基于EKF参数估计的光纤水听器PGC解调方法研究  

Phase Generated Carrier Demodulation Approach in Fiber-Optic Hydrophone Based on Extended Kalman Filter Parameter Estimation

作　　者：畅楠琪 黄晓砥[1] 王海斌[1] Chang Nanqi;Huang Xiaodi;Wang Haibin(State Key Laboratory of Acousties Institute of Acoustics Chinese Academ of Seiences,Bejing 100190,China;University of Chinese Academy of Seiences,Beijing 100049 China)

机构地区：[1]中国科学院声学研究所声场声信息国家重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《中国激光》2022年第17期103-114,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(62171440)。

摘　　要：针对光源调制引起的伴生调幅和相位偏移,直流光强、交流光强和调制深度的漂移以及载波相位延迟等因素对干涉型光纤水听器相位生成载波(PGC)解调结果的影响,本文提出了一种同时适用于PGC内调制和外调制的基于扩展卡尔曼滤波(EKF)参数估计的PGC解调方法(PGC-EKF方法)。结合考虑非线性因素影响的PGC解调模型,对传统的PGC解调过程进行改进,并引入基于EKF的椭圆拟合算法对该模型中的各未知参数进行估计;改进了现有任意椭圆一般方程的系数与其对应参数方程中参数的关系式的推导过程,修正了现有推导结果中错误的部分,简化了现有推导结果,并结合本文所用模型特点进行了进一步的推导。对PGC-EKF进行实验验证,结果表明,相比传统的PGC-Atan解调方法,本文提出的PGC-EKF方法将解调结果的信噪比提高了8.84dB,总谐波失真降低了19.25dB,信噪谐波比提高了17.16dB,系统性能有了明显提升。实验结果说明PGC-EKF方法能够比较有效地解调出待测信号,并抑制上述因素引起的波形失真和交流干扰。Objective High sensitivity,large dynamic range,and anti-electromagnetism interference are advantages of interferometric fiber-optic hydrophones.In the fields of marine resources exploration and seabed geological exploration,it has a good application potential.Phase generated carrier(PGC)modulation and demodulation technology have the advantages of high sensitivity,easy multiplexing,and good linearity.Interferometric optical fiber hydrophones commonly employ this signal detection technology.PGC demodulation approach includes internal and external modulation.PGC demodulation results can be affected by laser intensity modulation and laser phase excursion caused by directly modulating laser,fluctuations in direct-current laser intensity,alternating-current laser intensity,phase modulation depth,and phase delay due to laser transmission delay,circuit transmission delay,etc.Several viable approaches to eliminating these factors’influence have been researched by numerous previous studies.However,most of them only focus on some of the abovementioned nonlinear factors and one case of PGC internal or external modulation.We hope to propose an approach to eliminate the effects of the abovementioned nonlinear factors.Furthermore,we hope that this approach can be employed in both PGC internal and external modulations.Methods To eliminate these effects,a PGC demodulation approach based on extended Kalman filter parameter estimation(PGC-EKF)is proposed in this study.The traditional PGC demodulation process is modified in this study using the characteristics of the PGC demodulation model that considers the influence of nonlinear factors.In the modified PGC demodulation process,the PGC demodulation problem can be transformed into the estimation of four demodulation model parameters D,Ex/Ey,sin(θ_(x)-θ_(y))and cos(θ_(x)-θ_(y)).In this study,an ellipse fitting algorithm based on an extended Kalman particle filter is introduced to estimate the model’s parameters.An ellipse fitting algorithm can be employed to map the four dem

关 键 词：测量 干涉型光纤水听器 相位生成载波 扩展卡尔曼滤波 椭圆参数估计 

分 类 号：TH741[机械工程—光学工程]