Wireless Monitoring Network System For Indoor Light Environment

Indoor light environment monitoring plays an important role in light environment assessment and design, and is an important part of enhancing the indoor environment. However, lots of challenges are brought into it because of inherent optical properties and lighting design factors. In order to improve the method of monitoring, a precision optical sensor based distributed wireless monitoring network system for indoor light environment is designed in this paper, which is significant in both research and application.Based on the feature of application and existing technology, a integral indoor light environment monitoring system is proposed in this thesis, which integrates wireless communications, multi-parameter high-precision optical detection, and high-performance self-localization technologies. The innovations of this thesis are as follows:First, this thesis designs the multi-parameter and high-precision light enviroment sensor module with wireless network interface, which is the platform of wireless monitoring network. By analyzing the requirements of indoor light environment monitoring, and integrating wireless sensor network technology with optical detection technology, the high-precision light environment sensor module is designed, which matches with spectral luminous efficiency of the human eyes for photopic vision and combines with the wireless data transmission. The module can detect the light environment information systematically and precisely, then transmit and collect the information through a radio link, which satisfies the comprehensive requirements of wireless communications, multi-parameter monitoring, distributed real-time detection and low power.Second, the multi-directional ultrasonic detector based self-localization method is designed. Based on the TDOA (Time Difference of Arrival) ranging mechanism, the geometrical relations of same ultrasonic detector module are associated with signal reception time to improve positioning accuracy and ensure omni-directional receiving. And the main error sources of ultrasonic distance measurement is also optimized and compensated. Meanwhile, by using multi-directional ultrasonic detector, multiple sets of data are introduced, so the localization can still be finished in the case of rare number of beacon nodes. And in the case of sufficient beacon nodes, the optimization search based maximum likelihood estimation algorithm is used to ensure the accuracy of self-localization.Third, establish the whole indoor light environment monitoring system based on the self-localization optical sensor module. According to the features of monitored environment, a integral structure of network is built, which incorporates node deployment, network set-up, self-localization, and light environment information collection and uploading. And the performance of system is analyzed to be used in distributed indoor light environment monitoring.