Tracking based on the adaptation of double gains and feedforward initiation for burst DSSS signals

To promise code tracking precision of burst DSSS signals, an improved adaptive algorithm was proposed on the minimum mean-square error (MMSE) criterion to adjust double gains of code tracking loop. During each epoch, Gains of discriminator and NCO (numerical controlled oscillator) were all optimized, which avoid the problems of existing single gain adaptive algorithms, such as imprecision and instability. Meanwhile, focusing on the problem of carrier tracking, the feedforwad frequency estimation based on the first epoch was adopted to initiate FLL (frequency locked loop), which decrease the error of carrier tracking caused by the imprecision of the initial frequency value supplied by acquisition module. Compared with several existing algorithms, simulation results show the excellence of this algorithm.