摘要在信息技术迅猛发展的今天，导航定位已成为军事和民用生活中不可或缺的技术。而由于通信距离遥远，卫星能供给的功率有限，电磁波到达接收机时幅度极其微弱，其本身极易受到干扰。加之军用中来自人为的干扰，更给导航定位的抗干扰性能带来极大的挑战。42779
本文首先介绍了抗干扰算法的原理，并用matlab建立四元阵列天线模型验证该算法的抗干扰效果。而后分别用FPGA与Microsoft Visual Studio C++两种方法来实现。根据指标要求，建立了FPGA实现抗干扰算法的平台，主要包括射频接收机、AD/DA数模转换、DDC数字上变频下变频模块、权值计算模块、信号加权求和模块。Microsoft Visual Studio C++直接对下变频后的中频信号进行处理，计算权值。最终将两种方法的计算结果与matlab所得进行比对，并对权值的更新时间和精度进行讨论。
关键词 北斗导航 LMS算法 空域功率倒置抗干扰 FPGA C++ 矩阵求逆
毕业论文设计说明书外文摘要
Title Design and Implementation of A Fast Anti-Jamming Algorithm for Beidou Navigation Systems based on FPGA
Abstract
Nowadays, with the rapid development of information technologies, the navigation satellite system has become an indispensable technology in military and daily life. In general, inter-users distances are vast, while the power of the transmitter is limited. So, when the electromagnetic wave arrives at receiver, the amplitude is extremely weak, easy to be disturbed. In addition, there may be artificial interference when used in military. It brings great challenge to the anti-jamming measures of the navigation and positioning.
In this paper, it first introduces the principle of anti-jamming algorithm, then build a four elements antenna array model in MATLAB, verifying the anti-jamming algorithm. It uses both FPGA and C++ to achieve the model separately. According to the requirement, it establishes a forum of FPGA, mainly including RF Receiver、analog-to-digital converters (ADCs) 、digital-to-analog converters (DACs)、digital up/down converter module、weight calculation and weighting signal calculation. Visual Studio C++ Microsoft directly uses IF signals, outputed by down-conversion mixer, calculating weights. Finally, the results of two methods are compared with that of MATLAB. Meanwhile, update time and accuracy are discussed separately.
Keywords Beidou navigation，C++，FPGA，LMS algorithm，Matrix Inversion，Space anti-jamming
目 次
1 绪论 1
1.1 课题背景 1
1.2 北斗导航抗干扰技术研究的必要性 2
1.3 北斗导航抗干扰技术研究的现状 3
1.4 本文的主要结构 3
2 空域功率倒置自适应抗干扰算法的理论推导 5
2.1 空域功率倒置自适应抗干扰算法的原理 5
2.2 空域功率倒置自适应抗干扰算法推导 5
3 抗干扰算法matlab仿真 8
3.1 频点干扰 8
3.2 宽带干扰 9
4 抗干扰算法的FPGA实现 10
4.1 选取采样率——带通采样定理 10
4.2 数字下变频/上变频DDC模块 13
4.3 浮点数运算 14
4.4 矩阵求逆 18
4.5 加权合成 FPGA北斗导航快速抗干扰算法设计与实现:http://www.751com.cn/tongxin/lunwen_43327.html