Positioning Method for Various Indoor Sound Sources by Detecting Reception Time Difference using Cross-power Spectrum Phase Analysis and its Experimental Evaluation

あらまし 音波を用いた測位は高い精度が実現されているものの,測位のための音源として超音波やスペクトル拡散した音な ど,特定の音が用いられている.本論文では,実際の利用環境である室内居住空間における各種音源の発生位置を明らかにする ことを目的とし,TDOA(Time Difference Of Arrival:到達時間差)法と CSP(Cross-power Spectrum Phase analysis:白色化相互相 関)法を用いた音源を問わない測位法を提案し,実験的に検証する.音波を受信する各受信点から参照点とする受信点を定め, その点と各受信点での音波の受信時間差を CSP 法で求める.その検出結果と設定している受信点の位置から音源の位置を算出 する.実際の利用範囲を考慮した広さの室内環境内(約 5m×4m の範囲)の天井に 30個の受信点を設定した実験系を構築した. まず,参照点を決定する方法を検討し,実験によって確認した.それに基づいて,実際への適用を考慮し,電子レンジの動作音, アラーム音源である火災報知器,移動履歴のモニタ,移動制御の観点からドローンの飛行音を取り上げ,測位実験を行った.各 音源の特性によって測位精度は異なるものの,数 cm から数十 cmの範囲内の実利用が可能と考えられる測位精度が得られた結 果を示す. Abstract Although positioning using sound waves has achieved high accuracy, specific sounds such as ultrasonic waves and spectrumspread sounds are used as sound sources for positioning. The purpose of this paper is to clarify the location of various sound sources in an indoor living space, which is the actual usage environment. We propose a positioning method using TDOA (Time Difference Of Arrival) and CSP (Cross-power Spectrum Phase analysis) method and verify it experimentally. A reference point is determined from the reception points that receives a sound wave, and a difference in reception time of the sound wave between that reference point and each reception point is obtained by the CSP method. The position of the sound source is calculated from the detection result of the reception time difference and the position of the set reception points. An experimental system was constructed in which 30 reception points were set at a ceiling in an indoor environment (in the range of about 5m x 4m) with an actual usage range. In the beginning, the method of determining the reference point was investigated and its validity was confirmed by experiments. Based on this method, the authors conducted a positioning experiment by considering the actual application using microwave oven operation sound, fire alarm as alarm sound source, and drone flight sound from the viewpoint of its movement monitor and control. Although the positioning accuracy differs depending on the characteristics of each sound source, the results of positioning accuracy considered to be practically usable within the range of several centimeters to several tens of centimeters were obtained by the experiment. キーワード 屋内測位, CSP, TDOA, 音源, アラーム音, ドローン Keyword Indoor positioning, CSP, TDOA, Sound source, Alarm sound, Drone