MATLAB: Filtering result in matlab

time difference of arrival

this is a set of possible solutions i get from my code.but i only need three values but i get 6 possible solutions.i know that my solution can neither be negative nor it can be complex and it should show only accepted answer after ignoring other solution

there are 6 possible solutions but only three are right. now how to use loop maybe to ignore left entries as it is negative and it should only display right entries as solution

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https://www.mathworks.com/matlabcentral/answers/601690-solution-of-3d-nonlinear-equation#comment_1031275

possibleSol(:, all(possibleSol>0 & imag(possibleSol)==0, 1))

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Change the last part of code like this

%%Filtering Results
idx = any(possibleSol < 0) | any(imag(possibleSol) ~=0);
possibleSol(:, idx) = [];
fprintf('Xs=%.f\nYs=%.f\nZs=%.f\n', possibleSol);
ax = axes();
hold on
grid on
view(3);
plot3(x,y,z, 'ro', 'LineWidth', 2, 'MarkerSize', 10)
plot3(possibleSol(1),possibleSol(2),possibleSol(3), 'b+', 'LineWidth', 2, 'MarkerSize', 10)

MATLAB: Solution of 3d nonlinear equation

x_p = 4; y_p = 5; z_p = 2;
x_1 = 8; y_1 = 9; z_1 = 5;
x_2 = 2; y_2 = 5; z_2 = 1;
x_3 = 6; y_3 = 1; z_3 = 3;
t1 = 5.692820*10^-9;
t2 = -2.924173*10^-9;
t3 = -12.010097*10^-9;
syms xs ys zs     %our unknowns
syms c            %constant not given in question 
eqn1 = sqrt((xs-x_p)^2+(ys-y_p)^2+(zs-z_p)^2)-sqrt((xs-x_1)^2+(ys-y_1)^2+(zs-z_2)^2)-(c*t1);
eqn2 = sqrt((xs-x_p)^2+(ys-y_p)^2+(zs-z_p)^2)-sqrt((xs-x_2)^2+(ys-y_2)^2+(zs-z_2)^2)-(c*t2);
eqn3 = sqrt((xs-x_p)^2+(ys-y_p)^2+(zs-z_p)^2)-sqrt((xs-x_3)^2+(ys-y_3)^2+(zs-z_3)^2)-(c*t3);
sol = solve([eqn1, eqn2, eqn3], [xs, ys, zs]);
disp(sol.xs)
disp(sol.ys)
disp(sol.zs)

the values will be parameterized in c, which you indicate is a known value, but which you did not provide a value for.

There are two solutions for each variable.

You should probably re-substitute the solutions and verify that the values work, as MATLAB warns that some of the solutions produced might no be true solutions.

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