CDMA modulation based 3D positioning method of visible light communication (VLC)

Abstract

The invention discloses a CDMA modulation based 3D positioning method of VLC. Multiple reference point light sources exist in a traditional visible light indoor positioning system, intersymbol interference is caused among the reference point light sources due to different transmission paths, and the precision of indoor positioning is influenced greatly. Optical signals which are overlapped in both time domain and frequency domain originally can be separated by utilizing orthogonality of spread spectrum coding. A positioning position area is determined according to ID position information obtained by a positioning terminal, and the coordinate of a positioning position is determined according to a light intensity attenuation factor of a reception end by utilizing an RSS triangular positioning algorithm. Compared with the traditional VLC positioning technology, the positioning precision is improved, the system is simple and stable and does not need synchronous emission, and the system has a wide application prospect.

Description

technical field [0001] The invention relates to a visible light communication positioning technology, in particular to a CDMA modulation-based visible light communication three-dimensional positioning method. Background technique [0002] In recent years, Indoor Positioning Systems (IPS) has become the hottest topic. This technology is beneficial to indoor services for humans and intelligent robots, and can provide users with location information and push corresponding service information. Global Positioning System (Global Positioning System, GPS) is a good navigation system for outdoor applications, and has a wide range of applications in mobile phone map services, car navigation, ships and aircraft. However, due to multipath fading, electromagnetic shielding effects, and interference from other wireless devices, traditional outdoor positioning technologies such as GPS have poor signal coverage indoors, and there are large positioning errors when used for indoor positioning...

AI Technical Summary

Problems solved by technology

However, these positioning systems have the following disadvantages: (i) more signal access points need to be reconfigured, which increases the cost of the indoor positioning system and the difficulty of control; (ii) due to the uneven spatial distribution of wireless signals and the stability It is not high, and the fluctuation of the positioning point at the same point is strong, which limits the accuracy of positioning; (iii) These wireless positioning technologies will generate electromagnetic interference. On the one hand, they will be affected by other wireless services and affect the quality of positioning , on the other hand, it is not suitable for electromagnetic sensitive occasions such as hospitals and airports

Further, when triangulation algorithm is generally used to estimate the positioning distance based on received signal strength based on Intensity Modulation and Direct Detection (IM/DD), it is necessary to know the posi...

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