This paper proposes a novel pose system for mobile robots, which can provide cheap and robust solution for pose estimation. Its pose estimation approach is based on at least two optical sensors. The pose system also presents a method for system calibration to improve accuracy. There are several advantages with respect to this system: (1) the measurement from the optical sensors is insensitive to slipping and crawling; (2) this pose estimation system is independent from the kinematics of the robot; (3) compared to incremental encoders, our system is a low-cost and flexible solution for indoor mobile robots. Some simulations have been done to validate our system