Error Compensation for Cricket Indoor Location System

Cricket is a fine-grained indoor location system utilizing beacons transmitting both ultrasound and radio wave signals. However, the system accuracy is greatly impacted by the relative angle and distance between the beacon and listener. This paper proposes a low cost method to improve the system precision by means of incremental error compensation. The ultrasonic detecting error, which directly affects the accuracy of time-difference-of-arrival (TDOA), is first analyzed and verified via experiments. Then an error compensation method is designed based on total least squares (TLS) to further improve the cricket´s localization performance. Experimental results show that the average error of localization is reduced to 5.60 cm with compensation, compared with 9.06 cm of the original cricket method. The standard deviation of the errors is reduced from 7.80 cm to 3.99 cm. This method lays a foundation for further improving the existing ultrasound-related distance measurement method.