【作者】 张奕；

【导师】 曹运合； 李英军；

【作者基本信息】 西安电子科技大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 相控阵雷达利用波束形成技术,可以进行快速地波束扫描,形成低副瓣或波束赋形的天线方向图,使得其相比于传统雷达在抗干扰性能,目标跟踪的精度,多目标检测等方面都有了极大的提升。共形阵是相控阵雷达的一种发展形式,因其具有与载体表面共形的特点,能够有效地利用载体设施的表面积。共形阵不仅具有良好的空气动力学性能,还可节省载体空间,简化安装,因此共形阵天线在雷达、通信、导航等领域具有广泛的应用。本文以某型共形折面舰载火控雷达为原型,提出了基于折面阵的和差波束低副瓣方向图和自适应旁瓣对消的设计方案,并以该设计方案为基础,对该雷达的数字波束形成系统进行了硬件平台的设计及系统功能的软件实现。首先介绍了阵列波束形成的原理,再利用凸优化的方法对均匀折线阵和圆环阵的和差波束方向图进行了优化,使其和差波束方向图形成低副瓣并在某些方向上具有零陷,且使得优化后的角误差曲线与原始的角误差曲线保持一致,减小对阵列测角性能的影响。接着推导了共形折面阵的波束形成公式,在此基础上,再利用两级加权的思想对其和差波束方向图提出了一种低副瓣的优化方法,并进行了MATLAB仿真分析。然后根据雷达自适应旁瓣对消的原理,设计了基于一种折面相控阵雷达的自适应旁瓣对消方法,并仿真了其对消性能。其次根据提出的折面相控阵雷达的和差波束低副瓣算法及自适应旁瓣对消方法,设计了某型舰载火控雷达的数字波束形成系统。首先通过对该系统数据实时处理能力以及数据通信能力的分析,确定了该系统的硬件平台以FPGA和DSP为核心架构,再通过对电源、时钟、通信接口等主要外围电路的设计,最终设计出了该系统所要求的硬件平台。在该硬件平台之上,按照该系统的设计要求对其进行功能模块的划分,包括了数据通信模块、波束形成模块、校准模块等,并对各功能模块的任务及实现方法进行了分析,完成了相应的程序编写及调试。接着各功能模块的程序进行了在线仿真及功能测试,验证了程序设计可行性的正确性。最后对在系统联调时遇到的光纤数据传输的误码和丢数问题以及链路口通信的误码问题进行了分析并提出了相应的解决方法。对光纤数据传输时遇到的误码和丢数问题,提出了在发送端使用预加重,在接收端进行信道均衡,扩展弹性缓冲器等解决方法;对链路口通信时遇到的误码问题,提出了添加链路口约束,设置帧复位信号的解决方法,降低了数据传输的误码率,提升了系统的稳定性。更多还原

【Abstract】 With application of Beam Forming technology,phased array radar can scan beams fast and easily realize the low side-lobe and beam-shaped antenna patterns.Compared with conventional radar,phased array radar has been greatly improved in the performance of multi-object detection and tracking precision and capability of anti-interfere.At the present time,conformal array radar has already become the main development direction of phased array radar.Due to the characteristic of conforming to a prescribed shape,conformal array radar can utilize the surface area of the carriers effectively.Conformal array radar not only has a good aerodynamic performance,but also can save the carrier space and simplify the installation.So the conformal array radar is widely applied in the fields of reconnaissance,communication and navigation etc.This paper proposes design methods about realizing the low side-lobe of the sum and difference beam and the adaptive side-lobes cancellation,which is based on a ship-borne bended surface conformal phased array radar.Then project development and implementation of digital beam forming algorithm are carried out on this radar by expounding the design methods.Firstly,this paper introduces the basic principle of digital beam forming,and the sum and difference beams of uniform polygonal linear array and circular array are optimized by using the convex optimization,so that the arrays can generate the low side-lobe of the sum and difference beam patterns and weak the interference in the required direction,at the same time,the optimized angle error curve is consistent with the original angle error curve,which has no affection with the angle measuring performance.Then deduces the beam forming formula of a bended plane array,and proposes a method about forming low side-lobe sum and differential beam patterns based on the form of a two-stage weighted theory.Next,the corresponding simulation system model is established and the simulated program is validated by MATLAB simulation.According to the principle of adaptive sidelobes cancellation,a scheme of adaptive sidelobes cancellation is proposed based on a bended plane array and the performance of cancellation is analyzed with simulation.Secondly,according to the methods about realizing the low side-lobe of the sum and difference beam and the adaptive sidelobes cancellation,this paper designs and implements the digital beam forming system of a ship-borne bended surface conformal phased array radar.Through the analysis of the ability of data throughput and signal processing capabilities,a FPGA and DSP-based hardware processing platform was determined.With the part of peripheral circuit in the design,such as the power,clock,communication interface,etc.,we got the hardware platform meeting the requirements of the digital beam forming system.On this hardware platform,in accord with the design requirements we divide the function modules of the system,includes the data communication module,the beam forming module the calibration module and so on.The tasks and implementation of each functional module is analyzed and the compiling and debugging of the corresponding program is completed.Then each functional module of the system was simulated by software and tested online by using some test data,in order to verify the feasibility and correctness of the system design.Finally,this paper analyzes the problems of bit errors and lost packets when data is transmitted by fiber and link ports during the system intermodulation and proposes some corresponding solutions.For the problems of bit errors and lost packets when data is transmitted by fiber,this paper proposes some solutions,includes,using pre-weighted technology at the transmitter,increasing the equalizer in the receiver to compensate channel properties,extending the elastic buffer.For the problems of bit errors when data is transmitted by link ports,this paper proposes some solutions,includes,carrying on the timing and location constraints,setting the Frame Reset feature,which can reduce the rate of error codes from the data transmission and enhance the stability of the system.更多还原