基于RSSI测距的室内目标定位方法

Indoor targeting method based on RSSI ranging

针对既有的基于RSSI测距的室内目标定位系统在实际应用中存在的测距误差大,定位精度低,以及稳定性差的问题进行分析与改进,提供一种融合RSSI测距模型实时修正与定位结果辗转优化的室内目标定位方法,改进之处主要在于:在测距阶段,根据记录的信标间真实距离和RSSI衰减值对RSSI测距模型参数进行反向实时修正;在定位阶段,使用极大似然估计法初步确定移动目标的当前位置,而后将目标点坐标与测距值都作为未知数使用牛顿迭代法求最优解。实验证明,相对于既有的典型RSSI室内目标定位方法,所提出的方法首先提高了测距精度,进而提高了定位算法对测距误差的鲁棒性,从而整体上可有效提高室内目标点的定位精度。

Aiming at the disadvantages of the existing indoor targeting methods based on RSSI ranging in the practical application,such as big ranging error,low positioning accuracy and poor stability,analysis and improvement are carried out to provide an indoor target positioning method coalescing real-time RSSI ranging model correction and original localization result successive optimization. The main improvement includes that in the distance estimation step,the RSSI range model parameters are modified real-timely in reverse according to the actual distance and the RSSI attenuation value between each beacon pairs; in the position calculation step,Newton method is added to optimize the target position after the initial position of an target is derived using maximum likelihood estimation method,and the target’s coordinates and the target-beacon distances are all regarded as unknowns in the equation set. The simulation shows that under the same network conditions,compared with a representative improved algorithm,our improvement can obtain higher distance estimation accuracy in the first step,and then,it can improve the robustness to distance estimation error in the second step. Thereby,the improvement can improve the average target localization accuracy in the network.