An accurate low-cost ultrasonic localization system is developed for automated nobile robots in indoor environments,which is essential for automatic navigation of mobile robots with various tasks.Although ultrasonic sensors are more cost-effective than other sensors such as Laser Range Finder(LR F)and visit,but they are inaccurate and directionally ambiguous.First,the matched filter is used to measure the distance accurately.For resolving the computational complexity of the matched filter,a new matched filter algorithm with simple computation is proposed.Then,an ultrasonic localization system is peoposed which consists of three ultrasonic receivers and two or more transmitters for improving position and orientation accuracy was developed.Finally,an extended Kalman filter is designed to estimate both the static and dynamic positions and orientations.Various simulations and experimental results show that the proposed system is effective.