论文标题
使用两个非同步定位系统的伪造测量的封闭形式定位方法
A Closed-form Localization Method Utilizing Pseudorange Measurements from Two Non-synchronized Positioning Systems
论文作者
论文摘要
在基于到达的时间（TOA）或伪基的定位系统中，可以通过在已知位置观察多个锚节点（AN）来获得用户位置。利用多个定位系统，例如结合全球定位系统（GPS）和Beidou导航卫星系统（BDS），可以提高定位精度。但是，来自两个系统的ANS通常被同步到两个不同的时钟源。与单系统本地化不同，需要处理额外的用户到系统时钟偏移量。现有的双重系统方法具有较高的计算复杂性或亚最佳定位精度。在本文中，我们提出了一种新的封闭形式的双系统定位（CDL）方法，该方法的复杂性和最佳定位精度。我们首先将非线性问题转换为线性问题，通过平方距离方程并采用中间变量。然后，使用加权最小二乘（WLS）方法来优化定位精度。我们证明，新方法的定位误差在远场条件下以较小的测量噪声达到CRAMER-RAO下限（CRLB）。进行了2D和3D定位场景的模拟。结果表明，与具有高复杂性并且需要良好初始化的迭代方法相比，新的CDL方法不需要初始化，并且具有较低的计算复杂性，并且定位精度可比。数值结果验证了定位准确性的理论分析，并表明新的CDL方法比最新的封闭形式方法具有出色的性能。使用实际GPS和BDS数据的实验验证了新CDL方法的适用性及其在现实世界中的性能的优势。
In a time-of-arrival (TOA) or pseudorange based positioning system, user location is obtained by observing multiple anchor nodes (AN) at known positions. Utilizing more than one positioning systems, e.g., combining Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS), brings better positioning accuracy. However, ANs from two systems are usually synchronized to two different clock sources. Different from single-system localization, an extra user-to-system clock offset needs to be handled. Existing dual-system methods either have high computational complexity or sub-optimal positioning accuracy. In this paper, we propose a new closed-form dual-system localization (CDL) approach that has low complexity and optimal localization accuracy. We first convert the nonlinear problem into a linear one by squaring the distance equations and employing intermediate variables. Then, a weighted least squares (WLS) method is used to optimize the positioning accuracy. We prove that the positioning error of the new method reaches Cramer-Rao Lower Bound (CRLB) in far field conditions with small measurement noise. Simulations on 2D and 3D positioning scenes are conducted. Results show that, compared with the iterative approach, which has high complexity and requires a good initialization, the new CDL method does not require initialization and has lower computational complexity with comparable positioning accuracy. Numerical results verify the theoretical analysis on positioning accuracy, and show that the new CDL method has superior performance over the state-of-the-art closed-form method. Experiments using real GPS and BDS data verify the applicability of the new CDL method and the superiority of its performance in the real world.
