Pulsar phase and doppler frequency estimation for XNAV using on-orbit epoch folding
Pulsar phase and doppler frequency estimation for XNAV using on-orbit epoch folding
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DOI：
10.1109/taes.2016.7812871
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发表时间：
2016-10
影响因子：
4.4
通讯作者：
Yidi Wang;Wei Zhang-
中科院分区：
文献类型：
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作者：
Yidi Wang;Wei Zhang-
介绍了一种用于X射线脉冲星导航（XNAV）的脉冲星相位和多普勒频率估计方法。在考虑飞行器轨道运动的情况下，推导出了一种修正的相位传播模型。针对深空探测器使命，推导了线性化的脉冲星相位模型，将接收相位分为预测部分和估计部分。提供了一个称为在轨历元折叠的框架。该框架包括消除飞行器轨道运动效应、寻找转换光子到达时间（TOA）周期和估计初始相位。消除飞行器轨道运动的影响，可以将原始的时变频率的光子到达时间转换为恒定频率的光子到达时间。通过将经验分布描述为直方图并通过最大化直方图的对数似然函数来导出用于搜索该时段的成本函数。现有算法可以很好地解决初始相位问题。仿真结果表明，该方法对深空各种飞行器都是可行的。
This paper introduces a pulsar phase and Doppler frequency estimation method for X-ray pulsar-based navigation (XNAV) using on-orbit epoch folding. A modified phase propagation model is derived as a term of position of vehicle, taking the orbital motion of the vehicle into account. For a deep space explorer mission, a linearized pulsar phase model is derived, dividing the received phase into a predicted part and an estimated part. A framework called on-orbit epoch folding is provided. The framework consists of removal of vehicle orbital motion effect, search for the period of converted photon time of arrivals (TOAs), and estimation of the initial phase. The removal of vehicle orbital motion effect can convert the original photon TOAs with a time-varying frequency into a photon TOA with a constant frequency. A cost function for the search for the period is derived by describing the empirical profile as a histogram and by maximizing the log-likelihood function of histogram. And the initial phase problem can be well solved by existing algorithms. Simulations have shown that the proposed method is feasible to various vehicles in deep space.