The growth of the Internet of Things has increased demand for location information services, but existing indoor positioning technology has limitations. The purpose of this paper is to discuss indoor positioning with a single audio base station and to propose an indoor positioning method based on signal strength. The proposed method is simple to use on smart phones, and the base station is straightforward to deploy. The base station transmits digital amplitude modulated signals in multiple directions using this method. Prior to the test, a database is created with the signal strengths measured at multiple points throughout the area to be evaluated. During the test, the terminal measures the signal strength and compares it to the database to determine the spatial position. Indoor dynamic and static tests are conducted to evaluate the method’s performance. The test results demonstrate that the positioning method is highly accurate and will meet the requirements for indoor location-based services.