Developing an improved adaptive algorithm to eliminate the mono tone jammer effect on the pulse radar

In order to demolition of performance in radar systems, intentional jamming is used. One of the best methods to delete the effect of jammer is to use the adaptive filters. Adaptive filters are categorized to linear or nonlinear. The disadvantages of nonlinear adaptive filters are computational complexity and implementation. In the radar systems, it is commonly used the linear adaptive algorithms to prevent the saturation of receiver. Linear algorithms don't have any feedback and are resistant against saturation. In this paper, a linear adaptive algorithm based on NLMS algorithm is introduced which is named as improved NLMS algorithm. Improved NLMS algorithm is simulated for input signal of pulse radar affected by jamming and is compared with existing algorithms in terms of efficiency. Output SJR versus input SJR for each algorithm is plotted. Simulation results show that, for input SJR equal to 5 dB, the output SJR improves approximately equal to 6db for RLS algorithm and 8db for NLMS algorithm, respectively. For such input SJR, the proposed algorithm shows 11 dB improvement in output SJR versus to input SJR. This means that the proposed algorithm creates 3dB improvement compared to the best existing adaptive filter. This improvement is obtained by increasing the computational complexity compared to the NLMS algorithm.