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Particle filter for robot localization using WiFi measurements

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20 Aug 2008 (Updated )

Tracking a robot with particle filter by correcting odometric measurements with WiFi signal

Demo illustring WiFi propagation loss in indoor building

Demo illustring WiFi propagation loss in indoor building

clear,close all
nb_pts                   = 100;
nr                       = 2;

option.TX                = 0;
option.RX                = 0;
option.path              = 0;



flp                      = load_flp('norwich01.flp');

temp                     = flp.geom.planes([1 , 4 , 7] , :);
xmin                     = min(temp(:));
xmax                     = max(temp(:));
temp                     = flp.geom.planes([2 , 5 , 8] , :);
ymin                     = min(temp(:));
ymax                     = max(temp(:));
temp                     = flp.geom.planes([3 , 6 , 9] , :);
zmin                     = min(temp(:));
zmax                     = max(temp(:));


vectx                    = (xmin:(xmax-xmin)/(nb_pts-1):xmax);
vecty                    = (ymin:(ymax-ymin)/(nb_pts-1):ymax);


[X , Y]                  = meshgrid(vectx , vecty);
Z                        = ((zmax-zmin)/2)*ones(nb_pts , nb_pts);
RX                       = [X(:) , Y(:) , Z(:)]';

figure(1)

plot_flp(flp , option);
title('select/add beacon'' positions by left click (right click for the last one)', 'fontsize' , 12)

hold on
[x , y]                 = getpts;
temp                    = (zmax-zmin)/2;
flp.info.TXpoint        = [x' ; y' ; temp(: , ones(1 , length(x)))];

% flp.info.TXpoint         = [6000 ; 6000 ; 500];


plot(flp.info.TXpoint(1 , :) , flp.info.TXpoint(2 , :) , 'c*');
drawnow
hold off


rs_amp                  = total_power3(flp.info.TXpoint , RX , flp.geom.planes , flp.geom.material , flp.info.fc , nr);


figure(2)
imagesc(vectx , vecty , 20*log10(reshape(sum(rs_amp , 1) , nb_pts, nb_pts)));
hold on
plot_flp(flp);
title(sprintf('top view (x - y), nr = %d',nr))
%title('three dimensional view')
xlabel('x in pixels')
ylabel('y in pixels')
zlabel('z in pixles')
axis xy
% view(0,90);
% axis equal
colorbar

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