An AltBOC union tracking method based on ionospheric delay estimation

The code phase of the two side lobes of Galileo E5 alternative binary offset carrier (AltBOC) is dispersed by the ionosphere. Therefore, an ionospheric delay estimation based AltBOC union tracking method is proposed. In this method, the ionospheric delay of two side lobes is estimated based on the dual frequency measuring results which are utilized to adjust the channel delay of two side lobes, so as to synchronize the code phases of the two side lobes. By coupling the pseudorandom code of the two side lobes, the union tracking of the dual lobes AltBOC signal is realized. The theoretical analysis indicates that the method is able to effectively compensate the dispersion of the dual bands brought by the ionosphere for the AltBOC signal. The simulation result showed that the proposed method makes full use of the AltBOC sharp autocorrelation function and the performance of the multipath mitigation is improved, especially when the signal to noise ratio is high.