An improved stable algorithm of the reduction-to-the-pole at low latitudes
Zhang Qi1,2, Zhang Yingtang1, Li Zhining1, Fan Hongbo1
1. Department of Vehicle and Electrical Enginee-ring, Shijiazhuang Campus, Army Engineering University, Shijiazhuang, Hebei 050003, China; 2. Unit 94019 PLA, Hetian, Xinjiang 848000, China
Abstract：As the routine reduction-to-the pole (RTP) operator at low latitudes is usually unstable in the frequency domain,we propose an improved stable RTP algorithm at low latitudes.First the high frequency noise in amplification zones is suppressed with the local-suppression and global-suppression RTP approaches based on routine RTP operator (RO) modifications.Then the introduced parameters are optimized by calculating the correlation coefficient between the RTP results and the norma-lized source strength.RTP results with the optimal parameters are obtained,and the accuracy of these RTP results is accordingly improved.Finally,to resolve the problem of high-frequency amplification effect in the optimal RTP operators,the Tikhonov regularization method is utilized to stabilize the operators.Experimental results on theoretical model indicate that the proposed algorithm eliminates the high-frequency noise in the original data and improves the signal-to-noise ratio of the RTP results,and the accuracy and stability of the low latitude RTP are greatly improved.
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