超视距雷达信号处理与参数估计研究

发布时间：2018-09-19 15:50

【摘要】：高频天地波超视距雷达采用电离层反射和地波绕射相结合的传播模式,由于这种特殊的组合信道,使得该种雷达工作时易受到电离层、地波传播损耗、海杂波、海态及环境噪声的影响。本文着眼于天地波超视距雷达信号处理中常见的问题,主要分析了天地波模式下一阶海杂波的展宽特性及其统计特性,然后对海杂波的抑制及目标的参数估计问题进行了研究,本文的主要内容如下:(1)海杂波的建模与特性研究针对一阶海杂波的展宽问题,首先建模和分析了一阶海杂波的空间分布特性,从理论上证明了在固定距离门的情况下,海杂波的空间分布可以用一椭圆方程来描述;然后结合前人的研究,给出了Bragg散射频率的计算公式;最后根据海杂波散射截面积的计算式,仿真了不同因素对其的影响。仿真结果表明,海杂波散射截面积与雷达工作频率、双基地角、风向和风速都有密切关系。(2)海杂波抑制算法的研究针对海杂波的抑制问题,首先对传统循环对消方法进行了仿真验证,说明了传统方法中存在的问题,进而对传统方法进行改进,增强了算法的实用性;最后针对前两种算法存在的缺陷,进一步给出了基于高精度频率估计的海杂波抑制算法,仿真结果表明,该方法能更精确地估计复正弦信号的参数,更高效地抑制海杂波。(3)目标参数估计的研究针对目标参数估计的问题,将运动目标在空间中的位置用高阶多项式来表示,随后基于该模型给出一种最大似然估计式,用于估计目标的初始位置、速度和加速度。通过推导对应参数的CRB,结合仿真结果,检验了该估计式的估计性能。
[Abstract]:The high frequency surface-wave over-the-horizon radar uses the propagation mode of ionospheric reflection and ground wave diffraction. Because of this special combined channel, the radar is vulnerable to ionosphere, ground wave propagation loss and sea clutter. Effects of sea and environmental noise. This paper focuses on the common problems in the signal processing of OTH radar, mainly analyzes the broadening characteristics and statistical characteristics of the first order sea clutter under the ground and earth wave mode, and then studies the suppression of the sea clutter and the parameter estimation of the target. The main contents of this paper are as follows: (1) the modeling and characteristics of sea clutter; aiming at the broadening problem of first order sea clutter, the spatial distribution characteristics of first order sea clutter are first modeled and analyzed, and it is proved theoretically that in the case of fixed distance gate, The spatial distribution of sea clutter can be described by an elliptic equation, and then the formula of Bragg scattering frequency is given based on previous studies. Finally, according to the formula of sea clutter cross section area, the influence of different factors on sea clutter scattering frequency is simulated. The simulation results show that the cross section area of sea clutter is closely related to the radar operating frequency, bistatic angle, wind direction and wind speed. (2) the research of sea clutter suppression algorithm is aimed at the suppression of sea clutter. First of all, the traditional circular cancellation method is verified by simulation, which explains the existing problems in the traditional method, and then improves the traditional method to enhance the practicability of the algorithm. Finally, aiming at the defects of the first two algorithms, Furthermore, a sea clutter suppression algorithm based on high precision frequency estimation is presented. The simulation results show that the proposed method can estimate the parameters of complex sinusoidal signals more accurately. (3) aiming at the problem of target parameter estimation, the position of moving target in space is represented by high-order polynomial, and then a maximum likelihood estimation formula is given based on the model. Used to estimate the initial position, velocity, and acceleration of a target. The estimation performance of the estimator is tested by deducing the corresponding parameters of CRB, combined with the simulation results.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN957.51

【相似文献】