In this paper, we propose a novel real time information gathering method based on frequency and time mapping for wireless sensor networks. Traditional information gathering method by using packets based data exchange requires long period for information gathering from many sensor nodes. In the proposed method, each sensor node converts sensed data and their position to a subcarrier-frequency of OFDM signals and two time-slots, respectively. Then, all sensor nodes send tone signals according to the assigned subcarrier-frequency and time-slots. The sink node receives multiple tone signals sent by the sensor nodes and estimates the correct information from frequency and timing of the received signals by utilizing a spatial correlation of observed target or the position of sensor nodes. By using the proposed method, we can gather high precision sensing information with the position of the sensor nodes in a short time.