基于分布式自适应偏转次梯度投影算法的气体源点定位研究

Research of Locating Gas Source Based on Distributed Adaptive Deflection Projected Subgradient Algorithm

针对无线传感网络中的气体源点定位问题，采用自适应次梯度投影定位算法（APSM）来逼近气体源点位置。由于实际气体浓度测量值受噪声干扰，导致APSM定位算法在估计源点位置时难收敛，并且计算耗时长，于是对其迭代搜索方向进行修正，并结合无线传感网络分布式计算的特点，提出一种分布式自适应偏转次梯度投影定位算法（DADPSM），该算法以有风时气体浓度衰减模型为基础，以DADPSM算法为核心，利用偏转次梯度方向代替原次梯度，以偏转次梯度投影的超平面作为搜索区域来进行松弛投影，对节点获取的气体浓度信息进行分布式计算，从而估计出气体源点位置。仿真实验表明，该算法收敛快、定位误差小，并且网络能耗少。

In view of gas source localization in wireless sensor networks, an adaptive projected subgradient method （APSM） is firstly introduced to estimate the gas source position. However, the APSM for locating is difficult to converge and consumes much time because of the concentrations corrupted by noise. So a distributed adaptive deflection projected subgradient method （DADPSM） is proposed for modifying the iteration search direction and combing the characteristic of distributed calculation in WSN. Under the attenuation model of a gas source in the wind field, this algorithm could process the distributed information by DADPSM, the deflection subgradient direction is used in place of original gradient and the deflection subgradient projection hyperplanes is applied as the searching areas in the process of relaxed projection to achieve the gas source localization. Simulation proves that this algorithm can provide good convergence property, locate the gas source accurately, and save large amount of energy.