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For satellite navigation and positioning receiver is easy to be interferenced by the multipath, this paper presented an accurate tracking method which was based on maximum likelihood estimation and Kalman filtering for multipath BOC (n,n) signal. Firstly, the method made coherent integral accumulation for the receiving signal, and then estimated amplitude and delay of the signal by the method of maximum likelihood, next estimated the estimated result again by Kalman filtering, so got the more accurate multipath amplitude and delay under the low carrier-to-noise ratio. Finally, it used multipath estimation delay lock loop to analyze the phase curves and showed its validity by a simulation experiment. Theory and simulation results show that the method can track multipath BOC (n,n) signal accurately under the low carrier-to-noise ratio. [ABSTRACT FROM AUTHOR]

In order to solve the problem of the OFDM broadband signal processing, this paper introduced a algorithm for the direction of arrival (DOA) estimation of OFDM signal based on the wideband signal covariance matrix sparse representation. It averaged the triangle elements in the lower left corner of the main diagonal of the covariance matrix to form a new vector, and wrote the vector in the form of a redundant dictionary. The signal in a redundant dictionary the sparsity constraints formed a second-order cone constrained optimization problems, and then used toolbox SeDuMi to do DOA estimation. Theoretical analysis and simulation results show that the proposed method is an effective wideband signal DOA estimation algorithm and has high resolution in low signal-to-noise ratio and less number of snapshots, it is better than higher order cumulant algorithm and wideband focused matrix algorithm DOA estimation method. [ABSTRACT FROM AUTHOR]

In order to reduce the complexity of ACELP ( algebraic code excited linear prediction), and achieve a better operation in real-time system, this paper proposed an effective algorithm. First, it proposed the discontinuous open-loop pitch estimation in adaptive codebook search, used the time decimation factor in different delays, and then proposed the unified pulse-replacement search algorithm in stochastic codebook search, used the prediction technique and judging mechanism to control the number of codebook search. Finally, it simulated the improved algorithm in G. 729A. The result shows that the proposed algorithm not only acquires complexity reduction but also get a high speech quality. [ABSTRACT FROM AUTHOR]