Line-of-sight pointing accuracy/stability analysis and computer simulation for small spacecraft

1996 ◽  
Author(s):  
Marcelo C. Algrain ◽  
Richard M. Powers
Keyword(s):  
Computer Simulation ◽  
Stability Analysis ◽  
Line Of Sight ◽  
Small Spacecraft ◽  
Pointing Accuracy

scholarly journals Line of Sight and Image Motion Compensation for Step and Stare Imaging System

2020 ◽  
Vol 10 (20) ◽  
pp. 7119
Author(s):  
Jihong Xiu ◽  
Pu Huang ◽  
Jun Li ◽  
Hongwen Zhang ◽  
Youyi Li
Keyword(s):  
High Resolution ◽  
Motion Compensation ◽  
Imaging System ◽  
Control Flow ◽  
Image Motion ◽  
Line Of Sight ◽  
Pointing Accuracy ◽  
High Resolution Images ◽  
Pointing Control ◽  
And Control

In recent years, applications such as marine search and rescue, border patrol, etc. require electro-optical equipment to have both high resolution and precise geographic positioning abilities. The step and stare working based on a composite control system is a preferred solution. This paper proposed a step and stare system composed of two single-axis fast steering mirrors and a two-axis gimbal. The fast steering mirrors (FSMs) realize image motion compensation and the gimbal completes pointing control. The working principle and the working mode of the system are described first. According to the imaging optical path, the algorithm and control flow of the line of sight (LOS) and image motion compensation are developed. The proposed method is verified through ground imaging and flight tests. Under the condition of flight, the pointing accuracy of the target can be controlled within 15 m. The proposed algorithm can achieve effective motion compensation and get high-resolution images. This achieves high resolution and accurate LOS simultaneously.

The Evaluation of Agreement Between Dynamics of Electric Wheelchair and Human Behavior

2004 ◽  
Vol 16 (4) ◽  
pp. 434-442 ◽  
Author(s):  
Shigenobu Shimada ◽  
◽  
Kosei Ishimura ◽  
Mitsuo Wada ◽  
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Stability Analysis ◽  
Human Behavior ◽  
User Behavior ◽  
Electric Wheelchair ◽  
Straight Line ◽  
Almost All

We studied the problem of interaction of movement between the electric wheelchair and the user. Almost all current products have indexes such as roll stability and operability, but such indexes do not always agree with user behavior because such indexes are static. Another problem arises from the fact that the disagreement of movement causes uncontrollable situations and turnover of the wheelchairs. We evaluated wheelchairs that consider user behavior, first in an experiment to understand the cause of disagreement among users during movement by measuring straight line ands turning, then, based on this result, derived a mathematical model for disagreement in wheelchair motion. Computer simulation, showed that vibration occurred within certain parameters. We present simple roll stability analysis of wheelchairs turning. Simulation confirmed the viability of our proposals.

Probabilistic Approach to Stability Analysis of a Reinforced Concrete Retaining Wall

2014 ◽  
Vol 1079-1080 ◽  
pp. 248-251
Author(s):  
David Pustka
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Reinforced Concrete ◽  
Stability Analysis ◽  
Structural Optimization ◽  
Reliability Analysis ◽  
Retaining Wall ◽  
Rapid Development ◽  
Probabilistic Approach ◽  
Simulation Monte Carlo

Rapid development of computer technologies brings possibility to exploitpowerful computers for reliability analysis of (civil) engineering structuresunder consideration of random properties of various quantities influencingtheir resulting reliabilities. Aim of this paper is to outline possibility ofutilization of computer simulation Monte Carlo to predict reliability of areinforced concrete retaining wall from the viewpoint of possible loss ofstability. One of advantages of this approach is possibility to quantifyprobability of failure allowing structural optimization leading to design ofmore effective structures.

scholarly journals Landing stability analysis for lunar landers using computer simulation experiments

2017 ◽  
Vol 14 (6) ◽  
pp. 172988141774844 ◽  
Author(s):  
Yuanyuan Liu ◽  
Shunguang Song ◽  
Ming Li ◽  
Chunjie Wang
Keyword(s):  
Computer Simulation ◽  
Stability Analysis ◽  
Simulation Experiments

Guidance laws based on model predictive control and target manoeuvre estimator

2016 ◽  
Vol 38 (12) ◽  
pp. 1509-1519 ◽  
Author(s):  
Shaoming He ◽  
Defu Lin
Keyword(s):  
Stability Analysis ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Angular Rate ◽  
Tracking Error ◽  
Small Region ◽  
Line Of Sight ◽  
Guidance Law ◽  
Angle Tracking ◽  
Guidance Laws

A new composite guidance law for intercepting manoeuvring targets with desired terminal line-of-sight (LOS) angle constraint is proposed in this paper. The presented guidance law is derived through generalized model predictive control (GMPC) augmented by a target manoeuvre estimator. More specifically, the target manoeuvre estimator is used to estimate and compensate for the unknown target manoeuvre online while the GMPC is used to obtain optimal LOS angle tracking performance. Stability analysis shows that the LOS angle tracking error and the LOS angular rate can converge to a sufficiently small region around zero asymptotically. The effectiveness of the proposed guidance law is validated by applying it to a surface-to-air missile for intercepting a head-on manoeuvring target under different scenarios.

scholarly journals CONDOR observations of high mass star formation in Orion

2006 ◽  
Vol 2 (S237) ◽  
pp. 492-492
Author(s):  
N. H. Volgenau ◽  
M. C. Wiedner ◽  
G. Wieching ◽  
M. Emprechtinger ◽  
F. Bielau ◽  
...  
Keyword(s):  
High Mass ◽  
Main Beam ◽  
Line Of Sight ◽  
Mass Star ◽  
The Moon ◽  
Beam Structure ◽  
Atmospheric Transmission ◽  
Pointing Accuracy ◽  
Atmospheric Windows ◽  
Better Than

CONDOR, the CO, N+, Deuterium Observations Receiver, is designed to make velocity-resolved observations of the CO, [NII], and p-H2D+ lines in the 1.4 THz (200-240μm) atmospheric windows. CONDOR's first light observations were made with the APEX telescope in November 2005. The CONDOR beam on APEX (at ν = 1.5 THz) was expected to consist of a 4.3″ main beam and a 73″ error beam; this beam structure was verified from scans of Mars. The pointing accuracy, also determined from Mars scans, was better than 7″. The average atmospheric transmission during our Orion observations (elev~57°) was 19 ± 4% along the line-of-sight. A forward efficiency of Feff = 0.8 was determined from sky dips, and observations of the Moon and Mars were used to couple the CONDOR beam to sources of different sizes (ηc = 0.40 and ~0.10, respectively). For more information, see Wiedner et al. 2006.

Stability Analysis of an Initially Inclined Ship in Following Sea

2000 ◽  
Vol 67 (4) ◽  
pp. 717-719 ◽  
Author(s):  
S. K. Lee
Keyword(s):  
Computer Simulation ◽  
Stability Analysis ◽  
Longitudinal Wave ◽  
Roll Motion ◽  
Parametric Oscillation ◽  
Loss Of Stability ◽  
Longitudinal Waves ◽  
Analytic Expression ◽  
Ship Capsizing

Generally speaking, the causes of ship capsizing in waves are due to the pure loss of stability, parametric oscillation, and broaching-to phenomenon. In this paper, an analytic expression for the GZ value of a ship, inclined initially by some reasons like damage in longitudinal waves, is derived. And, the roll motion is calculated through the computer simulation to give the necessary information for the safe regions of various parameters of a ship moving in a longitudinal wave. [S0021-8936(00)00704-2]

Sign in / Sign up

Export Citation Format

Share Document