How to create a fixed user who receives GNSS signals within a map made from 3D plot?

https://kr.mathworks.com/help/nav/ug/simulate-gnss-multipath-effects-on-uav-flying-in-urban-environment.html

I would like to refer to the example of matlab above to create a user who is statically fixed in the middle of the map, not a user who moves along the trajectory.

So I modified it a little bit and wrote the code, and when I run it, the figure comes out well, but there's an unknown error, so I need some help.

Error using fusion.internal.GPSSensorBase/validateInputsImpl (line 302)

Expected input to be an array with number of columns equal to 3.

Error in deepseek_v01 (line 31)

[lla, velocity] = gps(position, zeros(1,3));

^^^^^^^^^^^^^^^^^^^^^^^^^

I'm getting this error, and I'm curious about the solution. I'm also curious if there's any problem even if I ignore the error and use it.

The .osm file I use is not attached, so you can use the .osm file that Matlab supports by default.

referenceLocation = [37.498759 127.027487 0];
scene = uavScenario('ReferenceLocation', referenceLocation, 'UpdateRate', 10, 'StopTime', Inf);

buildingColor = [0.8 0.8 0.8];
if isfile('gangnam_11exit.osm')
    addMesh(scene, 'buildings', {'gangnam_11exit.osm', [-250 250], [-250 250], 'auto'}, buildingColor);
else
    addMesh(scene, 'buildings', {'random', [-150 150], [-150 150], [10 50]}, buildingColor);
end

user = uavPlatform('User', scene, 'ReferenceFrame', 'ENU', 'InitialPosition', [0 0 80]);

gps = gpsSensor('UpdateRate', 10, ...               
               'ReferenceLocation', referenceLocation, ...
               'HorizontalPositionAccuracy', 1.6, ... 
               'VerticalPositionAccuracy', 3.0, ...   
               'VelocityAccuracy', 0.1);             

fig = figure('Name','Static GNSS User');
ax = show3D(scene);
hold(ax, 'on');
axis(ax, 'equal');
grid(ax, 'on');
view(ax, 3);
plot3(ax, 0, 0, 80, 'ro', 'MarkerSize', 12, 'MarkerFaceColor', 'r');

setup(scene);
while ishandle(fig)
    [position, orientation] = user.read();

    [lla, velocity] = gps(position, zeros(1,3)); 

    fprintf('[ENU Position] X: %.2fm, Y: %.2fm, Z: %.2fm\n', position(1), position(2), position(3));
    fprintf('[GPS Coordinates] Lat: %.6f°, Lon: %.6f°, Alt: %.2fm\n\n', lla(1), lla(2), lla(3));

    show3D(scene, 'Parent', ax, 'FastUpdate', true);
    drawnow limitrate;
    
    advance(scene);
end

Answer 1

[Ryan Salvo]

The output of the read object function of uavPlatform is not position, but a 16-element motion vector. The gpsSensor object expects a 3-element position vector. This can be obtained by indexing into the motion vector.

[motion, orientation] = user.read();
position = motion(1:3);

[lla, velocity] = gps(position, zeros(1,3));

[inhyeok]

Thank you. I'd like to ask you an additional question, but it doesn't make an error, but the result value keeps printing out, do you know a solution to this as well?

[Ryan Salvo]

The fprintf command within the for-loop is most likely causing the result to repeatedly print.