A derivative UKF for tightly coupled INS/GPS integrated navigation

The tightly coupled INS/GPS integration introduces nonlinearity to the measurement equation of the Kalman filter due to the use of raw GPS pseudorange measurements. The extended Kalman filter (EKF) is a typical method to address the nonlinearity by linearizing the pseudorange measurements. However, the linearization may cause large modeling error or even degraded navigation solution. To solve this problem, this paper constructs a nonlinear measurement equation by including the second-order term in the Taylor series of the pseudorange measurements. Nevertheless, when using the unscented Kalman filter (UKF) to the INS/GPS integration for navigation estimation, it causes a great amount of redundant computation in the prediction process due to the linear feature of system state equation, especially for the case with system state vector in much higher dimension than measurement vector. To overcome this drawback in computational burden, this paper further develops a derivative UKF based on the constructed nonlinear measurement equation. The derivative UKF adopts the concise form of the original Kalman filter (KF) to the prediction process and employs the unscented transformation technique to the update process. Theoretical analysis and simulation results demonstrate that the derivative UKF can achieve higher accuracy with a much smaller computational cost in comparison with the traditional UKF.     

航位推算法在导航定位中的仿真研究

航位推算(DR)法最初用于船舶的航行定位中,所使用的加速度计、磁罗盘、陀螺仪成本高,尺寸大.而随着微机电系统技术的发展,加速度计、数字罗盘、陀螺仪尺寸、重量、成本都大大降低,使得其可以在行人导航中得以应用.针对DR算法的原理,利用GPS/INS紧密组合导航系统INS 1200进行导航实验,采集实时数据,利用DR算法以及坐标转换算法对实验数据进行处理,通过MATLAB软件模拟了经过坐标变换后的定位图.仿真结果表明,DR算法在短时间内有较高的导航精度,对短时间导航有较大意义.     

基于GPS和INS的测速方法比较分析

目前常用的测速方法包括测速仪、GPS多普勒观测值测速、INS测速、GPS/INS测速等。文章分析了GPS多普勒测速,INS测速以及GPS/INS测速的基本原理。最后,通过对实测的车载实验数据解算对以上这三种方法进行了详细的比较分析,得出了一些比较有意义的结论。     

A double-filter-structure based COMPASS/INS deep integrated navigation system implementation and tracking performance evaluation

Beidou or COMPASS is a Chinese GNSS(global navigation satellite system).Like the GPS receiver,the COMPASS receiver also faces the challenge of choosing an optimal bandwidth to satisfy both anti-jamming capability and dynamics adaptation simultaneously.GPS/INS(inertial navigation system)deep integrated navigation system has solved this problem by fusing GPS baseband signal and INS information in a deeply coupled mode.In this study,a COMPASS B3 frequency is considered and a traditional federated GPS/INS deep integration model is used to derive a single-filter-structure based COMPASS/INS deep integration model.Besides,a double-filter-structure based COMPASS/INS deep integration model is proposed.The simulation results show a better carrier tracking performance,especially a better dynamics adaptation.The impact of IMU errors and vehicle’s dynamics on carrier tracking performance of the double-filter-structure based COMPASS/INS deep integrated navigation system are evaluated in simulated and field environments.Simulation and field test results are in accordance with the theory analysis.     

总体最小二乘法在惯导原位标定中的应用

惯导系统原位标定是提高恒战状态下惯导性能的重要手段.在原位标定输入输出观测数据均含有噪声的情况下,应用传统的最小二乘法进行参数辨识将会得到有偏的结果.因此,为了提高惯导误差参数的标定精度,研究了总体最小二乘法在惯导原位标定数据处理中的应用.首先给出一种16位置标定方案,推导了考虑框架轴、陀螺和加速度计安装误差的惯导系统...     

A Combination Field Desorpt/Fast Atom Bombardment Source for the Ms-50 Mass Spectrometer

ABSTRACT

Conversion of the combination EI/FD source supplied by Kratos for the MS-50 mass spectrometer to a combination FD/FAB source is described. Sensitivities in the combination source are equivalent to those of the stand alone FAB source supplied by Kratos and the EI/FD source. Some compounds could be analyzed by FAB only, others by FD only and a third group were susceptible to both techniques. The advantage of the combination source is that both techniques may be used without having to change ion sources or perform extensive instrumental manipulations.     

基于SAR辅助的INS/Doppler组合导航系统研究

INS/Doppler组合导航系统具有输出水平速度误差和平台角误差较小的优点,但经纬度误差仍随时间增大,故不能作为独立的精确导航定位系统;由于合成孔径雷达(SAR)能够提供高精度的经纬度和航向信息,文中对基于SAR辅助的INS/Doppler组合导航系统进行了研究。仿真结果表明,该系统导航定位精度高、自主性强,比较适用于对导航精度要求较高的大型飞机。     

地磁辅助惯性导航匹配算法研究

对地磁辅助惯性导航技术的基本原理进行了分析，鉴于采样卡尔曼滤波算法在重力辅助导航中的成功应用，将其用于地磁图形匹配。滤波通过设计少量的σ点，并计算这些σ点的经由非线性函教的传播，从而获得滤波值基于非线性状态方程的更新，较广义卡尔曼滤波具有计算精度高、便于计算的特点。     

INS/GNSS组合导航系统校准方法

惯性导航系统(INS)和全球导航卫星系统(GNSS)组合的导航系统应用越来越广泛,它的校准问题亟待解决。本文简要介绍了目前广泛使用的各种导航系统,论述了INS/GNSS组合导航系统的工作原理及组合算法;详细分析了INS/GNSS组合导航系统各种测试及校准方法,比较了各种校准方法的优缺点;提出了INS/GNSS组合导航系统校准装置应具备的条件:可产生标准的空间位置和速度、可产生标准的姿态角度变化、可有效地接收GNSS卫星信号、统一的时间基准与同步信号。     

弹道导弹INS/GNSS/CNS组合导航系统研究

提出了弹道导弹惯性/卫星/天文组合导航系统的方案与组合结构,分析并建立了组合导航系统的误差模型,采用了联邦滤波器进行组合导航系统导航状态的最优估计,并进行了组合导航系统的仿真计算.仿真结果表明采用卫星导航定位系统和天文导航系统对弹道的惯性导航系统进行辅助将大幅度提高弹道导弹的导航精度,具有重要的实际意义.