2008 Thurlow Award

Recipient: Dr. Todd Walter

Citation: For contributions to satellite navigation, including education, aviation applications and the mitigation of ionospheric effects.

Dr. Todd Walter is the Director of the Wide Area Augmentation System (WAAS) Laboratory at Stanford University. In this role, he has co-advised some 20 PhD students. Two of these students were the first and second winners of the ION’s Parkinson Award, and two students received the Jackson Award from the RTCA. For all students, Dr. Walter leads by the quality of his work, clarity of communication, and his intellectual generosity. Dr. Walter and his students have authored over 120 papers, and more than ten of these papers have received “Best Presentation” awards at ION GNSS conferences.

Dr. Walter has made important contributions to aviation safety by pioneering the development of space based augmentation systems (SBAS). The SBAS for North America is called the wide area augmentation system (WAAS), and Dr. Walter is central amongst those that enabled WAAS to become operational for aviation in July of 2003. Today, WAAS has over 40,000 airborne users and millions of non-aviation users.

In the 1990s, Dr. Walter led the development and implementation of an experimental prototype of the WAAS based on three West Coast reference stations. With these three stations, this system provided accuracy of better than two meters in real time, even when the aircraft was hundreds of miles from the nearest reference station. It was extended to provide similar accuracy on the challenging approach to Juneau Alaska.

Dr. Walter has emerged as an international leader on the safety analysis of satellite navigation systems. He was a pivotal member of the expert team that first analyzed the safety of WAAS. He developed many analyses to respond to the multiplicity of technical challenges and questions associated with this safety proof. He helped Japan certify their SBAS, and is well known for his active participation in RTCA and Eurocae on L5 development.

Dr. Walter is a world leader on the mitigation of ionospheric effects on satellite navigation. He is the lead designer of the ionospheric algorithm used by WAAS, and the originator of the dual time constant algorithm that will be utilized in Category II and III avionics based on the ground based augmentation system (GBAS). He revealed this idea in his landmark ION GPS 2000 paper entitled “Robust Detection of Ionospheric Irregularities.” Dr. Walter has served as the western regional vice president, Northern California section chair, ION Awards chair, ION GNSS 2007 general chair, ION GNSS 2006 program chair, ION NTM 2004 general chair, and ION NTM 2003 program chair. He is co-editor of the ION’s Red Book VI on WAAS.