Performance of a Doppler-aided GPS navigation system for aviation applications under ionospheric scintillation

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 scintillation. To validate the designed GPS receiver, a GPS channel model for aircraft landing in equatorial regions is built based on the use of high fidelity GPS constellation simulator, clock emulator, and real ionosphere interfered with GPS data collected in an equatorial region. The results of this research demonstrate that the integration of a GPS receiver with a low-cost inertial navigation system provides the capability to operate continuously during the periods of strong scintillation. In addition, so-called vector processing also shows promise for less severe scintillation environment. Various combinations of receiver tracking architectures and aiding methods have been conducted to quantify the sensitivity improvement of an "aided" GPS receiver.