In this paper, a fast Fourier transform (FFT)-based symbol demodulation method is proposed for a satellite navigation augmentation signal orthogonally modulated using Cyclic-Hadamard code. The proposed method rearranges the code and performs zero-padding interpolation to enable discrete Fourier transform computation by using the radix-2 FFT algorithm. The proposed method was compared with a correlation receiver in terms of symbol demodulation performance and receiver implementation complexity. Simulation results revealed that the proposed method achieves the same symbol error rate as the correlation receiver while reducing the computational complexity required at higher data rates.