| Location services are an integral part of life, and people increasingly demand for indoor location services. The increasing demand for indoor location services has prompted the rapid development of indoor positioning technology. In this wave of development, many indoor positioning technologies have been developed, for example, WiFi based indoor positioning technology, Bluetooth Based indoor positioning technology and geomagnetic based indoor positioning technology, etc..Although the above indoor positioning technology has been able to achieve indoor positioning requirements, but from the positioning accuracy, although slightly higher than the Bluetooth indoor positioning technology, indoor positioning technology based on the other, but there are still great positioning error, basically in error distance of more than 3m. And the indoor positioning technology based on WiFi and indoor positioning technology based on magnetic susceptible to interference from external factors, although the Bluetooth signal anti-interference ability stronger, but the Bluetooth transmitter purchase and deployment environment is very large, requires a lot of hardware equipment investment. Considering the above problems, this paper studies the visible light indoor positioning technology for intelligent terminal.In recent years, with the light emitting diode (Light Emitting Diode,LED) and the development of mature technology, LED lamp can quickly replace incandescent and fluorescent lamps as lighting tools daily, in this case, all use LED lights as a lighting tool for indoor environment, are visible indoor positioning the scene, visible as indoor positioning media,has the advantages of stable light source, less vulnerable to external interference. In this paper, the accuracy and stability of indoor positioning.First, this article uses the external control frequency way, causes each LED lamp to transmit in own independent channel, thus can prevent the indoor environment light the disturbance and the LED light mutually collides with each other. Combined with the FFT algorithm, the intensity of LED light measured by the final intelligent terminal is more accurate,which reduces the probability of indoor positioning error caused by the collision between environmental light or visible light transmission.Secondly, through the visible light communication (Visible Light,Communication, VLC) technology, to make each LED lamp visible light to carry digital information related, due to visible light transmission,channel gain, combined with the propagation model can be determined by calculating the optical channel gain, channel gain constant can be calculated between the LED lamp and the intelligent terminal receiver distance. Finally, this paper studied the two-dimensional positioning algorithm, and extends to the three-dimensional localization algorithm in 3D space, by establishing the relationship between the mobile phone and the indoor coordinate system coordinate system, finally obtain the indoor location information. On this basis, this paper further studies the three side positioning algorithm, and through the weighted and least squares fitting method, reducing the indoor positioning error range.The simulation results show that the visible light indoor positioning technology for the intelligent terminal, can not only realize the demand for indoor positioning, and on this basis can make the error range of basic maintenance in 0.04m ? 0.06m, greatly improving the indoor location estimation accuracy and stability. |
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