In frequency division duplex systems, it is extremely difficult to position the receiver (Rx) that belongs to another system, defined as the third-party Rx, because the sensors usually do not know which band the Rx uses for reverse transmission. In this letter, we propose a new method to position the third-party Rx based on the transmitted signal of the third-party transmitter (Tx). In particular, our method exploits the close-loop power control between the third-party transceivers because the Rx location determines the signal-to-interference-plus-noise ratio (SINR) of the Rx and the SINR further determines the transmission power of the Tx. Therefore, by measuring the transmitted signal of the Tx, the sensors are able to position the Rx. Simulation results indicate the effectiveness of the proposed method.