Performance comparison of different codes in an ultrasonic positioning system using DS-CDMA

In this work, several code division multiple access encoding schemes are evaluated for their application in ultrasonic sensory systems based on the determination of times-of-flight. Proper encoding improves the performance of such systems in terms of noise immunity, capability of simultaneous measurements and precision in the distance measurements. Important applications that include encoded ultrasonic signals are obstacle detection, local positioning in ubiquitous computing or non-destructive testing. Here, Kasami, Golay and Loosey synchronous codes are experimentally tested in a privacy-oriented ultrasonic local positioning system based on hyperbolic trilateration.