A navigation system includes sensors to detect a moving direction and location of a mobile body. The first rotatable assembly includes a rotary member rotatably assembled in the base seat, a steady member and an elastic member non-rotatably received in the base seat, and a fastening member. A bore head is aligned with the predetermined orientation. The reconstructed sound source signals are obtained via solving the relational expressions and input into a speaker array arranged outside the area to establish the reconstructed sound field in the area. The system involves a scheme in which the fingers are used for consonants and the thumb for vowels, with fingers and thumb used together for voiced consonants.