Abstract:

When the transmitting waveform is steppedfrequency chirp signal with randomly sparse frequency and aperture, it can not only reduce the requirement of the sampling rate, but also improve the antijamming ability. However, the disadvantage is that it is difficult to make the motion compensation. A motion compensation method based on global minimum entropy is proposed. Firstly, we use the global minimum entropy method to complete the envelope alignment. Secondly, we convert the problem of initial phase correction into the problem of parameter estimation of radial velocity and acceleration. In order to obtain high estimation precision of the velocity, we combine the rough searching and precise estimation together, taking the global minimum entropy as the cost function, and search with variable step lengths based on the goldensection method, then, the parameter estimation method becomes fast and highly precise. Theoretical analysis and simulation results show that the proposed algorithm has the advantages of fast calculation speed, high estimation accuracy and high robustness under low SNR conditions.