Relative localization system and method using ultrasonic sensor

PURPOSE: A relative position estimation system and a method thereof based on an ultrasonic wave sensor are provided to estimate location and moving direction of an object. CONSTITUTION: A position estimation system includes a first mobile robot(10), a second mobile robot(20) and a server unit(30) . The first mobile robot is installed with a plurality of ultrasonic wave sensors and acquires distance information of an object in the surroundings. The second mobile robot is installed with a plurality of ultrasonic wave sensors and acquires distance information of the object in the surroundings. The server unit receives acquired distance information from the plurality of ultrasonic wave sensors installed in the first mobile robot and the second mobile robot. The server unit determines a pair of ultrasonic wave sensors having the same distance measurement value in the plurality of ultrasonic wave sensors installed in the first mobile robot and the plurality of ultrasonic wave sensors installed the second mobile robot and estimates a relative position and direction between the first mobile robot and the second mobile robot based on the determined pair of ultrasonic wave sensors. [Reference numerals] (12,22) Ultrasonic sensor; (14,24) Electronic compass; (16,26) Odometer; (18,28) Control unit; (30) Server unit;