it.m

迭代实现非线性函数（电离层延迟模型）的参数拟合问题

function delay=It(A1,B,alpha0,alpha1,alpha2,alpha3,beta0,beta1,beta2,beta3,gama0,gama1,gama2,gama3,t,fm)

A2=a2(alpha0,alpha1,alpha2,alpha3,fm);
A3=a3(gama0,gama1,gama2,gama3,fm);
A4=a4(beta0,beta1,beta2,beta3,fm);

x=2*pi*(t-A3)/A4;
    delay=(5+A1-B*fm)+A2*cos(2*pi*(t-A3)/A4);

if  (abs(x)>=1.57)
  delay= (5+A1-B*fm);
end