Key Technology Research On Home Security System Based On Wireless Sensor Network

With the rapid development of social economy, People's standards of living is improving gradually. Meanwhile,the demands for home security are also increasing.The home security system based on wireless sensor network can be achieved on the family environment monitoring.It is of great significance to establish comfort?environmental protection?energy saving and safe living space.This paper makes a further investigation on home security and focuses on two kinds of anti-intrusion and anti-fire precaution objects.Firstly,this paper researches the staff invasion and alarms by infrared sensor and sound sensor and uses the TDOA algorithm to localize the sound source. In order to obtain ideal time delay estimation, an anchor node selection and time delay estimation strategy are proposed.This strategy can pick out the optimal anchor nodes involved in localization. Aiming at problems of multiple solution in solving process, a regional judging rule is put forward to solving the equations after multiple judgment of the target location. This rule can reduce the amount of system calculation under the premise that does not affect the positioning accuracy. As the experiment shows that the method has small amount of calculation and high precision and good positioning effect.Secondly,single sensor is difficult to meet the problem of fire warning,the way of multi-sensor collaboration is applied to joint warning.In order to obtain stable and reliable monitoring data,Gaussian filter?recursive average filter and kalman filter are used to processing the data.In addition,the multi-sensor data fusion technology is applied in fire detection and the D-S evidence theory is adopted to improve the fusion. In view of the problem that Dempster-Shafer theory of evidence can not effectively deal with the issue of conflicting evidence,a weight allocation method based on distance of evidence is proposed to allocate weight of each evidence.Then it modifies the original evidence and recalculate the probability distribution. Eventually,it uses the D-S combination rules to fuse the new evidence. As the experiment shows that the new method achieves good fusion effect and can effectively deal with the issue of conflicting evidence.In the end,both PC and mobile terminal operation interface are developed according to the needs of different users.It can makes both long-range and short-range users obtain information on the household environment in real time.Sequentially,it can gain better perception of family security.