On the basis of the amplitude and frequency differences between echoes and radio-frequency interference(RFI),an improved empirical mode decomposition(EMD)algorithm was proposed.Firstly,the original signal including echo information and radio frequency interference was multiplied by agiven high frequency signal and which was moved to a high frequency band.Then,the EMD was used to decompose the echo information and radio frequency interference into different intrinsic mode functions(IMF),and the values higher...