A Fine-Acquisition Algorithm Based on Zoom-FFT and Quinn Interpolation for NSCC

Navigation signal based on compound carrier (NSCC), as a novel signal scheme for navigation augmentation, has flexible multi-carrier structure and various scheme parameters, which enable it to possess significant efficiency of navigation augmentation, and also provide auxiliary information for signal synchronism algorithm design. This paper, based on NSCC structure and its parameter configuration, proposed a fine acquisition algorithm combining Quinn interpolation estimator and Zoom-FFT analyzer for NSCC with wideband but sparse signal construction. The Quinn estimator improved rough frequency estimation form the full-length FFT analyzer and located sensitive frequencies for sub-carriers for Zoom-FFT analyzer. Then, the Zoom-FFT analyzer provided high frequency resolution with no obvious computation addition and achieved high-accuracy frequency estimations for fine acquisition by zooming pre-determined frequency range of interest and refining related spectrum. Both the theory analysis and simulation results illustrate that the proposed algorithm can greatly suppress the fence effect and enhance estimation accuracy for fine acquisition with low computation cost and implementation simplicity.