jam_eff.m

此程序给出了不同情况的雷达距离测量仿真平台

% jam_eff
%
% Calculates the effect of jamming.  Takes inputs from both
% the self-screening and stand-off jamming processes
%
%

% if SSJ, account for that with aax factor
%
if SSJ==1
	aax = (range_index./rng_ssj_only).^4;
else
	aax = 0;
end;

% If stand-off jamming as well, figure in those effects
% or, if SOJ only, then account for that
%

if SOJ==0
	bbx = 0;
else
	bbx = (range_index./rs00).^4;
end

rc = ranges_clear .* 1.854;
rss = (rng_ssj_only .* (10.^((-det_facts)./40))) .* 1.854;

rxx = rss;

rxdel = 0;
done = 0;
while done==0
	rxx = rxx - rxdel;
	lax = sx .* re *(1-exp(-rxx ./ re));
	lwx = wx .* rxx;
	lxx = 10.^((lax+lwx)./20);
	lyy = 10.^((lax+lwx)./10);
	xfrx = .4343 .* log(rxx ./ rc) + .4343 * (log(lyy + aax * lxx + bbx)) ./ 4;
	dlxx = 2.3026 .* lxx .* ((1 ./ rxx) + wx / 20 + (sx / 20) .* exp(-rxx ./ re));
	dlyy = 2.3026 .* lyy .* ((1 ./ rxx) + wx / 10 + (sx / 10) .* exp(-rxx ./ re));
 	dfrx = (1./ rxx) + (dlyy + aax * dlxx) ./ (4 * (lyy + lxx * aax + bbx));
     	rxdel = xfrx./dfrx;
        a = find(abs(rxdel) <= 0.1);
	b = length(a);
	if b > 0
		for i = 1:b,
			rxdel(a(i)) = 0;
		end
	end
	if rxdel <= 0.1
		done = 1;
	end
end


% Print out ranges after jamming accounted for
%
after_jam_ans = [lax; lwx; (rxx./1.854)];

fprintf('Detection Range with Jamming\n\n');
fprintf('Swerling Case                         0          1       '); ...
fprintf('    2          3           4         1FA      3FA\n');
fprintf('Atmospheric Atten (dB)      ');fprintf('%-10.2f',lax);fprintf('\n');
fprintf('Weather Atten (dB)             ');fprintf('%-10.2f',lwx);fprintf('\n');
if max(rxx<50);
fprintf('Jamming Range  (n mi)       ');fprintf('%-10.2f',rxx/1.854);fprintf('\n');
else,
   fprintf('Jamming Range  (n mi)       ');fprintf('%-9.2f',rxx/1.854);fprintf('\n');
end;   

rxx = (rxx / 1.854);
lea = lax;
ler = lwx;

% Set Figure Parameters

ra=rx/1.854;
yz=[ra' rxx'];
z=0:6;
rmx=1.2*max(ra);

figure
bar(z,yz);
if rmx<50;set(gca,'YTick',[0:5:rmx]);
else,set(gca,'YTick',[0:10:rmx]);end;
if rmx<10;set(gca,'YTick',[0:1:rmx]);end;
set(gca,'XTicklabel','0|1|2|3|4|1FA|3FA');
xlabel('Swerling Case ')
ylabel('Range in NMI')
% axis([-1 7 0 rmx]);
title('Detection Range','Fontsize',12,'Fontweight','bold');
for ii=1:7;
   if ii==1;
      text(ii-.9,1.05*rxx(ii),'jam');
      %text(ii-1.5,1.03*ra(ii),'w/o jam');
   else
      text(ii-.9,1.05*rxx(ii),'jam');
      %text(ii-1.5,1.03*ra(ii),'w/o jam');
   end;
 end;