【作者】 张艳丽；

【导师】 邱天爽；

【作者基本信息】 大连理工大学 ， 信号与信息处理， 2006， 硕士

【摘要】 本文研究了在雷达、声纳、通信等领域中有着广泛和重要应用的时间延迟估计问题。文中针对不同的应用条件，包括不同的噪声及干扰特性，辐射源、接收传感器、以及反射目标之间的相对运动情况等等，建立了不同形式的信号模型，并对这些模型进行了比较深入的分析。文中给出了三种具有理论及实用价值的算法，并通过计算机仿真实验验证了所提算法的有效性。 通过大量文献阅读，本文对基于二阶、分数低阶、循环平稳统计特征的时延估计以及时延和多普勒频移联合估计方法进行了概括和总结，分析了各种方法的适用性和必要性。 本文的工作重点及创新包括以下几个方面： (1)分析了辐射源、接收传感器、以及反射目标之间无相对运动的情况。由于α稳定分布噪声的存在会降低基于二阶及以上统计量的传统方法的性能，本文将分数p阶相关与循环相关函数结合，给出了一种在脉冲噪声条件下具有信号选择性的时延估计方法。仿真实验表明它优于传统二阶循环统计量算法，并且与共变等基于分数低阶统计量的时延估计方法相比具有信号选择性。 (2)在特定情况下，辐射源、接收传感器、以及反射目标之间的相对运动可以等效为一个固定时延和一个多普勒频移。为了有效的联合估计在脉冲噪声存在时的时延和多普勒频移，给出了一种基于p阶循环模糊函数的方法。该方法比基于二阶、分数低阶和循环模糊函数的方法具有更好的准确性。 (3)提出了一种适应于α稳定分布噪声存在条件下，具有信号选择性的自适应时延估计方法。该方法提出的基础是将分数低阶统计特征与循环相关函数相结合。计算机仿真实验表明，所提出的方法可有效估计高斯噪声和脉冲噪声条件下的时变和非时变时延值，其性能不仅优于基于二阶循环相关的自适应时延估计算法，而且优于最小平均p范数(Least Mean p-norm，LMP)自适应时延估计方法。更多还原

【Abstract】 This thesis focuses on the time delay estimation problem which has various and important applications in the fields of radar, sonar, communications and so on. Corresponding to different application conditions, such as noise/interference properties, relative motions between transmitters, receivers and reflectors, different models are developed and analyzed in detail. Three theoretically and practically valued algorithms are proposed. Computer simulations are given to verify the efficiency of these proposed algorithms.Approaches using second order, fractional lower order and cyclonstationary statistics to estimate time delay (with/without Doppler shift) are summarized. Their applicabilities, and indispensabilities between each other are carefully analyzed.The main work and innovation of this thesis can be concluded as follows:(1) The situation which is no relative motions between transmitters, receivers and reflectors is considered. In the presence of additive impulsive noise, the methods which based on second and higher order statistics are degraded. In this thesis, combination of p th order correlation and cyclic correlation is considered. Furthermore, an approach for estimating time delay with signal selectivity in the presence of impulsive noise is developed. Simulations show that the performance of proposed algorithm is not only better than second order cyclic correlation, but also the covariation.(2) In certain circumstance, relative motions can be discibed as a fixed time delay and Doppler shift. For jointly estimating time delays and Doppler shifts in the presence of impulse noise, a new algorithm is proposed, which utilizes the p th order cyclic ambiguity function. The proposed algotithm has better estimation accuracy than second order, fractional lower order and cyclic ambiguity function.(3) A new adaptive time delay estimation method is proposed for highly corruptive environments considered the cyclostationary property of the source signal, which is based on the combination of the fractional lower order statistics and cyclic correlation. Simulations show that the performance of the proposed algorithm is superior to the LMP (Least Mean p -norm) time delay estimation method and adaptive time delay estimation method based on second order cyclic correlation in alpha-stable distributed noises.更多还原