Autonomous navigation during the final ascent of a spacecraft into the geostationary orbit. Autonomous integrated navigation system concept

Journal of Computer and Systems Sciences International - This paper is the first in a series of works devoted to the problems of a spacecraft in the geostationary orbit autonomous operation. The...     

航天器控制系统的自主诊断重构技术

自主诊断重构是确保航天器控制系统安全可靠自主运行的关键技术之一.本文针对航天器资源严重受限的客观情况,改变传统一味追求华丽算法与豪华配置的设计理念,从航天器的自身特性出发,深入挖掘诊断重构问题的本质,提出基于可诊断性与可重构性评价设计的研究思路.文章首先介绍了航天器自主诊断重构技术的发展现状,分析了当前技术的不足之处并探究了其深层原因;然后,提出了通过可诊断性与可重构性评价设计从根本上提高系统自主诊断重构能力的全新思路,梳理了其研究内容与研究概况;最后,对航天器控制系统自主诊断重构技术的发展趋势进行了展望.     

Autonomous navigation system using Event Driven-Fuzzy Cognitive Maps

This study developed an autonomous navigation system using Fuzzy Cognitive Maps (FCM). Fuzzy Cognitive Map is a tool that can model qualitative knowledge in a structured way through concepts and causal relationships. Its mathematical representation is based on graph theory. A new variant of FCM, named Event Driven-Fuzzy Cognitive Maps (ED-FCM), is proposed to model decision tasks and/or make inferences in autonomous navigation. The FCM??s arcs are updated from the occurrence of special events as dynamic obstacle detection. As a result, the developed model is able to represent the robot??s dynamic behavior in presence of environment changes. This model skill is achieved by adapting the FCM relationships among concepts. A reinforcement learning algorithm is also used to finely adjust the robot behavior. Some simulation results are discussed highlighting the ability of the autonomous robot to navigate among obstacles (navigation at unknown environment). A fuzzy based navigation system is used as a reference to evaluate the proposed autonomous navigation system performance.     

Autonomous navigation during the final ascent of a spacecraft into the geostationary orbit. II. Simulation of operation of an integrated autonomous SC navigation and control system

This study continues the series of papers devoted to the approach to solving the problem of autonomous navigation of a spacecraft (SC) in a geostationary orbit at all stages of its lifecycle: final ascent, transfer to the operating longitude, remaining at the operating longitude, removal from the orbit, and burial. In [1], we formulated the concept of autonomous navigation of a spacecraft at the stage of its final ascent to a geostationary orbit. This stage is most complicated from the technical point of view, taking into account the nonlinearity of the applied mathematical models, the influence of uncontrollable factors of various physical nature, and the necessity of the application of promising hardware (electric low-thrust engine, onboard receiver of signals from global navigation satellite systems, intersatellite communication channels, etc.). Taking this into account, the only constructive method for proving the viability and efficiency (taking into account the requirements formulated by the customer who placed the order) of the developed concept of the autonomous navigation at the final ascent stage in the mathematical simulation of this process. The subject of this study is to demonstrate the capabilities of the developed concept of autonomous navigation from the point of view of achieving the required level of reliability and accuracy in solving the navigation problem at the final ascent stage. This demonstration is based on the analysis of the results of imitating the simulation of the process of a spacecraft’s final ascent to a geostationary orbit obtained using the specially developed software complex.     

基于脉冲星脉冲信号的航天器导航系统

脉冲星是具有107—109T强磁场的快速自转中子星,会不断地发出周期性电脉冲信号。通过识别脉冲轮廓可以实现航天器的定位和姿态调整。将采集到的光子到达时刻的TDC数据通过USB传送到上位机进行脉冲轮廓还原得到光子到达时间(TOA)。利用西安光学精密机械研究所的X射线地面模拟系统产生B0531星系进行测试,得到的脉冲轮廓与在NASA下载的B0531星数据的脉冲轮廓相似度达到95.38%。     

无人机多源导航信息自主管理方法研究

完全依赖卫星导航信息融合的方案自主性差、完好性难以保证;而完全利用其它自主导航的方式,精度也难以保证,针对这些问题,提出了基于混合式架构的多源导航信息自主管理方法.利用联合故障检测方法,解决了对卫星干扰的有效检测,使完好性得到保证;设计了基于D–S证据推理的信息优选策略,针对典型无人机任务场景进行了仿真分析,结果表明信息优选策略降低了多故障检测方法同时应用的虚警率,提高了导航精度.     

GPS-correction in the problem of low-orbit spacecraft navigation

Algorithms for the spacecraft navigation with correction by messages of a global positioning satellite system are proposed. This approach to solving the navigation problem allows for the combination of a given average level of accuracy with saving of computation resources.     

非合作航天器自主相对导航研究综述

非合作航天器自主相对导航作为与非合作航天器实现空间交会对接过程中的关键技术,是在轨服务技术的重点发展方向之一,其研究具有重要的理论价值与工程意义.针对在轨服务任务对于自主相对精确导航的需求,本文对发展非合作航天器自主相对导航技术的必要性进行了阐述.首先总结了非合作航天器自主相对导航技术的内涵与研究现状;随后分析梳理了非合作航天器自主相对导航过程涉及到的光学敏感器、位姿测量、导航滤波器以及地面实验等关键技术.最后根据研究现状和关键技术的分析指出了非合作航天器自主相对导航目前存在的主要问题并给出后续发展的建议.     

Strapdown inertial navigation systems for high precision near-Earth navigation and satellite geodesy: Analysis of operation and errors

Specific features of the solution of problems of near-Earth inertial navigation are described for applications in which geodetic-class precision is required, the connection of problems of autonomous inertial navigation and satellite gravimetry, their complementary and contradictory character are considered, navigation support of modern projects of satellite geodesy is analyzed. The architecture of a precise strapdown inertial navigation system is considered, the mathematical model for its operation with account of errors is proposed. Error equations are obtained in a general nonlinear form. The specific features of the constructed model are the account of variations of velocity of the Earth’s self rotation, the nonstationary character of the Earth’s gravitational field, the gravitational influence of the Sun, the Moon, planets, and the account of tidal, tectonic, seasonal motions of the navigation coordinate system whose origin is situated at the point of the surface of the elastic Earth with respect to the Earth’s geocentric coordinate system.     

Autonomous navigation for high altitude satellites

The determination of the orbit of high altitude satellites with an accurate horizontal charge coupled device (CCD) sensor is considered using the extended Kalman filter. The measurement nonlinearity is removed by using a coordinate transform, and the corresponding steady state error is less than the steady state error in the Cartesian coordinate system. The performance of both of the navigational filters is evaluated for a reference geosynchronous orbit as a function of measurement error. The reduction of measurement uncertainty decreased steady state errors in position and velocity.     

Autonomous over-the-horizon navigation using LIDAR data

In this paper we present the approach for autonomous planetary exploration developed at the Canadian Space Agency. The goal of this work is to enable autonomous navigation to remote locations, well beyond the sensing horizon of the rover, with minimal interaction with a human operator. We employ LIDAR range sensors due to their accuracy, long range and robustness in the harsh lighting conditions of space. Irregular Triangular Meshes (ITMs) are used for representing the environment, providing an accurate, yet compact, spatial representation. In this paper a novel path-planning technique through the ITM is introduced, which guides the rover through flat terrain and safely away from obstacles. Experiments performed in CSA’s Mars emulation terrain, validating our approach, are also presented.     

Autonomous mobile robot navigation and learning

Research focused on the development and experimental validation of intelligent control techniques for autonomous mobile robots able to plan and perform a variety of assigned tasks in unstructured environments is presented. In particular, an autonomous mobile robot, HERMIES-IIB intelligence experiment series, is described. It is a self-powered, wheel-driven platform containing an onboard 16-node Ncube hypercube parallel processor interfaced to effectors and sensors through a VME-based system containing a Motorola 68020 processor, a phased sonar array, dual manipulator arms, and multiple cameras. Research on navigation and learning is examined     

Autonomous navigation and obstacle avoidance using navigation laws with time-varying deviation functions

In this paper we introduce a new family of navigation functions for robot navigation and obstacle avoidance. The method can be used for both path finding and real-time path planning. Each navigation function is composed of three parts: a proportionality term, a deviation function and a deviation constant. Deviation functions are time-varying functions satisfying certain conditions. These functions and parameters are updated in real-time to avoid collision with obstacles. Our strategy uses polar kinematics equations to model the navigation problem in terms of the range and direction between the robot and the goal. The obstacles are mapped to polar planes, and represented by the range and the direction from the robot or the final goal in polar coordinates. This representation gives a certain weight to the obstacles based on their relative position from the robot and facilitates the design of the navigation law. There exists an infinite number of navigation functions obtained by changing the proportionality constant, the deviation constant or the deviation function. This offers an infinite number of possibilities for the robot's path. Our navigation strategy is illustrated using an extensive simulation where different navigation parameters are used.     

A variant of visual correction in the problem of spacecraft navigation

Possibility of correction of parameters of spacecraft orbital motion using observations of not more than one ground landmark at short time intervals is considered.     

Autonomous mobile robots navigation using RBF neural compensator

This paper presents an approach to adaptive trajectory tracking of mobile robots which combines a feedback linearization based on a nominal model and a RBF-NN adaptive dynamic compensation. For a robot with uncertain dynamic parameters, two controllers are implemented separately: a kinematics controller and an inverse dynamics controller. The uncertainty in the nominal dynamics model is compensated by a neural adaptive feedback controller. The resulting adaptive controller is efficient and robust in the sense that it succeeds to achieve a good tracking performance with a small computational effort. The analysis of the RBF-NN approximation error on the control errors is included. Finally, the performance of the control system is verified through experiments.     

基于代理的航天器自主运行仿真系统设计与验证系统设计

针对目前航天器自主健康管理功能测试过程中,由于故障模拟手段不足造成测试覆盖率低,测试项目不完备,测试效率低等问题,提出一种基于代理的航天器自主健康故障仿真验证系统设计方案;基于该方案实现的故障仿真系统支持根据通用化航天器自主健康故障检测模型,严格按逻辑和时序,无延迟、持续的向全实物或半实物测试系统自动注入故障状态表征参数,模拟航天器整器或任意分系统、单机、软件的故障状态,模拟弥补了长期以来在实物测试环境下,整器故障模式测试覆盖率低,测试用例复用性差的问题;实践证明,此方法能将测试覆盖率提升至95%以上,并将测试时间缩短至传统方式的1/6,有效提升被测航天器产品可靠性。     

Autonomous robot navigation in outdoor cluttered pedestrian walkways

This paper describes an implementation of a mobile robot system for autonomous navigation in outdoor concurred walkways. The task was to navigate through nonmodified pedestrian paths with people and bicycles passing by. The robot has multiple redundant sensors, which include wheel encoders, an inertial measurement unit, a differential global positioning system, and four laser scanner sensors. All the computation was done on a single laptop computer. A previously constructed map containing waypoints and landmarks for position correction is given to the robot. The robot system's perception, road extraction, and motion planning are detailed. The system was used and tested in a 1‐km autonomous robot navigation challenge held in the City of Tsukuba, Japan, named “Tsukuba Challenge 2007.” The proposed approach proved to be robust for outdoor navigation in cluttered and crowded walkways, first on campus paths and then running the challenge course multiple times between trials and the challenge final. The paper reports experimental results and overall performance of the system. Finally the lessons learned are discussed. The main contribution of this work is the report of a system integration approach for autonomous outdoor navigation and its evaluation. © 2009 Wiley Periodicals, Inc.     

基于天文/GPS的HEO卫星自主导航方法

为了实现大椭圆轨道(HEO)卫星高精度自主导航,提出一种将直接敏感地平天文导航与全球定位系统(GPS)相结合的组合导航方法.首先,分析卫星轨道??2运动模型及其所受空间摄动,建立卫星轨道动力学模型;然后,分析单一使用天文导航和GPS的优缺点,根据HEO卫星对GPS的可见性,提出在远地点只采用天文导航,而在近地点采用以天文导航为主、适时引入GPS信号进行位速测量辅助修正的方法.通过计算机仿真和结果分析表明了所提出的设计方法导航精度比单一天文导航提高72.4%～85.6%.     

Autonomous mobile robot proprioceptive navigation and predictive trajectory tracking

For an autonomous mobile robot a novel predictive control algorithm is presented, that enables both trajectory tracking and point stabilization. This algorithm is employed in conjunction with a proprioceptive navigation algorithm using either inertial or odometric data for posture estimation according to detected slip conditions. Based on the latter, slip control is made possible. Experimental results demonstrate the performance of the system.     

Marsokhod: Autonomous navigation tests on a Mars-like terrain

This paper describes the Russian rover Marsokhod, designed by Babakin Center for Mars exploration and the navigation sub-system based on stereovision developed by the French Space Agency C.N.E.S. to provide the rover with autonomous motion ability, improving thus its exploration range on the surface of Mars. Tests of the complete vehicle, including autonomous locomotion, has been recently fulfilled on a Mars-like area build in C.N.E.S. for this purpose by a joined Russian-French team; the main results and conclusions of these test are related.