卫星定位系统与飞行力学

概述了卫星定位系统的发展和应用，重点论述了它与飞行力学的关系，在ＧＰＳ卫星星座布置，地面站测控和用户应用中，飞行力学及其相关学科作为应用基础起到了重要的作用，成为卫星定位这门新兴交叉学科的一部分，最后提出了作为ＧＰＳ高级应用专题的飞行力学若干研究课题。     

一种基于NOMA的Q学习卫星通信随机接入方法

基于非正交多址接入(NOMA)的Q学习(Q-Learning)随机接入方法(NORA-QL)是实现物联网中海量设备泛在接入的一项有效技术.为了解决NORA-QL方法仍存在的传输能效和过载容量较低的问题,提出了一种适合卫星通信网络的改进方法(I-NORA-QL).针对传输功耗高的问题,I-NORA-QL利用卫星广播的全局...     

The contribution of local gravimetric geoid models to the calibration of satellite altimetry data and an outlook of the latest GOCE GGM performance in Gavdos

The use of geoid heights has been one of the available methodologies utilized for the independent calibration/validation of altimeters on-board satellites. This methodology has been employed for long in the Gavdos dedicated cal/val facility (Crete, Greece), where calibration results for the Jason satellites have been estimated, both for ascending and descending passes. The present work gives a detailed overview of the methodology followed in order to estimate a high-resolution and accuracy gravimetric geoid model for the wider Gavdos area, in support of the on-going calibration work. To estimate the geoid model, the well-known remove-compute-restore method is used while residual geoid heights are estimated through least-squares collocation so that associated errors are determined as well. It is found that the estimated formal geoid errors from LSC along passes 018 and 109 of Jason satellites, used for the bias estimation, range between ±0.8–1.6 cm. The so-derived geoid heights are employed in the determination of the Jason-2 altimeter bias for all available cycles (cycles 1-114, spanning the period from July 2008 to August 2011) together with the RioMed DOT model. From the results acquired the Jason-2 bias has been estimated to be +196.1 ± 3.2 mm for pass 109 and +161.9 ± 5.1 mm for pass 018. Within the same frame, the GOCE/GRACE-based geopotential model GOCO02s has been used to estimate the mean dynamic ocean topography and the steady-state circulation in the area around Gavdos. The so-derived DOT model was used to estimate the Jason-2 bias in an effort to evaluate the performance of satellite-only geoid models and investigate whether their spatial resolution and accuracy provides some improvement w.r.t. traditional local gravimetric geoids. From the results acquired with geoid heights from GOCO02s, the estimated Jason-2 bias deviates significantly from that of the local gravimetric model, which can be attributed to a possible mean offset and the low resolution of GOCE-based GGMs. On the other hand, when the newly estimated GOCE-based DOT was employed with geoid heights from the local gravimetric geoid model, the Jason-2 bias has been estimated to be +185.1 ± 3.2 mm for pass 109 and +130.2 ± 5.1 mm for pass 018.     

高校职工保险管理系统的设计

本文描述了职工保险管理系统的组成及应用，介绍了系统的功能特点和实现方法，该系统对学校，机关等中小型事业单位的职工保险管理有一定的实用价值。     

Monitoring the South Atlantic Anomaly using ATSR instrument series

The South Atlantic Anomaly (SAA) has been monitored for 19 years using the Along Track Scanning Radiometer (ATSR) series of instruments onboard the ERS-1, ERS-2 and ENVISAT ESA satellites. The time evolution of the night-time particle induced noise in the short wavelength infrared (SWIR, 1.6 μm) and visible (VIS, 0.55 μm) channels of the ATSR instrument series have been analysed. The monthly location and extension of the SAA are inferred by fitting a two-dimensional, elliptical Gaussian function to the coordinates of the night-time hot spots detected over the SAA region. The location of the centre of the SAA is found to drift westwards with an average drift rate of about 0.24 deg/year and northward with an average drift rate of about 0.12 deg/year. Irregularities are found where the drift speed is inverted and the SAA moves eastward and southward. Results indicate that, as expected, the retrieved values of SAA’s strength and extension are anti-correlated with the solar activity expressed by the solar flux at 10.7 cm (F10.7). Finally, the peak-to-peak amplitude of the seasonal variation of the SAA strength, estimated from monthly VIS data, is found to be 30% of the average value with the annual to semiannual amplitude ratio of 1.38.     

地球静止轨道卫星撞击解体的数值模拟

分析了地球静止轨道（GE0）环内的物体现状,引入美国家航空航天局（NASA）的标准解体模型,给出了卫星撞击解体算法,编写了数值仿真软件,仿真研究了GEO卫星撞击解体形成碎片的特征及其轨道分布。结果表明：撞击会产生大量碎片,对空间环境造成长期的严重危害。研究结果对分析卫星撞击解体特性、保护空间环境有一定的参考价值。     

二次多项式拟合外方位元素卫星三线阵C CD影像平差

文章针对一景大小的卫星三线阵CCD影像,采用二次多项式拟合外方位元素模型,与国外的定向片法模型进行平差算法对比.对一景大小的模拟数据进行了试验,结果表明基于二次多项式拟合外方位元素模型的平差方法有效的提高了影像的平面精度与高程精度,与定向片法模型相比,该算法简单,结果同样满足1∶5万摄影测量的要求.     

多指标LMI鲁棒故障检测滤波器在卫星姿态控制系统中的应用

卫星在轨运行中,需要对其故障进行及时的检测,模型的不确定性使得如何在轨卫星的故障检测产生了很大的干扰。以往的方法是将故障、输入和干扰统一作为广义输入,通过H∞范数增益最小使得系统残差最大程度地接近于故障,然而这不能反映故障、输入和干扰三者的重要关系。为此需要研究三者到残差增益的多指标下,滤波器的参数设计方法。以推导从三者到残差的传递函数表达式为主要方法,以线性矩阵不等式为工具,把指标化为可求解模型,得到多指标下的故障检测滤波器设计方法。设计的滤波器应用于采用喷气执行机构的在轨卫星模型里,给出了滤波器的设计结果。从仿真的结果看,虽然三个增益无法满足同时远远小于1的条件,但通过自适应的阈值,可实现对在轨喷气执行器卫星的鲁棒故障检测。     

基于PXI总线的实时综合测试系统研究

为提高现有卫星测试系统的效率,对基于PXI总线的实时综合测试系统进行了研究。给出了测试系统的中央控制台、实时测试仿真单元和控制输出单元和辅助测试装置主要硬件构成,以及任务管理、实时测试仿真单元、控制输出单元和显示终端等软件组成。介绍了系统的工作原理,以及实时测控、多平台间实时数据共享交互等关键技术。结果表明,该系统从实时测试仿真单元信号采集至仿真运算结束的时间约1~10 ms。     

基于Kalman滤波器的卫星钟实时异常监测算法

基于卫星钟钟差的Kalman滤波器模型,提出了一种卫星钟实时异常监测算法,对算法原理进行了讨论,并利用IGS精密钟差数据,对算法进行了性能验证。结果表明：该算法对卫星钟的异常情况（包括单点相位跳变与连续相位跳变）可以进行有效监测,同时还可以完成异常数据的剔除与替换,并且具有较小的替换误差。该算法具有显著的实时性,可以应用于星载原子钟的实时异常监测中。