The Localization Algorithms And Research Of Realization Based On ZigBee

Localization technology is one of the important supporting technology of wireless sensor network, and also a hot topic of studying currently. In order to take corresponding measures and emergency rescue measures when it is handy, the happen of some emergencies often need to know their position information, therefore, which need to have a relatively complete positioning system and a series of effective algorithm theories, and research of localization algorithms directly affect whether the positioning system can achieve ideal location accuracy. So the study of localization algorithms is a very valuable thing, it has profound significance in the actual application.According to the classifications of the positioning methods, it can be divided into range-based and range-free, and also incremental and concurrent. This paper studies the localization methods which are based on the distance and the incremental positioning methods. The essence of incremental localization method is based on distance, they all need to measure distance and measurement of distance is based on RSSI(Received Signal Strength Indication) ranging principle.This paper first introduces the development and deficiency of positioning technology in the domestic and overseas, and illustrates important practical significance of the positioning technology. Secondly, it introduces ZigBee wireless technology and related theory, ZigBee is a new technology that developed in recent years, and has many advantages in the wireless sensor network applications, wireless location based on ZigBee technology is the focus of this paper. Then the common theories of the localization algorithms are detailed in this paper, mainly introducing the principles and processes of localization algorithms based on distance, such as TOA(Time of Arrival)、TDOA(Time Difference of Arrival)、 RSS(Received Signal Strength) and AOA(Angle of Arrival) localization algorithms. This paper puts forward two special positioning algorithms based on ZigBee positioning technology and algorithm, which is two points localization algorithm and improved increasing localization algorithm. Positioning principle is based on the collected RSSI value, through the theory or experience ranging model will be converted into the distance value, then according to the proposed algorithms which can find out the coordinates of the unknown points. Considering highway and underground and other special environment, and putting forward the two-point algorithm of the reference nodes which are unilateral arrangement, which on the one hand can save cost, and on the other hand can improve the efficiency of positioning; But in large scale area nodes localization need to know position information of more anchor nodes, it is complicated if uses the artificial measurement, so this paper puts forward a gradually increasing positioning method that the reference nodes are as locating nodes, and only when the initial positioning, certain reference nodes are chosen as the known location of the nodes, but increasing localization will cause the influence of the accumulated errors, in this basis, so the article puts forward an improved weighted least squares. Through the simulation of MATLAB, the proposed algorithms are effective positioned.At last, to implement the algorithms combined with ZigBee hardware in practical application. Positioning research based on ZigBee technology mainly is uses CC2430module, which the biggest characteristic is that the cost and power consumption are low. The whole positioning system is composed of reference nodes, mobile nodes and gateway, and for each node, the compose of hardware and design of software based on singlechip processor have be described in detail, RSSI values were collected based on the experimental environment, combing with the theory of lateral distance model, using least squares fitting method to get parameter values for A and n, then using trilateration and two-point methods to positioning and compare the results in the experiment. Design of PC software uses MATLAB GUI in the experiment, obtaining the experimental data with a serial port communication. The experimental results show that the proposed algorithms can achieve the desired effect of positioning, the whole positioning system is well tested by the experiment environment.