To obtain a receiver which detects whether interfering radio waves have been received or not so as to output a detection result.

The level of a received signal is detected from the output signal of a second BPF 8 by an independent system which is composed of a third IE amplifier 13, a level detection circuit 14 and an A/D converter 15 separately from that of the detection of positioning data. When an output is dropped due to interfering radio waves, its drop is output from a signal processing part 11 together with the positioning data. Thereby, a host apparatus such as a navigation apparatus which uses the positioning data to be output can recognize that the interfering radio waves are contained, and it can confirm the reliability of its positioning result. When a reception level which is detected by the level detection circuit 14 exceeds a preset level, the output of the positioning result may be inhibited.