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基于天文角度观测的机载惯性/天文组合滤波算法研究 总被引:2,自引:0,他引:2
针对采用天文/惯性位置组合时对导航选星有特殊要求,提出了基于天文角度观测信息的机载惯性/天文组合滤波方案及算法.对基于天文角度观测的INS/CNS组合导航系统的原理进行了充分阐述,分析并建立了基于单星或多星观测条件下的组合导航系统线性化量测方程,并针对角度观测时高度通道不可观的特点,增加了气压高度输出为系统的观测量,并在此基础上设计了组合滤波器算法.最后进行了组合导航系统仿真,并通过协方差分析的方法对比分析了单星和双星观测条件下的滤波性能.仿真结果表明,即使是在单星观测条件下,组合导航系统也能获得较好的定位精度;若观测星数增多,则可以大大提高系统性能,表明该组合导航系统设计方案是成功可行的. 相似文献
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An analysis of characteristics of autonomous navigation by using optical sighting of unknown landmarks was carried out for artificial satellites in circular orbits around the Earth with altitudes from 300 to 900 km. It is shown that navigational errors vary approximately in inverse proportion to duration of measurements. Also they decrease with an increasing number of sighted landmarks. The errors poorly depend on the orbit altitude if the duration of measurement for each landmark is chosen in proportion to the orbit altitude, or a maximal zenith angle of sighting the landmark remains constant.Some characteristics of the navigational algorithm are given. Admissible deviations of initial orbital elements from their exact values are investigated. For a properly chosen measurement procedure the algorithm proves to be stable even for rather crudely given initial parameters. 相似文献
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导航系统的性能与其可观测性密切相关,而可观测矩阵是分析导航系统可观测性能的重要依据。本文基于分段线性定常系统(PWCS)方法给出导航系统的可观测矩阵,进而针对测角测速组合导航系统开展可观测性分析。通过分析测角测速组合导航系统可观测矩阵的秩和条件数,得到导航系统的可观测性和整体可观测度,并研究导航系统的可观测阶数对导航系统的影响;同时基于奇异值分解(SVD)方法给出测角测速组合导航系统各个状态分量的可观测性分析方法。最后,以小行星探测工程任务巡航段为背景,系统地给出了不同量测模型的导航系统可观测性结果,分析了不同可观测性分析方法对导航系统可观测性刻画的适用性。本文所提出的可观测性分析方法,对导航系统可观测性分析具有很好的参考性,可为组合导航系统量测模型的优选提供参考,具有良好的理论和应用价值。 相似文献
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传统的三角形星图识别算法冗余匹配多,对噪声鲁棒性差,为此,在传统三角形算法的基础上,提出了一种改进的算法。该算法思想如下:将观测三角形三个角距组成的平面的法向量向最优主轴投影,利用投影值进行索引,得到候选导航三角形后,利用角距进行匹配,若存在冗余匹配,再利用归一化的星等消除冗余匹配。实验结果表明:与传统的三角形算法相比,两者识别所需时间基本相同,但是改进的算法对噪声的鲁棒性更好,冗余匹配更少,识别率更高。改进的算法在质心偏差为0.5像素,星等噪声为0.5Mv时,识别率高达97.7%,传统三角形算法在质心偏差为0.5像素时,识别率仅为91.4%。 相似文献
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This study presents an experimentthat investigates how individuals perform anavigation test in a desktop virtualenvironment. The participants were randomlyassigned to one of the five test conditions:(C1) a map as information material during theentire test, (C2) the map only visible beforethe test, (C3) textual information during theentire test, (C4) textual information onlybefore the test and (C5) no additionalnavigational cues. The results were thatadditional information during the entire testwas more effective than short periods ofstudying the map or textual information onlybefore the test. However, participants weremore accurate in finding their route when anykind of navigational cues were used than whenno navigational cues were used. The results ofan additional questionnaire indicate thatbetween the test groups there were nodifferences in estimating the travelleddistances. The performance to draw the coveredpath into a sketch map of the landscape did notdiffer significantly between the test groupswith additional navigational cues. Theseresults indicate that in certain environmentstextual information may provide an effectivealternative to navigation training with a map. 相似文献
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针对弹群协同编队飞行中,编队成员单独使用惯导系统(INS)时存在定位误差发散的问题,基于相同性能的多套INS在相同环境下工作时,其误差近似呈零均值高斯分布这一特性,提出了一种利用成像导引头对航路上任一未知地标被动观测的弹群INS定位误差协同修正方法。首先,融合弹群中各枚导弹相对于地标的视线角量测信息及INS位置量测信息,利用最小二乘思想对未知地标进行协同定位;然后,基于估计得到的地标位置,利用各枚导弹相对于地标的视线角和方位角速率量测信息及INS速度量测信息,反过来修正弹群中各枚导弹的INS定位误差。最后,仿真验证了方法的有效性。 相似文献
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Optical navigation for guidance and control of robotic systems is a well-established technique from both theoretic and practical points of view. According to the positioning of the camera, the problem can be approached in two ways: the first one, “hand-in-eye”, deals with a fixed camera, external to the robot, which allows to determine the position of the target object to be reached. The second one, “eye-in-hand”, consists in a camera accommodated on the end-effector of the manipulator. Here, the target object position is not determined in an absolute reference frame, but with respect to the image plane of the mobile camera. In this paper, the algorithms and the test campaign applied to the case of the planar multibody manipulator developed in the Guidance and Navigation Lab at the University of Rome La Sapienza are reported with respect to the eye-in-hand case. In fact, being the space environment the target application for this research activity, it is quite difficult to imagine a fixed, non-floating camera in the case of an orbital grasping maneuver. The classic approach of Image Base Visual Servoing considers the evaluation of the control actions directly on the basis of the error between the current image of a feature and the image of the same feature in a final desired configuration. Both simulation and experimental tests show that such a classic approach can fail when navigation errors and actuation delays are included. Moreover, changing light conditions or the presence of unexpected obstacles can lead to a camera failure in target acquisition. In order to overcome these two problems, a Modified Image Based Visual Servoing algorithm and an Extended Kalman Filtering for feature position estimation are developed and applied. In particular, the filtering shows a quite good performance if target's depth information is supplied. A simple procedure for estimating initial target depth is therefore developed and tested. As a result of the application of all the novel approaches proposed, the experimental test campaign shows a remarkable increase in the robustness of the guidance, navigation and control systems. 相似文献
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捷联惯导与小视场星跟踪器构成惯性/天文组合导航系统,核心思想是利用星体跟踪器的高精度测角信息设计滤波修正算法对捷联惯导的导航姿态、方位和位置误差进行滤波估计并修正,以限制捷联惯导系统导航误差随时间的发散,最终提高系统长航时导航的导航精度。在分析小视场星体跟踪器量测量与SINS导航误差之间关系的基础上,设计了两种不同的组合导航算法:位置+方位修正算法和误差角组合导航修正算法。在此基础上对两种算法的导航精度进行了理论分析,并通过长航时仿真飞行数据进行了仿真验证。结果表明:位置+方位修正算法不受载体的位置误差的影响,更适用于星体跟踪器间断工作的情况;误差角组合算法不受载体姿态误差的影响,更适用于SINS初始位置误差得到有效修正的情况。 相似文献
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航天飞行器控制系统误差实时补偿方案研究 总被引:3,自引:0,他引:3
箭上计算机实时计算因惯性器件系统误差而造成的测速误差,并将其引入导航方程后,通过导引和关机进行实时补偿。数学仿真表明采用这种补偿方案,箭载计算机的计算工作量小,补偿精度高,是一种有实用价值的方案。 相似文献
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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. 相似文献
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This paper studies the autonomous navigation method for a group of satellites based on relative position measurements, which can be obtained by using inter-satellite links for measuring relative range and navigation star sensors for measuring relative bearing. For the satellites that are far from each other, it may be difficult to obtain relative bearing measurement due to poor visibility. To address this difficulty, this paper proposes a novel scheme, where three satellites, whose relative ranges are rather small such that the relative bearings can be observed, are used as beacons for the navigation of the other satellites that are invisible. The feasibility of the proposed navigation scheme is analyzed by using the Cramer-Rao lower bound (CRLB), with the consideration of the availability of relative bearing measurements. In addition, the multiple model adaptive estimation (MMAE) algorithm is adopted to improve the convergence speed of the estimator in the presence of large initial errors. Simulation results illustrate the high performance of the proposed scheme. 相似文献
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惯性组合导航系统中的快速景象匹配算法研究 总被引:6,自引:0,他引:6
在景象匹配辅助导航中,特征点的选取是提高图像匹配速度、精度和鲁棒性的关键之 一。景象匹配中要求提取出的特征是那些可靠性高、辨别性强、计算量小的不变特征。提出 了基于SIFT特征的导航用快速景象匹配算法。算法首先针对惯性组合导航的工作特点, 对SIFT特征点检测及特征点匹配进行了优化设计,然后用RANSAC方法过滤掉错误匹配点,最 后,进行最小二乘精确匹配算法获取航向和位置偏差信息。实验分析了算法对不同分辨率图 像和不同区域的匹配适应性,抗噪声性能,匹配精度以及实时性,并与基于部分Hausdorff 距离的边缘特征景象匹配算法进行了对比。实验结果表明,算法的性能优越,在匹配速度、 精度和鲁棒性方面都优于部分Hausdorff距离算法,可以满足景象匹配导航系统匹配修正的 高性能要求。
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