1. A computer-readable recording medium that stores therein a program for locating a moving object by using a plurality of images taken outside the moving object with a plurality of cameras mounted on the moving object, the program causing a computer execute: detecting a position and a direction for a first marker, a second marker, and a third marker contained in the images; identifying a first origin trajectory relating to an unknown origin position for the moving object based on the first marker and the second marker; identifying a second origin trajectory relating to the unknown origin position based on the second marker and the third marker; locating the unknown origin position at coordinates of an intersecting point of the first origin trajectory and the second origin trajectory; calculating a first virtual optical center having a field of vision that includes the first marker and the second marker, and a second virtual optical center having a field of vision that includes the second marker and the third marker; calculating a first inter-marker angle between the first marker and the second marker having a vertex at the first virtual optical center and a second inter-marker angle between the second marker and the third marker having a vertex at the second virtual optical center; identifying the first origin trajectory such that the first inter-marker angle, a distance between the first virtual optical center and the unknown origin position, and an angle formed between a line from the first virtual optical center to the second marker and a line from the first virtual optical center to the unknown origin position remain constant; and identifying the second origin trajectory such that the second inter-marker angle, a distance between the second virtual optical center and the unknown origin position, and an angle formed between a line from the second virtual optical center to the third marker and a line from the first virtual optical center to the unknown origin position remain constant.