Department of Electronics, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
Sensors (Basel). 2019 Feb 6;19(3):670. doi: 10.3390/s19030670.
This paper proposes an algorithm for calibrating the position of beacons which are placed on the ceiling of an indoor environment. In this context, the term calibration is used to estimate the position coordinates of a beacon related to a known reference system in a map. The positions of a set of beacons are used for indoor positioning purposes. The operation of the beacons can be based on different technologies such as radiofrequency (RF), infrared (IR) or ultrasound (US), among others. In this case we are interested in the positions of several beacons that compose an Ultrasonic Local Positioning System (ULPS) placed on different strategic points of the building. The calibration proposal uses several distances from a beacon to the neighbor walls measured by a laser meter. These measured distances, the map of the building in a vector format and other heuristic data (such as the region in which the beacon is located, the approximate orientation of the distance measurements to the walls and the equations in the map coordinate system of the line defining these walls) are the inputs of the proposed algorithm. The output is the best estimation of the position of the beacon. The process is repeated for all the beacons. To find the best estimation of the position of the beacons we have implemented a numerical minimization based on the use of a Genetic Algorithm (GA) and a Harmony Search (HS) methods. The proposal has been validated with simulations and real experiments, obtaining the positions of the beacons and an estimation of the error associated that depends on which walls (and the angle of incidence of the laser) are selected to make the distance measurements.
本文提出了一种校准放置在室内环境天花板上的信标的位置的算法。在这种情况下，校准一词用于估计与地图中已知参考系统相关的信标的位置坐标。一组信标的位置用于室内定位目的。信标的操作可以基于不同的技术，例如射频 (RF)、红外线 (IR) 或超声波 (US) 等。在这种情况下，我们对构成放置在建筑物不同战略点上的超声波定位系统 (ULPS) 的几个信标的位置感兴趣。校准方案使用激光测距仪测量的信标到相邻墙壁的几个距离。这些测量距离、建筑物的矢量格式地图和其他启发式数据（例如信标所在的区域、距离测量到墙壁的近似方向以及地图坐标系中定义这些墙壁的线的方程）是所提出算法的输入。输出是信标位置的最佳估计。对所有信标重复该过程。为了找到信标位置的最佳估计，我们已经实现了基于遗传算法 (GA) 和和声搜索 (HS) 方法的数值最小化。该提案已经通过模拟和实际实验进行了验证，获得了信标的位置和与所选择的用于进行距离测量的墙壁（和激光的入射角）相关的误差的估计。
