航道多载波的通信时延与多普勒频移联合估计

航道多载波的通信时延与多普勒频移联合估计
陈宗恒
(上海海事局厦门航标处，福建厦门361012)
［摘要］针对海上航道立体监测系统中水声信道高斯噪声和对称α稳定(SαS,Symmetric α Stable)脉冲噪声干扰的复杂环境，以基带OFDM（Orthogonal Frequency Division Multiplering）水声通信系统的发射信号作为研究对象，提出了一种基于分数低阶循环模糊函数的多循环频率时延与多普勒频移联合估计算法．该方法将分数低阶矩与循环平稳特性相结合，能够在SαS脉冲噪声条件下检测信号的循环平稳特性．仿真结果表明：在脉冲噪声和干扰环境中该算法均能稳定工作，估计性能优于基于二阶循环模糊函数．
[关键词]航道立体监测；OFDM；对称α稳定分布噪声；模糊函数；时间延迟；多普勒频移
The Joint Estimation of the Time Delay and Doppler Shift in the
Multi-Carrier Waterway
CHEN Zong-heng
(Shanghai Maritime Safety Administration，Xiamen Navigation Aid Department，
Xiamen 361012,China)
Abstract：In Response to the complex environment of the acoustic channel gauss noise and SαS impulse noise in the maritime waterway dimensional monitoring system，and with the transmitted signal of the baseband OFDM in the acoustic communication system as the research object，this paper proposes a joint time delay and Doppler frequency shift estimation algorithm based on the fractional lower order cyclic ambiguity function with multi-cycle frequency time delays.This method，which combines the fractional lower order moment with the feature of cycle stationary，can detect the signal characteristic of cyclo stationarity under the SαS impulse noise. The algorithm takes full advantage of the cyclic frequency information of the signal，and is capable of suppressing interference. The simulation results show that the algorithm proposed in this paper can work very well in the presence of
the impulse noise and interference，is superior to the algorithm based on the second order cycle fuzzy function，and is a robust joint estimation algorithm of time delay and Doppler frequency shift.The application of the algorithm will greatly improve the
reliability and stability of the communication between the buoys and underwater static and motive monitoring devices.
Key words：waterway dimensional monitoring;OFDM;SαS noise;ambiguity function; time delay;Doppler shift。