An interference signal demodulation technique based on multistage orthogonal signal fusion algorithm

•The Multistage orthogonal signal fusion (MOSF) method incorporates multi-level orthogonal signal fusion.•Three-level frequency orthogonal carriers and three-order Bessel function make the demodulation results more accurate.•The MOSF method takes into account the effect of high-frequency harmonics and higher-order Bessel functions.•The phase demodulation results of the MOSF method exhibit higher signal-to-noise ratio (SINAD), lower total harmonic distortion (THD).•The MOSF method provides more accurate of signal, lower non-linear distortion, and lower phase delay error.