Local Positioning System for Indoor Robot Navigation

Abstract

Local positioning systems for indoor robot navigation are in a developing stage using different technologies and algorithms. Many researchers and engineers have focused in improving the accuracy of the local positioning systems. The main focused era of local positioning systems is to predict the position of a robot using known landmarks or transmitting devices located in the indoor system. Most of the local positioning systems are in the experimental stage and some are developed as marketable products after testing under different conditions. Matter of fact exact positioning of a robot in an indoor environment is a fundamental problem in robot navigation. These local positioning systems are helpful in such environments where global positioning systems are not functional to provide accurate information of the position of the robot. This paper describes a methodology that can be used in indoor navigation to determine the position of a robot. In the system developed ultrasound is used as the communication method. The system designed, consists with several transmitters which can emit ultrasound and a mobile receiver which is capable in receiving the transmitted sound. The ultrasound consists with frequencies above 20 kHz. These frequencies are beyond the sensitivity range of the human ear. Mostly these kind of signals are used by bats to find their path to fly avoiding the obstacles. In the developed system three ultrasound transmitters are used as the landmarks of the positioning system. One transmitter acts as the reference terminal in initiating the determining the process of the positioning system. The accuracy of the system is depend on the number of transmitters have been used. The minimum resolution of the developed system is 5 cm and tested up to 100 cm range in an obstacle free environment.