What happened to my solver script?

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imcuser1 2017-6-14

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评论： imcuser1 2017-6-14

I am studying the calculation of GPS coordinates. I am expecting matlab giving me the origin and zero clock offset. However Matlab hangs and unable to solve.

syms x y z t
sv1 = [1 0 0];
sv2 = [0 1 0];
sv3 = [0 0 1];
sv4 = [1 1 1];
prange = [1 1 1 sqrt(3)];

pos = solve( ...
'((x-sv1(1))^2 + (y-sv1(2))^2 + (z-sv1(3))^2)^0.5 + t = prange(1)', ...
'((x-sv2(1))^2 + (y-sv2(2))^2 + (z-sv2(3))^2)^0.5 + t = prange(2)', ...
'((x-sv3(1))^2 + (y-sv3(2))^2 + (z-sv3(3))^2)^0.5 + t = prange(3)', ...
'((x-sv4(1))^2 + (y-sv4(2))^2 + (z-sv4(3))^2)^0.5 + t = prange(4)', x, y, z, t);

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Answer 1

Steven Lord 2017-6-14

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Don't pass char vectors into solve. If you're using release R2012a or later, use == to create your equations. We started warning about passing char vectors into solve in release R2015a, according to the Release Notes.

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imcuser1 2017-6-14

在 MATLAB Online 中打开

Thank you. Yes I use 2013a. Managed to make it work.

clear all; clc;
syms x y z t
sv1 = [1 0 0];
sv2 = [0 1 0];
sv3 = [0 0 1];
sv4 = [1 1 1];
prange = [1.1 1.1 1.1 sqrt(3.63)];
[a, b, c, d] = solve( ...
((x-sv1(1))^2 + (y-sv1(2))^2 + (z-sv1(3))^2)^0.5 + t == prange(1), ...
((x-sv2(1))^2 + (y-sv2(2))^2 + (z-sv2(3))^2)^0.5 + t == prange(2), ...
((x-sv3(1))^2 + (y-sv3(2))^2 + (z-sv3(3))^2)^0.5 + t == prange(3), ...
((x-sv4(1))^2 + (y-sv4(2))^2 + (z-sv4(3))^2)^0.5 + t == prange(4), x, y, z, t);