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Prox-1 University-Class Mission to Demonstrate Automated Proximity Operations

JOURNAL OF SPACECRAFT AND ROCKETS 2016年第5期53卷 847-863页

作者： Spencer, David A. Chait, Sean B. Schulte, Peter Z. Okseniuk, Kevin J. Veto, Michael Georgia Inst Technol Sch Aerosp Engn Atlanta GA 30332 USA Arizona State Univ Sch Earth & Space Explorat Tempe AZ 85281 USA

The Georgia Institute of Technology Prox-1 mission will demonstrate automated trajectory control in low Earth orbit relative to the deployed LightSail 2 CubeSat for an on-orbit inspection application. Passive thermal imaging provides the basis for a relative navigation system used to provide state estimation and optical tracking of LightSail 2. Automated maneuver planning and execution uses a guidance algorithm based upon relative orbital elements, with persistent collision avoidance using an artificial potential function. Simulation of the closed-loop guidance, navigation, and control system shows that the system is capable of performing automated station-keeping and relative orbit transfers for close-proximity operations. Funded by the U.S. Air Force Office of Scientific Research/ U.S. Air Force Research Laboratory through the University Nanosatellite Program-7, Prox-1 is scheduled to launch in September 2016 as a secondary payload on the Space Test Program-2 launch.

关键词： Small Satellites Air Force Research Laboratory navigation algorithm Resident Space Object Obstacle Avoidance GNC Systems Air Forces Optical Tracking Control Moment Gyroscope ISS

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Optimal Threshold Setting for Event-Based Control Strategies

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IEEE ACCESS 2017年 5卷 2880-2893页

作者： Socas, Rafael Dormido, Sebastian Dormido, Raquel Univ Nacl Educ Distancia Dept Informat & Automat E-28040 Madrid Spain

In this paper, an event-based control strategy for mobile robots is proposed. The solution includes new features that minimize the effects of the noise on the system. Two methodologies have been developed to compensate the perturbations. To avoid the effects of such perturbations, a threshold calculator and a perturbation estimator are included in the system. The proposed system is compared with classical control systems based on discrete time. Different scenarios are analyzed in the experiments to check its performance. The stability and the improvements of the proposed control strategy are also analyzed in the experimental results.

关键词： Mobile robots event-based control dynamic threshold setting navigation algorithm perturbation estimation

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The Epoch-State Filter, Revisited

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2023年第7期46卷 1228-1242页

作者： Carpenter, J. Russell NASA Goddard Space Flight Ctr Space Sci Mission Operat Tech Code 444 Greenbelt MD 20771 USA

The epoch-state filter is a recursive sequential estimator that maintains its state estimate and associated covariance at a fixed time known as the epoch, avoiding the need to propagate the covariance between measurements. Instead, the filter maps measurement innovations from the measurement time to the epoch time, in a fashion similar to a batch estimator. When process noise is present, the epoch time must follow all but at most the penultimate measurement. Revisiting the topic, this paper contributes several variations, including a factorized form, a factorized information form, and sigma-point versions, and provides a number of clarifying illustrative examples.

关键词： Kalman Filter algorithms and Data Structures Mathematical Analysis Celestial Mechanics Satellites Computing and Informatics navigation algorithm

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Accuracy improvement in motion-measurement using frequency-weighted Kalman filter

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IET RADAR SONAR AND navigation 2020年第1期14卷 89-96页

作者： Shaghaghian, Alireza Karimaghaee, Paknoosh Shiraz Univ Sch Elect & Comp Engn Shiraz Iran

Accurate antenna motion-measurement is an essential pre-condition for synthetic aperture radar (SAR) to produce well-focused images. The measurement accuracy at high and low frequencies affects the quality of images and the geolocation error. Hence, motion compensation and focusing techniques require a minimum degree of accuracy in the radar motion measurements. The Inertial Measurement Unit (IMU) sensor selection process is done based on the SAR parametric requirements. The IMU instruments have inherent limited precision and accuracy, which are significantly related to the technology and the cost. The navigation algorithm may improve the precision and accuracy to overcome the limitations of the IMU sensor. This study intends to improve motion measurement accuracy using frequency-weighted state estimation. The proposed algorithm shows an error reduction in state estimation and an improvement in some parameter indices which are in relation to SAR image quality and geolocation. Two innovative algorithms are proposed in this study. The first one is the frequency-weighted Kalman filter which is an improved form of the Kalman filter. Another one is multi-resolution decomposition which is an approach to evaluate the SAR motion measurement system.

关键词： synthetic aperture radar radar imaging state estimation radar antennas Kalman filters motion compensation motion measurement frequency-weighted Kalman filter accurate antenna motion-measurement essential pre-condition synthetic aperture radar well-focused images high frequencies geolocation error motion compensation focusing techniques radar motion measurements Inertial Measurement Unit sensor selection process SAR parametric requirements IMU instruments navigation algorithm IMU sensor motion measurement accuracy frequency-weighted state estimation error reduction improved form SAR motion measurement system

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Adaptive Control of Precision Guided Airdrop Systems with Highly Uncertain Dynamics

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2018年第5期41卷 1025-1035页

作者： Cacan, Martin R. Costello, Mark Georgia Inst Technol Woodruff Sch Mech Engn Ctr Adv Machine Mobil Atlanta GA 30322 USA Georgia Inst Technol Auton Guggenheim Sch Aerosp Engn Atlanta GA 30322 USA

The bulk of research in the field of precision guided airdrop systems has focused on improving landing accuracy in the presence of atmospheric winds that can exceed vehicle airspeed. One important challenge of parafoil systems is their highly uncertain flight dynamic behavior and control response, which can result from canopy degradation or an offnominal inflation event. This significantly impacts the ability to reach the target and can often lead to very large miss distances. This work addresses guided airdrop system model uncertainty with a novel combined direct and indirect adaptive control strategy to quickly characterize vehicle dynamics and lateral control sensitivity in flight. Extensive simulation and experimental flight testing indicate that the proposed adaptive algorithm is capable of high-accuracy landing in a large variety of degraded conditions, including unknown nonlinear changes in control sensitivity as well as control reversals. In comparison, current industry standard algorithms experience over an order of magnitude decrease in accuracy when tested under identical scenarios.

关键词： Adaptive Control algorithm Parafoil Experimental Flight Test Airspeed Control Reversal Adaptive algorithm navigation algorithm GPS Multiple Input Multiple Output algorithms Ability

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Covariance Estimation and Gaussianity Assessment for State and Measurement Noise

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2020年第1期43卷 132-139页

作者： Dunik, Jindrich Kost, Oliver Straka, Ondrej Blasch, Erik Univ West Bohemia Dept Cybernet Univ 8 Plzen 30614 Czech Republic US Air Force Res Lab Rome NY 13441 USA

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Event Triggers in Linear Covariance Analysis with Applications to Orbital Rendezvous

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2009年第1期32卷 102-111页

作者： Geller, David K. Ben Rose, M. Woffinden, David C. Utah State Univ Logan UT 84322 USA

The analytic expressions for a generic event trigger for a linear covariance analysis are developed. The event triggers are applied to the analysis of a common orbital rendezvous problem. Some unexpected results are observed and a flaw in an equation that is commonly used in standard linear covariance analysis applications is uncovered and remedied. A quantitative analysis of the effect of elevation-angle triggers for various rendezvous scenarios is presented.

关键词： Earth Orbital Rendezvous Orbital Transfer Monte Carlo Simulation Flight Computer Resident Space Object LIDAR Targeting algorithms White Noise navigation algorithm Dirac Delta Function

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INS algorithm using quaternon model for low cost IMU

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ROBOTICS AND AUTONOMOUS SYSTEMS 2004年第4期46卷 221-246页

作者： Kong, XY Univ Technol Sydney Fac Engn Sydney NSW 2007 Australia

This paper presents a generic inertial navigation system (INS) error propagation model that does not rely on small misalignment angles assumption. The modelling uses quaternions in the computer frame approach. Based on this model, an INS algorithm is developed for low cost inertial measurement unit (IMU) to solve the initial attitudes uncertainty using in-motion alignment. The distribution approximation filter (DAF) is used to implement the non-linear data fusion algorithm. (C) 2004 Elsevier B.V. All rights reserved.

关键词： quaternion inertial navigation system global positioning system navigation algorithm

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Study on Robust Lateral Controller for Differential GPS-Based Autonomous Vehicles

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INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING 2018年第3期19卷 367-376页

作者： Park, Hyung-Gyu Ahn, Kyoung-Kwan Park, Myeong-Kwan Lee, Seok-Hee Univ Ulsan Sch Mech Engn 93 Daehak Ro Ulsan 44610 South Korea Pusan Natl Univ Grad Sch Mech Engn 2Busandaehak Ro 63beon Gil Busan 46241 South Korea

Recently, technological advancements in autonomous vehicle development have continued to accelerate. In this paper, we propose a lateral controller and navigation algorithm for autonomous vehicles based on the Differential Global Positioning System (DGPS), core technology of autonomous vehicles. In this study, an H-infinity (H-a) controller was designed lateral controller to ensure nominal safety and robustness against noise, external disturbances and structural and non-structural errors in vehicle modeling. Meanwhile, the "pure pursuit" approach which geometrically follows a path was employed as a path-tracking technique for the proposed navigation algorithm. A vehicle modeling simulation was conducted to evaluate the performance of the proposed method using a twodegrees- of-freedom linear model. The lateral H-a controller and navigation algorithm were applied to an actual vehicle, Their performances were evaluated by comparing the path tracking error at various speeds of autonomous vehicles with that of the proportional-integral-derivative (PID) controller.

关键词： Lateral control Robust controller Unmanned vehicle navigation algorithm Bicycle model Path tracking

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Autonomous Exploration of a Small Near-Earth Asteroid

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2021年第4期44卷 701-718页

作者： Takahashi, Shota Scheeres, Daniel J. Univ Colorado Ann & HJ Smead Aerosp Engn Sci Dept 3775 Discovery Dr Boulder CO 80309 USA

Asteroid exploration missions must deal with large uncertainties in a target body's gravity and shape as well as ephemeris errors upon rendezvous. navigation and guidance are typically performed using ground-based operations, which can be costly. This paper studies the possibility of removing the ground in the process through onboard navigation with optical measurements and accelerometer-based.V measurements. The paper first describes the dynamics and measurement models used to simulate a spacecraft's interaction with the asteroid environment, followed by implementation details of navigation and guidance subsystems. The paper then presents a covariance analysis of this problem using simplified dynamics, focusing on the information content of the optical and.V measurements. Guided by this, an end-to-end autonomous exploration scheme with onboard navigation and eventdriven orbit control is analyzed through simulation, introducing realistic errors between the truth and filter dynamics. The basic operations of this scheme are built around near-inertial hovering and include approach from the end of an interplanetary phase, reconnaissance at various viewing geometries, close gravity estimation, and orbit insertion. The feasibility of the proposed autonomous navigation and orbit control is evaluated using a Monte Carlo analysis and is shown to be robust.

关键词： Asteroids Earth Accelerometer Monte Carlo Simulation Autonomous navigation Extended Kalman Filter navigation algorithm Newton Raphson Method Dirac Delta Function Interplanetary Trajectories

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