Electronics Department, University of Alcalá de Henares, Escuela Politécnica. Ctra. Madrid-Barcelona, Km. 33,600, 28871 Alcalá de Henares, Spain.
Sensors (Basel). 2011;11(11):10398-414. doi: 10.3390/s111110398. Epub 2011 Oct 31.
Accurate coordinates for active beacons placed in the environment are required in local positioning systems (LPS). These coordinates and the distances (or differences of distances) measured between the beacons and the mobile node to be localized are inputs to most trilateration algorithms. As a first approximation, such coordinates are obtained by means of manual measurements (a time-consuming and non-flexible method), or by using a calibration algorithm (i.e., automatic determination of beacon coordinates from ad hoc measurements). This paper presents a method to calibrate the beacons' positions in a LPS using a mobile receiver. The method has been developed for both, spherical and hyperbolic trilateration. The location of only three test points must be known a priori, while the position of the other test points can be unknown. Furthermore, the paper describes a procedure to estimate the optimal positions, or approximate areas in the coverage zone, where the test-points necessary to calibrate the ultrasonic LPS should be placed. Simulation and experimental results show the improvement achieved when these optimal test-points are used instead of randomly selected ones.
在本地定位系统 (LPS) 中，需要准确的环境中放置的有源信标的坐标。这些坐标以及测量到的信标与要定位的移动节点之间的距离（或距离差异）是大多数三边测量算法的输入。作为初步近似，这些坐标通过手动测量（一种耗时且不灵活的方法）获得，或者通过使用校准算法（即，从特定测量中自动确定信标坐标）获得。本文提出了一种使用移动接收器校准 LPS 中信标位置的方法。该方法已针对球形和双曲线三边测量进行了开发。仅需事先知道三个测试点的位置，而其他测试点的位置可以未知。此外，本文还描述了一种程序，可以估计最佳位置或覆盖区域的近似区域，应在这些位置放置校准超声波 LPS 所需的测试点。仿真和实验结果表明，使用这些最佳测试点而不是随机选择的测试点可以提高精度。
