The aims of the present investigation were:（a）to develop the method for three-dimensional space reconstruction using the simplified calibration in which already-known points like intersections of lines on a volleyball court and points on antennae are utilized as control points for calibration and（b）to investigate the accuracy and characteristics of the three-dimensional coordinates estimated by this method. Consequently, this method has characteristics as follows:（1）the method obtains less or equal accurate estimation in three-dimensional coordinates compared to a general calibration,（2）the accuracy of estimated X or Y coordinates in the position close to the outer border of the court is relatively lower than that in the center of the court,（3）the lower position close to the outer border of the court and the higher position in the center of the court indicate higher accurate estimated coordinates and（4）the position in an analytical area has an influence on the accuracy of estimated coordinates. Along with an understanding of the above characteristics in this method, the method using alreadyknown points is useful as a substitution of a general calibration without utilizing the positions in an analytical area where three-dimensional coordinates are over- or underestimated.
