Information Technology Journal1812-56381812-5646Asian Network for Scientific Information10.3923/itj.2011.440.445WangBiao YangGuang LiuGuoying 22011102A novel joint estimation algorithm is proposed for the multi-path number, the delay and the Doppler shift in the underwater acoustic channels. A single-frequency signal and a Chirp signal are sent with a fixed time interval T. And the fractional Fourier transform (FRFT) is applied to analyze the received signal. Two equations are listed according to FRFT and decorrelation and then the relation table of Doppler shift and delay is got. Besides, it’s not necessary to search for the order of received signal as the result of the invariant characteristic of the chirp rate, which greatly improves the algorithm efficient. The simulation results show the effectiveness of the algorithm.]]>Sharif, B.S., J. Neasham, O.R. Hinton and A.E. Adams,2000Calvo, E. and M. Stojanovic,2008Li, J., R. Jin and J. Geng,2006Stojanovic, M., J. Catipovic and J.G. Proakis,1993Pei, S.C. and W.L. Hsue,2006Tsimenidis, C.C., B.S. Sharif, O.R. Hinton and A.E. Adam,2005Yin, J., J. Hui and P. Cai,2007Yang, G., M. Li and L. Zhang,2009Zheng, Y.R., C. Xiao, T.C. Yang and W.B. Yang,2007Zheng, Y.R., C. Xiao, X. Liu, T.C. Yang and W.B. Yang,2008Zheng, Y.R., C. Xiao, T.C. Yang and W.B. Yang,2010