An Improved Ionosphere Scintillation Event Detection and Automatic Trigger for A GNSS Data Collection System Steve Taylor, Yu Morton, Yu Jiao, Jeffrey Triplett, Miami University Wouter Pelgrum, Ohio University BIOGRAPHY Steve Taylor is a master degree student in the Department of Electrical and Computer Engineering at Miami University. He received his BS in Computer Science from Miami University in 2011. Dr. Yu (Jade) Morton is a Professor of Electrical Engineering at Miami University of Ohio. Her research interests are advanced GNSS receivers, ionospheric effects on GPS performance, and non-GPS RF navigation sensors. She received her PhD in electrical engineering from the Pennsylvania State University. Yu Jiao is a masters degree student in the Department of Electrical and Computer Engineering. She received her bachelor’s degree in Electrical Engineering from Beihang University, China in 2011. Jeffrey Tripplet is an IT network manager in the School of Engineering and Applied Science and a part-time master degree student in Computer Science at Miami University. He received his BS in Electrical Engineering from Miami University in 2007. Wouter Pelgrum is an Assistant Professor of Electrical Engineering at Ohio University where he researches and teaches electronic navigation-related topics, such as GNSS, DME, Loran, Time and Frequency transfer. Before joining Ohio University in 2009, he worked in private industry where he contributed to the development of an integrated GPS-eLoran receiver and antenna. From 2006 until 2008 he operated his own company, specializing in navigation-related research and consulting. ABSTRACT Ionosphere scintillations impact the performance of GNSS receivers. To gain a better understanding of how scintillations affect GNSS signals, a GNSS receiver array has been established at Gakona, Alaska to collect scintillation data. Collection of continuous raw IF samples is prohibitive because of the large amount of data involved. An autonomous data collection system is needed to record data only when there are scintillation activities. Recently, we developed a number of scintillation event threshold triggers for the GNSS receiver array using low rate outputs from a commercial receiver. When the indicator surpasses the threshold, the system will declare that there is a scintillation event and data collected by RF frontend sampling devices are then recorded to storage for later processing and analysis. Overly conservative triggers lead to a large number of missed detections whereas overly aggressive triggers result in large number of false alarms. This paper presents an improved scintillation event trigger based upon a detailed analysis of the commercial receiver data collected at the GNSS array site. 1. INTRODUCTION As we enter a new solar maximum period, GNSS receivers, especially those operating in high latitude and equatorial regions, face an increased threat of interference from ionosphere scintillations. The increased solar activities, however, also offer a great opportunity to collect scintillation data to gain a better understanding of how scintillations alter or affect GNSS signal parameters. Such an understanding is essential for researchers to develop receiver processing algorithms that are more robust under ionosphere scintillation conditions and for scientists studying the ionosphere. Collection of continuous raw IF samples is prohibitive because of the large amount of data involved. A typical narrowband front end with a 5MHz sampling frequency and 4-bit resolution ADC generates 2.5MB data per second or 9GB per hour. To study scintillation effects on wideband signals, such GPS L5, this rate will go up by a factor of 10. For tomography studies where an array of receivers is used, the storage will further increase by the size of the array. Therefore, it is important to have a “smart” data collection system that will only record data when there is scintillation activity. For this purpose, low-rate outputs International Technical Meeting (ITM) of The Institute of Navigation, Newport Beach, CA, January 30 February 1, 2012 1563