For quality assurance during manual handling processes in industrial assembly and logistics, systems for the recording of the position(s) and orientation(s) of work pieces and tools are used. For this purpose, robust, opto-acoustic systems based on unilateral distance measurement through time-of-flight measurement prevailed. Ultrasound transmitters are sending signals one by one in a time-division multiple access (TDMA) mode. Due to the ultrasound propagation time, only a limited amount of tools can be tracked permanently. Thus, the project goal is the development of a code-division multiple access (CDMA) based indoor localization system which allows the permanent, simultaneous transmission of code-modulated ultrasound signals for positioning. Hence, the limitations of TDMA systems regarding the amount of trackable tools can be overcome.