有一段程序，不是我编写的，用MATLAB仿真总是出现 下面这句话，我知道是矩阵下标不对了，可是怎么改呢，求指教

”Subscripted assignment dimension mismatch.

Error in Untitled3 (line 67)

miu(k,l) = cov(delta_r(k,i,j),delta_r(l,i,j))/(dd_r(k)*dd_r(l));“

代码如下：

L = 10; % 站间距

delta_tdoa = 1e-8; % 时差测量误差

delta_s = 0; % 站址测量误差

c = 3e5; % 光速(公里)

alpha = 30; % 站间夹角

d_r = delta_tdoa*c; % 距离差误差

% 计算站址

% s0

x0 = 0;

y0 = 0;

z0 = 0;

% s1

x1 = L*cos(30*pi/180);

y1 = L*sin(30*pi/180);

z1 = 0.1;

% s2

x2 = L*cos(150*pi/180);

y2 = L*sin(150*pi/180);

z2 = 0.2;

% s3

x3 = 0;

y3 = -L;

z3 = 0.3;

% he

xd = [x0,x1,x2,x3];

yd = [y0,y1,y2,y3];

zd = [z0,z1,z2,z3];

%

for i=1:401 % x km

for j=1:401 % y km

% 目标点

x(i,j) = (i-201);

y(i,j) = (j-201);

z(i,j) = 2;

% 目标到各站距离ri

for k = 1:4

r(k,i,j) = abs(sqrt((x(i,j)-xd(k))^2+(y(i,j)-yd(k))^2+(z(i,j)-zd(k))^2));

end

% 距离差Ari

for k = 2:4

delta_r(k-1,i,j) = r(k,i,j)-r(1,i,j);

end

% c

for k = 2:4

f(k-1,1) = ((x(i,j)-xd(1))/r(1,i,j))-((x(i,j)-xd(k))/r(k,i,j));

f(k-1,2) = ((y(i,j)-yd(1))/r(1,i,j))-((y(i,j)-yd(k))/r(k,i,j));

f(k-1,3) = ((z(i,j)-zd(1))/r(1,i,j))-((z(i,j)-zd(k))/r(k,i,j));

end

c = ((f'*f)^-1)*(f');

%miu

for m = 1:3

dd_r(m) = d_r; % ? 这里可以求统计平均

end

for k = 1:3

for l = 1:3

miu(k,l) = cov(delta_r(k,i,j),delta_r(l,i,j))/(dd_r(k)*dd_r(l));(就是这一句有错)

end

end

%e

for k = 1:3

for l =1:3

if k == l

e(k,l) = dd_r(k)^2 + 2*delta_s^2;

else

e(k,l) = miu(k,l)*dd_r(k)*dd_r(l) + delta_s^2;

end

end

end

% gdop

cc = 0;

for k = 1:3

for l = 1:3

cc = cc + (c(1,k)*c(1,l)+c(2,k)*c(2,l)+c(3,k)*c(3,l))*e(k,l);

end

end

gdop(i,j) = sqrt(cc);

end

end

%绘图程序：

figure;

mesh((-200:200),(-200:200),gdop(1:401,1:401).');

title('GDOP of axis');

xlabel('x axis *10e4(m)');

ylabel('y axis *10e4(m)');

figure;

contour((gdop(1:401,1:401)).',200);

title('contour line of GDOP');

xlabel('x axis *10e4(m)');

ylabel('y axis *10e4(m)');