A simple and low cost angle measurement system for mobile robot positioning

Positioning is a fundamental issue in mobile robot applications that can be achieved in multiple ways. Among
these methods, triangulation with active beacons is widely used, robust, accurate, and flexible. Our paper presents a new active beacon-based angle measurement system for indoor navigation using infrared signals. We propose a complete system for global positioning on a 2D plane based on the following parts: (1) a mirror, a lens, and a light guide, (2) a mini stepper motor and its controller, (3) an infrared receiver (TSOP7000), (4) a PIC microcontroller, and (5) three infrared beacons. The acquisition rate is 10 [Hz] and the accuracy is about 0.1 [degree]. The entire sensor is contained in a (8 X 8 X 8) [cm3] volume. The key innovation is the use of a cheap and simple infrared receiver as the main sensor for the angle measurement principle. The beacons too are simple cheap infrared LEDs. Furthermore, the system requires only one infrared communication channel, and no synchronization between the beacons and the robot is required.