In this work, the problem of localizing ground devices (GDs) is studied comparing the performance of four range-free (RF) localization algorithms that use a mobile anchor (MA). All the investigated algorithms are based on the so-called heard/not-heard (HnH) method, which allows the GDs to detect the MA at the border of their antenna communication radius. Despite the simplicity of this method, its efficacy in terms of accuracy is poor because it relies on the antenna radius that continuously varies under different conditions. Usually, the antenna radius declared by the manufacturer does not fully characterize the actual antenna radiation pattern. In this paper, the radiation pattern of the commercial DecaWave DWM1001 Ultra-Wide-Band (UWB) antennas is observed in a real test-bed at different altitudes for collecting more information and insights on the antenna radius. The compared algorithms are then tested using both the observed and the manufacturer radii. The experimental accuracy is close to the expected theoretical one only when the antenna pattern is actually omnidirectional. However, typical antennas have strong pattern irregularities that decrease the accuracy. For improving the performance, we propose range-based (RB) variants of the compared algorithms in which, instead of using the observed or the manufacturer radii, the actual measured distances between the MA and the GD are used. The localization accuracy tremendously improves confirming that the knowledge of the exact antenna pattern is essential for any RF algorithm.

在这项工作中，比较了使用移动锚点（MA）的四种无范围（RF）定位算法的性能，研究了定位地面设备（GDs）的问题。所有研究的算法均基于所谓的“听/不听”（HnH）方法，该方法允许GD在其天线通信半径的边界处检测MA。尽管此方法简单易行，但其准确性方面的有效性仍然很差，因为它依赖于在不同条件下连续变化的天线半径。通常，制造商声明的天线半径不能完全表征实际的天线辐射方向图。在本文中，商用DecaWave DWM1001超宽带（UWB）天线的辐射方向图可在不同高度的真实测试台中观察到，以收集有关天线半径的更多信息和见解。然后使用观察到的半径和制造商的半径来测试比较的算法。仅当天线方向图实际上是全向时，实验精度才接近预期的理论精度。但是，典型的天线具有很强的图案不规则性，从而降低了精度。为了提高性能，我们提出了比较算法的基于范围（RB）的变体，其中使用MA和GD之间的实际测量距离代替使用观测半径或制造商半径。