Abstract: A boring head of a boring tool for boring the ground includes a device for detecting inclination of the boring head therein. The device includes a roll angle sensor and a pitch angle sensor. The roll angle sensor detects an angular position of the boring head in a roll direction and outputs a roll angle detecting signal. The pitch angle sensor detects an angular position of the boring head in a pitch direction outputs a pitch angle detecting signal. A signal modulating circuit converts the roll angle detecting signal and the pitch angle detecting signal into a serial signal and modulates the serial signal. An output circuit receives the modulated serial signal and outputs a magnetic field which is receivable by a receiver located on the ground and which permits determination of the roll angle and the pitch angle of the boring head.

Abstract: A boring head for boring the ground includes a housing of substantially cylindrical configuration. An electric power source, a coil, a switch and an oscillator are mounted within the housing. The coil generates an electromagnetic wave, and the oscillator is connected with the power source, the coil and the switch. The switch is operable to be switched according to an angular position of the housing in a circumferential direction as to whether the angular position is within a predetermined range. The configuration of the electromagnetic wave generated by the coil can be changed through the switch according to the angular position of the housing.