Information of an instrument point of a surveying apparatus is more simply and easily acquired. Positioning data that is obtained by a first surveying apparatus in which exterior orientation parameters are known, and positioning data that is obtained by a second surveying apparatus in which exterior orientation parameters are unknown, are received. The first surveying apparatus and the second surveying apparatus are configured to obtain positioning data by measuring multiple positions of a UAV that is flying. A piece of positioning data is acquired from the positioning data of the UAV obtained by the first surveying apparatus and from the positioning data of the UAV obtained by the second surveying apparatus. These pieces of positioning data are in a correspondence relationship. The position of the second surveying apparatus is calculated based on the pieces of positioning data that are in the correspondence relationship, by a method of resection.