www.pudn.com > trackingdemos.zip > gene_2d_sen2.m

% gene_2d_sen2.m 
% 
% generate the measurements for a 2-D scenario of two closely spaced targets with  
% sensor 2 
function measurement = gene_2d_sen2(target) 
 
% define SNR 
SNRdb = 10; 
SNR = 10^(SNRdb/10); 
% detection threshold 
threshold = 2.55; 
% calc. the probability of detection and false alarm per cell  
% according to certain model (currently Swerling-I) 
Pfa = exp(-threshold*threshold/2); 
Pd = exp(-threshold*threshold/2/(1+SNR)); 
% measurement std, cell size 
C_r = 50; 
C_b = 2e-3; 
exp_FAs = 16*Pfa; 
sens1_pos = [0, 0]; 
sens2_pos = [1.8e5, .8e5]; 
numScan = length(target(1).time); 
 
for i=1:numScan 
    measurement(i).time = target(1).time(i); 
    measurement(i).flag = []; 
    measurement(i).range = []; 
    measurement(i).bearing = []; 
     
    x = sens2_pos(1); 
    y = sens2_pos(2); 
    measurement(i).pos = sens2_pos; 
    r1 = sqrt((target(1).state(1,i)-x)^2+(target(1).state(3,i)-y)^2); 
    r2 = sqrt((target(2).state(1,i)-x)^2+(target(2).state(3,i)-y)^2); 
    % This really depends on the target-sensor geometry 
    b1 = pi + atan((target(1).state(3,i)-y)/(target(1).state(1,i)-x)); 
    b2 = pi + atan((target(2).state(3,i)-y)/(target(2).state(1,i)-x));         
    delta_r = abs(r1-r2); 
    delta_b = abs(b1-b2); 
 
    ind = 1; 
    % a target detection 
    if rand < Pd 
        if delta_r>2*C_r | delta_b>2*C_b  % fully resolved 
            sigma_r = C_r/sqrt(12); 
            sigma_b = C_b/sqrt(12); 
            if rand < Pd  % fully resolved, two detections 
                measurement(i).flag(ind) = 1; 
                measurement(i).range(ind) = r1 + randn*sigma_r; 
                measurement(i).bearing(ind) = b1 + randn*sigma_b; 
                ind = ind + 1; 
                 
                measurement(i).flag(ind) = 1; 
                measurement(i).range(ind) = r2 + randn*sigma_r; 
                measurement(i).bearing(ind) = b2 + randn*sigma_b; 
                ind = ind + 1; 
                 
            elseif rand < .5 % fully resolved, one detection, target 1 
                measurement(i).flag(ind) = 1; 
                measurement(i).range(ind) = r1 + randn*sigma_r; 
                measurement(i).bearing(ind) = b1 + randn*sigma_b; 
                ind = ind + 1; 
                 
            else            % fully resolved, one detection, target 2 
                measurement(i).flag(ind) = 1; 
                measurement(i).range(ind) = r2 + randn*sigma_r; 
                measurement(i).bearing(ind) = b2 + randn*sigma_b; 
                ind = ind + 1; 
            end 
        elseif delta_r>C_r | delta_b>C_b   % partially unresolved 
            prob = (delta_r/C_r-1)*(delta_b/C_b-1); 
            if rand > prob 
                if rand < Pd 
                    measurement(i).flag(ind) = 0; 
                    sigma_r = C_r; 
                    sigma_b = C_b;             
                 
                    measurement(i).range(ind) = (r1+r2)/2 + randn*sigma_r; 
                    measurement(i).bearing(ind) = (b1+b2)/2 + randn*sigma_b; 
                    ind = ind + 1; 
                end 
            else 
                if rand < Pd 
                    measurement(i).flag(ind) = 1; 
                    sigma_r = (2-1/sqrt(12))*C_r - (1-1/sqrt(12))*delta_r; 
                    sigma_b = (2-1/sqrt(12))*C_b - (1-1/sqrt(12))*delta_b; 
 
                    measurement(i).range(ind) = r1 + randn*sigma_r; 
                    measurement(i).bearing(ind) = b1 + randn*sigma_b; 
                    ind = ind + 1; 
                end 
                if rand < Pd 
                    measurement(i).flag(ind) = 1; 
                    measurement(i).range(ind) = r2 + randn*sigma_r; 
                    measurement(i).bearing(ind) = b2 + randn*sigma_b; 
                    ind = ind + 1; 
                end 
            end 
        else          % fully unresolved, one detection 
            if rand < Pd 
                sigma_r = C_r; 
                sigma_b = C_b;             
                measurement(i).flag(ind) = 0; 
                measurement(i).range(ind) = (r1+r2)/2 + randn*sigma_r; 
                measurement(i).bearing(ind) = (b1+b2)/2 + randn*sigma_b; 
                ind = ind + 1; 
            end 
        end 
    end 
    numFAs = poissrnd(exp_FAs); % false alarms 
    for j=1:numFAs 
        measurement(i).flag(ind) = -1; 
        if rand>.5 
            measurement(i).range(ind) = r1 + C_r*60*(rand-.5); 
            measurement(i).bearing(ind) = b1 + C_b*60*(rand-.5); 
            ind = ind + 1; 
        else 
            measurement(i).range(ind) = r2 + C_r*60*(rand-.5); 
            measurement(i).bearing(ind) = b2 + C_b*60*(rand-.5); 
            ind = ind + 1; 
        end 
    end 
end