Abstract: The direction cosine location method which is used in traditional optical geometric intersection is simple, so it is widely used in engineering practice. But this method is greatly influenced by the geometric relationship, and cannot inhibit the measuring error, so its positioning accuracy is unsatisfactory. In addition, it cannot be used to compute the locations with more than three stations at a time. A new positioning method with multi-optical theodolites is proposed based on Hermite function restriction. This method can be called function restricted EMBET method. This method uses Hermite function to express the positioning parameters to compress the number of parameters to be estimated, and meanwhile the measuring elements of optical theodolite can be expressed. The measuring equation can be formed by measuring data of multiple measuring elements. Based on least square criterion, the positioning parameters are obtained by computing the combined equation, and the system errors of measuring elements are calibrated. Through the calculation of simulated example, the function restricted EMBET method is compared with the direction cosine location method. The result shows that the function restricted EMBET method is more accurate and more practical.

Key words: optics, optical theodolite, time sequence relevance, function restriction, Hermite function, error model best estimate of trajectory