# Design of OCC Indoor Positioning System Based on Flat Panel Light and Angle Sensor Assistance
## 1 Introduction  
Since the 21 st century, LED (light-emitting diode) technology has developed rapidly and is widely used in many fields. Its branch, visible light communication (VLC), uses visible light as a signal transmitting base station and has advantages that traditional wireless communication methods do not have, such as a rich spectrum, a green environment, no electromagnetic radiation, and a low cost, and it can be combined with lighting. Visible light positioning (VLP) technology is a classic application of VLC, and VLP technology inherits the advantages of VLC and is a popular technology in the field of positioning [1, 2].  
In outdoor positioning, the United States developed the Global Position System (GPS) for civil satellite positioning [3], which has become the mainstream positioning tool in society because of its meter-level positioning accuracy, high coverage, and complete functionality. However, GPS is difficult to be applied in indoor environments. Because the indoor complex environment interferes with the satellite signal and the signal is weakened in the indoor environment, it is difficult to achieve real-time positioning and the positioning error is large.  
Currently, common indoor positioning technologies include infrared positioning, ultrasonic positioning, Wi-Fi positioning, ZigBee positioning, Bluetooth positioning, ultra-wideband (UWB) positioning, and visible light positioning (VLP) [4]. Each of these positioning technologies and solutions has its own advantages and disadvantages, and the complexity of implementation and usage scenarios vary. Table 1 shows the comparison of the differences between various classical indoor positioning technologies in terms of positioning accuracy, implementation cost, environmental range, stability, and anchor point classification.  
As we can see, VLP is an important direction for the future development of indoor positioning technology because of its high positioning accuracy, low cost, and high interference resistance. Image VLP(i-VLP), whose receiver is an image sensor (IS), obtains information by photographing LED light sources and aids in precise positioning by photogrammetry, so it is also known as optical camera communication (OCC), and several studies [5; 6; 7] have used this method for indoor precise positioning. [PERSON] and [PERSON] have proposed the use of QR codes as identification information but rely on dual lights for localization [8; 9], and others have proposed a localization technique using a held flat panel light source but with improved circuitry [10].  
In this paper, an indoor information localization technique for basic flat panel light is proposed, incorporating a barcode to convey information, using a smartphone with an integrated image sensor as the signal receiver, constructing an OCC system, and designing algorithms to improve the localization accuracy of this system with the assistance of an angle sensor.  
The rest of this paper is structured as follows: Section 2 introduces the principle of this system design, Section 3 introduces the process of fuzzy positioning, Section 4 introduces the precise positioning algorithm assisted by angle sensors, Section 5 shows the experiments undertaken according to the algorithms in the first two sections and the analysis of the results, and Section 6 is the summary and conclusion of this paper.