Iterative Estimation of Location and Trajectory of Radioactive Sources With a Networked System of Detectors
Iterative Estimation of Location and Trajectory of Radioactive Sources With a Networked System of Detectors
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DOI：
10.1109/tns.2013.2247060
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发表时间：
2013-04-01
影响因子：
1.8
通讯作者：
Deb, Budhaditya
中科院分区：
文献类型：
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作者：
Deb, Budhaditya
我们考虑使用辐射探测器系统估计多个放射源的参数（位置和强度）的问题。问题制定为最大似然估计（MLE）需要优化的高维目标函数，并提出了重大的计算挑战。我们提出了Fisher的评分迭代方法（牛顿迭代法的一个特殊情况）寻找极大似然估计。虽然在计算上是可扩展的，但这种方法的固有问题是特别是当存在多个源时找到良好的初始估计。我们提出了一种基于期望最大化（EM）的方法，该方法可以找到源强度在空间中的近似分布。该分布中的峰被用作参数的初始估计以引导迭代MLE过程。接下来，我们考虑的问题，估计的运动和机动源的轨迹。由于不能假设先验运动模型，因此轨迹被近似为一组点，这再次提出了高维估计问题。轨迹估计被视为一个约束加权最小二乘问题，使用内点法（IPM）迭代求解。仿真结果表明，我们所提出的方法的行为和性能。
We consider the problem of estimating the parameters (location and intensity) of multiple radioactive sources using a system of radiation detectors. The problem formulated as maximum likelihood estimation (MLE) requires the optimization of a high-dimensional objective function and presents significant computational challenges. We propose Fisher's scoring iterations approach (a special case of Newton's iterative method) for finding the MLE. While being computationally scalable, an inherent problem with this approach is finding good initial estimates specifically when multiple sources are present. We propose an expectation maximization (EM) based approach which finds the approximate distribution of the source intensity in space. Peaks in this distribution are used as initial estimates of the parameters to bootstrap the iterative MLE procedure. Next, we consider the problem of estimating the trajectory of a moving and maneuvering source. Since a priori motion model cannot be assumed, the trajectory is approximated as a set of points which again presents a high dimensional estimation problem. The trajectory estimation is posed as a constrained weighted least squares problem which is iteratively solved using the Interior Point Method (IPM). Simulation results are presented which illustrate the behavior and performance of our proposed approaches.