基于北斗Ka星间链路的地面用户导航方法

针对导航系统L频段信号易受到有意或无意的干扰和欺骗，而导致地面区域性导航服务性能下降甚至失效的问题，提出了一种利用北斗Ka星间链路信号为地面用户提供导航服务的方法。首先，对该方法的可行性进行了研究，并给出了星间链路时分体制下的用户测距模型;然后，提出了基于时钟模型和惯导信息的测距值历元归算方法，并推导了基于北斗星间链路测距值的地面用户实时定位算法;最后，通过数值仿真分析了不同因素对算法性能的影响。仿真结果表明，该方法定位精度可达2.0 m以内，能够在一定程度上弥补L频段导航信号区域性失效带来的缺失。     

One Approach to Ballistic-Navigation Design of an Advanced Space Navigation System

Initial preconditions for solving the problem of ballistic-navigation design of a future-technology space navigation system (SNS) are presented. A technical approach to the SNS design is proposed, whose basis is theoretical results in the field of space navigation applied to the orbital satellite groups, generating the global radio navigation field (RNF) with optimum navigation properties. The mathematical apparatus adequate to the proposed technical approach is introduced to analyze the structure of the orbital group and radio navigation field.     

Integrated solution to the problem of estimation and identification of a state vector of the gimballess navigation system of a reentry spacecraft

An approach to the synthesis of autonomous navigation support is considered for a spacecraft executing an arbitrary spatial maneuver under conditions of internal and external disturbances. The proposed approach ensures the solution to the problem of a joint estimation of the state vector of a navigation system and the identification of the parameters of sensitive elements. A complex observer ensuring the autonomous estimation of the parameters of angular and linear motions is used to improve the accuracy of the estimation of the parameters of angular and linear motions.     

Validation on flight data of a closed-loop approach for GPS-based relative navigation of LEO satellites

This paper describes a carrier-phase differential GPS approach for real-time relative navigation of LEO satellites flying in formation with large separations. These applications are characterized indeed by a highly varying number of GPS satellites in common view and large ionospheric differential errors, which significantly impact relative navigation performance and robustness. To achieve high relative positioning accuracy a navigation algorithm is proposed which processes double-difference code and carrier measurements on two frequencies, to fully exploit the integer nature of the related ambiguities. Specifically, a closed-loop scheme is proposed in which fixed estimates of the baseline and integer ambiguities produced by means of a partial integer fixing step are fed back to an Extended Kalman Filter for improving the float estimate at successive time instants. The approach also benefits from the inclusion in the filter state of the differential ionospheric delay in terms of the Vertical Total Electron Content of each satellite. The navigation algorithm performance is tested on actual flight data from GRACE mission. Results demonstrate the effectiveness of the proposed approach in managing integer unknowns in conjunction with Extended Kalman Filtering, and that centimeter-level accuracy can be achieved in real-time also with large separations.     

基于联邦UKF算法的月球探测器自主组合导航

研究了月球探测器在地一月转移轨道阶段的自主导航方法，提出了利用地月位置信息和星光角距测量信息实现探测器自主组合导航的方案。针对导航系统的状态方程非线性的特点，将Unscented卡尔曼滤波算法和信息融合技术相结合，设计了新的联邦滤波器并应用于自主导航系统中。对这种导航方案进行了数值仿真，和传统的联邦滤波算法进行了比较。仿真结果表明，所提出的组合导航方法和联邦滤波算法的导航位置估计精度约为1km，速度估计精度约为0．01m／s，并且具有良好的鲁棒性和容错性能。     

An innovative high accuracy autonomous navigation method for the Mars rovers

Autonomous navigation is an important function for a Mars rover to fulfill missions successfully. It is a critical technique to overcome the limitations of ground tracking and control traditionally used. This paper proposes an innovative method based on SINS (Strapdown Inertial Navigation System) with the aid of star sensors to accurately determine the rover?s position and attitude. This method consists of two parts: the initial alignment and navigation. The alignment consists of a coarse position and attitude initial alignment approach and fine initial alignment approach. The coarse one is used to determine approximate position and attitude for the rover. This is followed by fine alignment to tune the approximate solution to accurate one. Upon the completion of initial alignment, the system can be used to provide real-time navigation solutions for the rover. An autonomous navigation algorithm is proposed to estimate and compensate the accumulated errors of SINS in real time. High accuracy attitude information from star sensor is used to correct errors in SINS. Simulation results demonstrate that the proposed methods can achieve a high precision autonomous navigation for Mars rovers.     

Geometric reasoning under uncertainty for map-based localization

Map-based navigation in outdoor terrain lacking man-made structures or other highly distinctive landmarks can produce severe localization problems. This paper presents an approach to navigation which implements high level geometric reasoning and matching strategies based on those used by skilled human navigators. This approach, which is demonstrated on a real example involving imagery of mountainous terrain obtained with a video camera and USGS map data, is designed to avoid many of the pitfalls occurring when an attempt is made to navigate by modeling the environment mathematically. It exploits feature attributes which cannot be easily expressed quantitatively but are central to the successful human navigation process.     

深空着陆器随机优化制导律设计

针对导航估计误差对制导精度的不利影响,提出了一种随机优化制导设计方法。该方法将导航估计性能作为优化项引入制导设计过程中,通过对观测轨迹的优化设计,使视觉导航估计精度得到提高,进而改善了制导性能;同时,引入单步超前优化方法减少迭代运算量。将其应用于深空探测着陆任务,仿真结果表明与传统估计最优制导方法相比,该随机优化制导律有效降低了估计误差给制导系统带来的不利影响,使着陆器导航与制导系统整体性能得到改善提高。     

脱靶量估算和广义比例导引

本文提出一种适于真比例导引系统估计脱靶量的方法，依据这种方法，只要知道制导－控制时间延迟、拦截器的目标的相对运动速度等，就可以估计出脱靶量的大小。本文还就减小脱靶量而有采用广义比例导引的前景进行了探讨。     

微小卫星磁测自主导航方法

本文提出了使用磁测方法实现近地微小卫星自主导航的方法，利用实时地磁场测量数据与根据ＩＧＲＦ计算出的地磁声数据之差作为新息量，使用推广Ｋａｌｍａｎ滤波算法确定卫星的位置和速度。给出了三种导航滤波算法。并使用模拟数据和ＭＡＧＳＴＡ卫星实测数据进行了仿真研究，证明了方法的有效性和实用性。     

Navigation in outdoor environments as an embodied,social, cultural,and situated experience: An empirical study of orienteering

This study investigated novices' “lived experiences” of navigation within the sport of orienteering from an enactive and phenomenological approach. The objective was to qualitatively characterize elements of task-related situations that were meaningful for orienteers. The results showed that the participants continuously made judgments about the reliability of their estimations about whether they were on “the right route” on the course. When the participants judged that they were only approximately on the right route or were unable to locate themselves, elements of the situation other than map and terrain features became meaningful for them. These results demonstrate that, for novice orienteers, navigation activity must extend beyond navigation as a logical, computational way-finding problem to include embodied, social, cultural and situated dimensions.     

基于四元数法的舰载无人机回收系统测高技术研究

文章针对舰载无人机在着舰回收过程中,由于海浪颠簸对引导系统高度测量严重干扰的问题,利用四元数导航算法提出了一种新型的舰载无人机回收系统测高方法。首先采用捷联惯导测高系统设计方案,同时利用微机械的惯性测量组件,提高系统的可靠性和集成度;然后,利用四元数导航算法求取各个姿态方位参数,再用旋转矢量法补偿不可交换性误差,推导出舰船甲板的升沉高度实际值,为克服传统纯惯导测量算法的不稳定性,提出一种具有三阶阻尼特性的互补滤波器算法,并在测量系统输入端加入巴特沃斯滤波器去除杂波干扰,得到需要测量的高度变化值。最后,通过对比传统纯惯性方法下测高系统输出值、加入真实气压表互补滤波后测高系统输出值和加入零均值阻尼信号互补滤波测高系统输出值,三种不同情况下的仿真结果,验证了所提方案的有效性。     

一种新的动基座快速传递对准方案及其仿真研究

针对捷联惯导系统的动基座初始对准问题,提出了一种新的动基座快速传递对准方案。该方案采用速度 姿态变化量匹配,直接对主、子惯导导航坐标系之间的失准角进行估计,可以使航向失准角快速收敛。通过仿真,研究了注入噪声和测量噪声水平、机动运动强度和幅度、复合机动运动、载机运动方向等六个因素对对准性能的影响。结果表明:其对准性能取决于水平失准角的估计精度和速度;失准角的估计精度和速度与注入噪声水平和测量噪声水平、机动运动的强度和幅度有关;复合机动运动对对准性能有正反两方面的影响。     

基于神经网络的SINS/GPS/TAN 容错组合导航系统设计

在联邦滤波器结构的基础上 ,设计了一种基于神经网络的天文惯性导航系统 /全球卫星定位系统 /战术导航系统 (SINS/GPS/TAN)容错组合导航系统。该系统首先在各子滤波器中用神经网络滤波 (NNF)代替传统的卡尔曼滤波 ,然后用模糊神经网络 (FNN)对各子系统进行故障检测 ,最后由神经元进行全局融合。通过仿真 ,验证了该方法的有效性     

双天线GPS/MEMS-INS深组合导航方法研究

针对低成本惯性/卫星组合导航系统在复杂环境中易受环境干扰、航向精度较差等问题,对双天线GPS/MEMS-INS深组合导航方法开展研究。考虑不同信号强度下的跟踪特性,基于矢量延迟锁定环(VDLL)、二阶锁相环(PLL)、速度辅助的一阶锁相环,设计了分别适应强信号、弱信号、失锁状态的跟踪环路结构。同时提出一种实用的信号强度判别方法,防止失准通道参与导航滤波器计算,提高导航精度。为保证航向精度,使用双天线接收卫星信号,将双天线载波相位差加入到导航滤波器的量测量中。采用视线矢量水平投影变换,构造了隔离俯仰信息的相位差量测方程,在不对俯仰角造成干扰的条件下修正航向角误差。车载导航试验表明,所设计的导航系统可以在城市环境中提供连续、高精度的导航输出。     

基于信息理论的INS／Vision相对导航系统可观测度分析

基于导弹编队协同作战的应用背景,提出了一种基于INS／Vision的相对导航方法。推导了领弹与从弹间的相对惯导方程,给出了使用视觉导航设备测量领弹与从弹间相对视线矢量的原理。用扩展卡尔曼滤波融合相对惯导信息和相对视线矢量信息,估计相对位置、相对速度和相对姿态。用信息理论分析相对导航系统可观测度,给出随机变量的熵和共有信息的定义,将共有信息作为系统可观测度的衡量标准,分析了INS／Vision相对导航系统状态的可观测度,由此确定位置估计精度最高时领弹与从弹间的相对位置关系。仿真研究验证了相对导航方法的有效性和可观测度分析结果的正确性。     

GPS在航天器编队飞行任务中的基础性作用

GPS正在改变航天器的测控格局 ,拓宽卫星和星座控制技术 ,从而构成空间编队飞行定时、测量和控制的技术基础。国内外已开发出对航天器编队飞行任务进行精确定位和导航的GPS方案。GPS将充当一大类多航天器编队飞行任务的导航系统。在当前开发的空间编队飞行技术中 ,编队航天器的测量和控制、星间链路通信、任务综合与验证、编队飞行试验台、分散式控制、高轨道航天器的相对导航等 ,无一不与GPS息息相关     

多星编队相对轨道的自主确定

编队飞行的相对轨道确定具有重要意义。针对编队应用中多颗环绕星相对中心星的自主定轨问题进行了研究，提出引入环绕星间相对测量信息的分布式滤波方案。设计了二级滤波器，利用环绕星间测量信息提高一级滤波得到的环绕星相对轨道的确定精度。仿真结果验证了这种导航方案的有效性。     

相对轨道自主确定方法的改进

编队飞行卫星相对轨道的确定具有重要意义。本文提出一种完全自主的定轨方案,在利用星间测量信息实现编队飞行卫星自主定轨的基础上,引入太阳敏感器测量信息,利用扩展卡尔曼滤波算法提高环绕星相对轨道确定精度。仿真结果验证了这种导航方案和算法的有效性。     

采用强制降噪和多尺度融合的地磁导航方法

针对地磁数据测量易受各种噪声和干扰影响,导致地磁匹配导航精度、概率和可靠性降低的问题,提出了一种采用小波强制降噪和多尺度融合的地磁匹配导航方法。该方法利用地磁数据高频部分易受噪声干扰影响而低频部分稳定性好、各尺度下的匹配结果具有相对独立性的特点,将含噪地磁基准图和实时图进行多尺度分解,在所选的多个尺度下经强制降噪后分别进行匹配,并融合各尺度下的匹配结果表决产生最终的导航结果。地磁匹配导航仿真实验结果表明该方法可有效提高导航的精度、概率和可靠性。