The UOS-100 ultrasonic positioning system is a tool tracking and error-proofing systems consisting of an ultrasonic emitter, at least three ultrasonic receivers, and a control interface. It enables users to precisely determine the position of a tool (or any other object) in three-dimensional space without the need for complex mechanical systems such as articulating arms. Error proofing demands that one knows which work piece a fastening tool is operating on. In the past this has been accomplished by footprinting the operation and restricting the motion of the tool to a single footprint. This system removes that limitation, and because the position of the tool is known, it is allowed to move freely over a much larger section of the conveyor.