高精度X射线光子到达时间转换模型对脉冲星导航的精度至关重要,针对目前完整模型复杂而简化模型精度有限的问题,本文提出了一种精度不低于已有简化模型的快速简化模型.通过对现有完整模型的推导,从理论上分析了各延迟项对模型精度的影响,指出罗曼延迟仍是影响简化模型精度的关键.通过改变罗曼延迟的表达式及其二阶展开方式并考虑物理量的易获取度,得到一种快速简化模型.利用完整模型及所提简化模型对中子星内部组成探测器(Neutron star Interior Composition Explorer,NICER)和慧眼硬X射线调制望远镜(Hard X-ray Modulation Tele-scope,HXMT)的实测光子数据进行时间转换,分析了所提模型的精度和计算效率;利用数值仿真分析了轨道高度、脉冲星角位置测量误差对简化模型精度的影响,讨论了不同高度地球轨道应用中该简化模型的精度及计算效率.结果表明本文所提简化模型相比Sheikh简化模型和fei模型计算效率分别提高50%和10%,且未造成精度降低.
A Fast Simplified Model for X-ray Pulsar Photon Arrival Time Conversion
A high-precision X-ray photon arrival time conversion model is crucial to the accuracy of X-ray Pulsar-based Navigation.Aiming at the current problem that the complete model is complex and the simplified model has limited accuracy,a fast simplified model with accuracy no less than the existing simplified model is proposed in this paper.Through the derivation of the existing complete model,the influence of each delay item on the accuracy of the model is the-oretically analyzed,and it is pointed out that the Roemer delay is still the key to the accuracy of the simplified model.A fast simplified model was obtained by changing the expression of the Roemer delay and its second-order expansion,and consid-ering the ease of access to physical quantities in practical application.The accuracy and computational efficiency of the pro-posed model are analyzed by using the complete model and the proposed simplified model to time-transform the measured photon data of NICER(Neutron star Interior Composition Explorer)and HXMT(Hard X-ray Modulation Telescope)satel-lites.Furthermore,the influence of orbital altitude and pulsar angular position measurement errors on the accuracy of the simplified model is analyzed by numerical simulation,and the accuracy and computational efficiency of the simplified mod-el in the application of Earth orbit at different altitudes are discussed.The results show that the computational efficiency of the simplified model proposed in this paper is improved 50%than that of the Sheikh's simplified model and 10%than the fei's model,without causing a decrease in accuracy.
X-ray pulsartime conversion modelphoton arrival timehigh-precision simplified model
万方数据
维普
