Global navigation satellite system (GNSS) is essential to aviation communication navigation surveillance and air traffic management A continuous accurate positioning service allows a GNSS-supported surveillance system to keep up with the growing requirements of civil aviation However many studies have shown that GNSS signals are susceptible to interference To continue accurate positioning service in the case of GNSS failure various alternative positioning navigation and timing (APNT) systems have been proposed The objectives of APNT systems are to provide navigation and surveillance services to ensure flight safety when GNSS fails In the first part of this thesis the wide area multilateration (WAM) mechanism for APNT systems is developed using commercial off-the-shelf components and a city-size multilateration experiment is carried out in the proximity of Tainan Taiwan Using the four ground reference stations surrounding Tainan the differential time of arrival positioning algorithm is employed to calculate the positions of aircraft passing above Tainan The positioning results show positive positioning result with positioning error around 100 meters horizontally However this experiment also showed the mechanism’s limitation on the positioning due to the geometry of stations In the second part of this thesis to overcome the geometry limitation a viable concept is developed based on a multi-measurement positioning algorithm A simulation is conducted to validate the proposed concept In comparison to the original WAM based APNT the results showed that the positioning service coverage is increased about 10% using multi-measurement positioning algorithm
Effect of ground station geometric distribution on wide area multilateration positioning performance
家昇, 郭. (Author). 2015 7月 30
學生論文: Master's Thesis