%攻擊垂直機動目標比例導引三維彈道仿真
clear;
tt=0.001;
sm=500*tt;    %導彈
v=100;          %目標
st=v*tt;
x(1)=0;y(1)=0;z(1)=0;
pmr(:,1)=[x(1);y(1);z(1)];
ae=pi/180;r0=500;h0=100;b0=20*ae;e0=asin(h0/r0);
x0=r0*cos(e0)*sin(b0);y0=r0*cos(e0)*cos(b0);z0=h0;dt=0.001;
ac=-100;
ptr(:,1)=[x0;y0;z0];
m=1;
q(1)=0;
o(1)=0;
a(1)=0;
for(k=2:5000)
    if(k>=500)              %設置目標機動
        ac=200;
    end
    zu=v^2/ac;
    de=ac*dt/v;
    em=e0+de;
    xm=x0+2*zu*sin(de/2)*cos(de/2+e0)*cos(b0);
    ym=y0+2*zu*sin(de/2)*sin(de/2+e0)*sin(b0);
    zm=z0+2*zu*sin(de/2)*sin(de/2+e0);
    e0=em;
    x0=xm;
    y0=ym;
    z0=zm;
    ptr(:,k)=[xm;ym;zm];
    r(k-1)=sqrt((ptr(1,k-1)-pmr(1,k-1))^2+(ptr(2,k-1)-pmr(2,k-1))^2+(ptr(3,k-1)-pmr(3,k-1))^2);
    c=sqrt((ptr(1,k)-pmr(1,k-1))^2+(ptr(2,k)-pmr(2,k-1))^2+(ptr(3,k)-pmr(3,k-1))^2);
    b=acos((r(k-1)^2+st^2-c^2)/(2*r(k-1)*st));

    dq=acos((r(k-1)^2-st^2+c^2)/(2*r(k-1)*c));
    if abs(imag(b))>0
        b=0.0000001;
    end
    if abs(imag(dq))>0
        dq=0.0000001;
    end
    q(k)=q(k-1)+dq;
    o(k)=o(k-1)+m*(dq);
    a(k)=o(k)-q(k-1);

    c1=r(k-1)*sin(b)/sin(a(k)+b);
    c2=r(k-1)*sin(a(k))/sin(a(k)+b);
    c3=sqrt((c1-sm)^2+(c2-st)^2+2*(c1-sm)*(c2-st)*cos(a(k)+b));
    dq=a(k)-acos(((c1-sm)^2+c3^2-(c2-st)^2)/(2*(c1-sm)*c3));
    if abs(imag(dq))>0
        dq=0.0000001;
    end
    q(k)=q(k-1)+dq;
    o(k)=o(k-1)+m*(dq);
    a(k)=o(k)-q(k-1);
    c1=r(k-1)*sin(b)/sin(a(k)+b);
    c2=r(k-1)*sin(a(k))/sin(a(k)+b);
    c3=sqrt((c1-sm)^2+(c2-st)^2+2*(c1-sm)*(c2-st)*cos(a(k)+b));
    x1(k)=ptr(1,k-1)+c2/st*(ptr(1,k)-ptr(1,k-1));
    y1(k)=ptr(2,k-1)+c2/st*(ptr(2,k)-ptr(2,k-1));
    z1(k)=ptr(3,k-1)+c2/st*(ptr(3,k)-ptr(3,k-1));
    x(k)=pmr(1,k-1)+sm/c1*(x1(k)-pmr(1,k-1));
    y(k)=pmr(2,k-1)+sm/c1*(y1(k)-pmr(2,k-1));
    z(k)=pmr(3,k-1)+sm/c1*(z1(k)-pmr(3,k-1));
    pmr(:,k)=[x(k);y(k);z(k)];
    r(k)=sqrt((ptr(1,k)-pmr(1,k))^2+(ptr(2,k)-pmr(2,k))^2+(ptr(3,k)-pmr(3,k))^2);
    if r(k)<2;break;end;
end;
sprintf('遭遇時間:%3.1f',0.001*k),
figure(1);
plot3(pmr(1,:),pmr(2,:),pmr(3,:),'k',ptr(1,:),ptr(2,:),ptr(3,:));
%text(x(80),y(80),z(80),'\leftarrow 比例導引');
%axis([0 100 0 100 0 100]);
grid on