Based on the conditions of minimum zone method

a non-linear programming model is build for spatial straightness error evaluation. This non-linear model is further proved

in essence

to be a multi-target optimization problem

and can be transformed into a single-target optimization problem. A unified and efficient successive quadratic programming method ( SQP algorithm) is proposed to solve these model. As the non-linear programming model is convex and SQP algorithm can retain such non-linear information

the method has very loose requirements on initial parameters. Also

this method is very stable

reliable and highly efficient in optimization. Several experiments of Spatial straightness error evaluation fit the requirements for convex programming’s global optimization very well which has proved these conclusion.