1. Field of the Invention
This invention relates to bearing measuring systems.
2. Description of the Prior Art
Prior art bearing measuring systems are known in which directional antennas or a goniometer to which directional antennas are connected are rotated or the directivity of such directional antennas or goniometer is electrically rotated and the outputs of such antennas and a 90.degree. phase shifted output of a nondirectional antenna are combined to obtain a commonly termed cardioid characteristic while confirming information above a wave with a receiver for amplitude modulation. Also, it is known in the art to employ a system combining a system dealing with the measurement of the bearing of a frequency modulated wave and having a construction similar to that in the case of the afore-mentioned amplitude modulation with a system dealing with the information of the wave and having a construction similar to the usual frequency modulated wave receiver.
The afore-mentioned prior-art systems have required a special receiver for measuring the bearing by making use of a frequency modulated wave since it has been necessary to cause a 90.degree. phase shift of either the output of the nondirectional antenna or the outputs of the directional antennas. Accordingly, such systems have not been put to practical use.