Tsung-Yu Chiou

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Deep and frequent GPS signal fading due to strong ionospheric scintillation is major concern for aircraft navigation in the equatorial region during solar maximum periods. Deep signal fading can break a receiver’s carrier tracking lock on a satellite channel and the satellite cannot be used for position solution until a receiver reacquires the lost channel.(More)
Aircraft navigation based on GPS (Global Positioning System) and WAAS (Wide Area Augmentation System) requires both code and carrier measurements to calculate the position estimate [1]. A GPS receiver’s carrier tracking loop is weaker than code tracking loop. Thus, carrier lock can more easily be broken under deep signal fading caused by ionospheric(More)
The Phase-Locked Loop (PLL) is a key component of modern electronic communication and control systems. PLL is designed to extract signals from transmission channels. It plays an important role in systems where it is required to estimate the phase of a received signal, such as carrier tracking from global positioning system satellites. In order to robustly(More)
Ionospheric scintillation has a significant impact on the availability of Global Positioning System (GPS) and Wide Area Augmentation System (WAAS), especially when the GPS/WAAS receiver is dynamically stressed. An example of such a scenario would be an aircraft using WAAS to make an approach and landing. This study investigated the tolerable wideband(More)
The ionosphere has practical importance in GPS (Global Positioning System) applications because it influences transionospheric radio wave propagation. Among various phenomena in the ionosphere, ionospheric scintillation is characterized by rapid fluctuation and fading of the received signal intensity due to electron density irregularity inside the(More)
The Joint Precision Approach and Landing System (JPALS) is the next generation aircraft precision approach and landing system being sponsored by US Department of Defense. This GPS-based system will provide joint operational capability for military users to perform assigned conventional and special operations missions from fixed-base, tactical, shipboard,(More)
The Phase-Locked Loop(PLL) is a key component of modern electronic communication and control systems. PLL is designed to extract signals from transmission channels. It plays an important role in systems where it is required to estimate the phase of a received signal, such as carrier tracking from global positioning system (GPS) satellites. In order to(More)
Aircraft landing using the Global Positioning System (GPS) in equatorial regions is more difficult than in other regions because ionospheric scintillation is prevalent. Ionospheric scintillation causes amplitude fades of 20 dB or more and an increase in the phase jitter. This research evaluates techniques to enhance a GPS receiver for overcoming ionospheric(More)