude modelling system (PAMS) – is proposed for processing carrier phase and azimuth measurements via an Unscented Kalman filter. The PAMS can output the complete set of navigation parameters – position, velocity, acceleration and attitude – simultaneously via an OTF initialisation. The indoor test was conducted in a metal warehouse and the results confirmed that the horizontal positioning solution had an accuracy of better than 5cm and an orientation accuracy of better than 0.7 degrees. II ACKNOWLEDGEMENT I would like to gratefully acknowledge the enthusiastic supervision of Professor Chris Rizos during this work. His help, support, and guidance from initial step to the final level enabled me to complete this work. I am also deeply grateful to my co-supervisor Dr. Yong Li for his invaluable help. His knowledge and experience have been a tremendous help for me during my PhD period. Sincere thanks to Associate Professor Samsung Lim, Dr. Binghao Li and Dr. Alex NG for reviewing my work each year and providing me with constructive feedback. I would like to acknowledge to China Scholarship Council (CSC) and the University of New South Wale (UNSW) for awarding me research scholarship and allowing me to enjoy this challenging but extremely interesting research work. I also would like to express my thanks to all the other staff members, especially Associate Dr. Mohammad Choudhury, Dr. Craig Roberts, and Professor Jinling Wang for their valuable advice on my research and their continuous encouragements. Special thanks to Dr. Joel Barnes, Dr. Steve Hewitson, Dr. David Small and Mr. Nunzio Gambale from Locata Company for their tremendous help in terms of Locata technology and field experiments. Thanks are also given to visiting academic staff, particular Associate Professor Liangqing Lu from National University of Defense Technology and Associate Professor Gongmin Yan from Northwestern Polytechnical University. I am also thankful to Dr. Tao Li, Dr. Ling Yang, Dr. Sara Shirowzhan, Dr. Wei Li, Dr. Yiping Jiang, Mr. Yang Yang, Mr. Zeyu Li, Ms. Liran Sun and Mr. You Shao for their years of friendship. Last, but far from least, I would like to express my deepest appreciation to my family. Sincere gratitude is given to my father Sizhe Jiang and my mother Yanqiong Cao, for their unconditional love, understanding, and support which motivated me on my PhD journey. A special thanks and much love to my husband, Kaibin Zong, for his love and consideration for the four years, and keep me smiling and energetic all the time. III TABLE OF CONTENTS ABSTRACT ....................................................................................................................... I ACKNOWLEDGEMENT .............................................................................................. III TABLE OF CONTENTS ................................................................................................ IV LIST OF FIGURES ..................................................................................................... VIII LIST OF TABLES .......................................................................................................... XI CHAPTER 1 ..................................................................................................................... 1 INTRODUCTION ............................................................................................................ 1 1.1 Background ........................................................................................................ 1 1.2 Research Motivation and Objective ................................................................... 3 1.3 Contributions of the Research ............................................................................ 5 1.4 Thesis Outline ..................................................................................................... 7 1.5 List of Publications ............................................................................................. 9 1.5.1 Peer-reviewed Journal Publications ................................................................. 9 1.5.2 Full Paper Peer-reviewed Conference Publications ......................................... 9 1.5.3 Abstract Reviewed Conference Publications ................................................. 10 CHAPTER 2 ................................................................................................................... 11 REVIEW THE GEO-REFERENCING TECHNOLOGIES AND NAVIGATION ALGORITHMS .............................................................................................................. 11 2.1 Overview of GNSS Positioning Technology ........................................................ 11 2.1.1 GNSS Introduction ........................................................................................