GPSsignal_acq

实现基于软件无线电的OFDM系统仿真，利用USRP平台实现收发信号(The simulation of OFDM system based on software radio is realized, and the transceiver signal is realized by USRP platform.)

捷联惯导和GPS组合导航程序，包含初始对准和滤波算法(SINS and GPS navigation program, including the initial alignment and filtering algorithms)

说明：  下垂控制在逆变器型微电网控制中得到了广泛应用。当线路呈阻性时,有功功率和无功功率存在较强耦合,影响了下垂控制的性能。目前提出了两大类解决方法:一类方法通过控制参数的选取使逆变器的等效输出阻抗在基频段呈感性,但该方法的输出阻抗受制于控制参数并且存在较大缺陷;另一类方法用逆变器输出电流和虚拟阻抗计算电压降,从指令电压中减去该电压降,达到模拟实际阻抗的作用,效果更优,但对其机理缺乏阐述,且存在逆变器输出电压偏差问题。(Droop control is widely used in inverter based microgrid control. When the line is resistive, there is a strong coupling between active power and reactive power, which affects the performance of droop control. At present, two kinds of solutions are proposed: one is to make the equivalent output impedance of the inverter inductive in the fundamental frequency band by selecting the control parameters, but the output impedance of this method is subject to the control parameters and has great defects; the other is to calculate the voltage drop by using the output current and virtual impedance of the inverter and subtract the voltage drop from the command voltage to simulate the actual impedance, The effect is better, but its mechanism is lack of elaboration, and there is the problem of inverter output voltage deviation.)

说明：  matlab基础入门，适合新手学习matlab基础操作与功能(Introduction to matlab)

一种基于信号二阶四阶矩的信噪比估计方法，该文件中包含该方法的文章以及matlab程序。(This estimation method is based on the signal second-order signal-to-noise ratio of the fourth moment. The file contains a paper and a code.)

OFDM通信系统抗多径衰落干扰研究,顺便求OFDM系统中关于频谱偏移的估计与补偿的，(OFDM communication system of anti-multipath fading interference studies, the way for OFDM systems on the spectrum offset estimation and compensation,)

massive MIMO 系统的各种性能仿真(Performance simulation of massive MIMO system)

说明：  全套fastgps程序源码，附有注释，参考教材《GNSS应用与方法》(Full set of fastgps program source code, with notes, refer to the textbook "GNSS application and methods")

平移不变法用于消除图像变换产生的为吉布斯效应(Translation invariant method for the elimination of image transform generated effects for the Gibbs)

LDPC的矩阵生成，准循环码矩阵的生成，采用PEG算法生成，使用块矩阵方法(produce QC-LDPC matrix)