GPS system (Guidance Positioning System) is an original system of guidance. This is a simple navigation system for projecting the theoretical position of the puncture needle in the ultrasound plane. The guidance system consists of a receiver and two motion sensors. The receiver is connected to the system. A motion sensor is incorporated into the end of the needle. Another motion sensor is located within the ultrasound probe. The relative positions and the axes of the needle and the ultrasound probe are transmitted with coordinates in three dimensions.