Sound localization system based on time difference of arrival with considerable power saving

WANG Yi-ping， WANG Hao， WU Heng， WU Yang-bo
（Faculty of Information Science and Technology， Ningbo University， Ningbo 315211， China）

Abstract： Aiming at the high power dissipation and low precision problems of the localization of a moving sound source in the weak noise environment，a technology based on time difference of arrival（TDOA）was applied to locate the moving sound source，which had considerable power saving. After the analysis of mathematical modeling and theoretical means of the TDOA method in an analog application，the corresponding relationship between the delivering，receiving and identification of the sound source was established. A method was presented that a path of narrow pulse with a constant duty cycle produced by C8051F330 SCM was changed into a series of cyclical data through FPGA counted the effective width of the source signal，which was processed by a set of pickup devices，then it was transported to the core processor named C8051F020 SCM. To raise the precision of the system，the method of moving-average filter and throwing algorithm was utilized by the SCM so that it was able to lower parts of valid signals outside. Based on theoretically calculation and experiment，three aspects of the following were evaluated，including the power dissipation of the moving sound source，the accuracy of the system and the function of showing tracks. And two models of the setting were tested，which had differences in the time of the localization. The results indicate that，the power dissipation of the moving sound source is 50.1 mW and the maximum error of this system can reach 2.6 cm with the advantage of considerable power saving，excellent stability and high precision，and the tracks of the moving sound source can be shown timely through LCD.
Key words： sound signals localization； considerable power saving； time differece of arrival（TDOA）； single chip microcomputer（SCM）； field programmable gate array（FPGA）