The Research On The Network Optimization And The Three-Dimensional Positioning Of The Target In Wireless Sensor Networks

The wireless sensor network is one of the 21 most influential technologies in the 21 st century,which belongs to multi-disciplinary intersection and involves in the frontier of computer,communication and mathematics.It is a kind of self-organizing data processing network by deploying a large number of sensor nodes,which are mainly used in the collection and transmission of the special monitoring information.Data collection,quantification,aggregation and transmission can be realized through the dense deployment of sensor nodes in the network.As a modern intelligent network,the application prospect of the wireless sensor networks is very broad,such as: military applications,internet of things,environmental monitoring,modern transportation(the sharing of bicycles in the last two years),convenient express delivery,modern medical treatment,industrial application,space exploration.In this dissertation,we focus on the object three-dimensional positioning,the robust data transmission path optimization and the topology control in wireless sensor networks.The main achievements are as follows.1.Note that the data transmission is easily affected by the external instability factors in wireless sensor networks,especially the attacks of malicious nodes.In the construction of wireless sensor network topology,first of all,the malicious nodes need to be detected and removed from the network.By using the ant colony algorithm,the optimization path method is applied to the topology construction in the wireless sensor network.In the establishment of the probability formula in the node path selection,the residual energy of nodes,the distances between nodes,data redundancy,link security and other factors are considered comprehensively.And finally an intelligent,safe,efficient and robust data transmission path optimization algorithm based on the ant colony algorithm is presented.The MATLAB simulation results show that the proposed algorithm prolongs the lifetime,reduces the load of the nodes and also improves the link successful rate of the network obviously.2.Aiming at the transmission of heterogeneous data in heterogeneous networks,a topology optimization algorithm of heterogeneous wireless sensor networks based on local tree reconstruction is proposed,which can achieve better data transmission in the heterogeneous networks.Firstly,the algorithm divides the nodes of the network into different layers by their hops,and chooses a different number of nodes as relay nodes in different layers.Secondly,the nodes are set different initial energy in different layers.Because the packets of different nodes have different sizes,we adopt the corresponding data aggregation coefficients according to the actual data requirements of the network in data transmission.Lastly,the lifetime of the network is prolonged by real-time updating the topology of the tree during the data transmission.The simulations indicate that after the aforementioned three steps,the proposed algorithm both prolongs the lifetime of the heterogeneous networks and improves the nodes utilization effectively.3.Consider that the observed values of the radio signal arrival time are mainly affected by such the factors as non-line-of-sight propagation,which makes a lot of noises,that is positioning error.For the three-dimensional positioning of the target,we construct the modified least squares three-dimensional positioning model which can achieve accurate three-dimensional positioning in real scene.Based on the spatial distribution of the base station,an optimal base station selection strategy is proposed by using the spectral clustering.The simulations illustrate that the error of the proposed algorithm is smaller than those of other existing algorithms using the same simulation data,and the proposed algorithm has low complexity,fast convergence speed,and high practical application value.