Attitude Determination by External Vectors in Airplane Free Spin Investigation

2020 ◽  
Vol 28 (3) ◽  
pp. 43-59
Author(s):  
A.V. Vyalkov ◽  
Keyword(s):  
Attitude Determination ◽  
Vertical Wind ◽  
Rotation Vector ◽  
Finite Rotation ◽  
Kinematic Parameters ◽  
Body Frame ◽  
Aircraft Model ◽  
External Reference

The article gives an overview of the methods for determining orientation angles from observations of external reference vectors. To maintain the observability of the kinematic parameters of the free-flying aircraft model motion in a vertical wind tun-nel, we analyzed the methods for determining the finite rotation vector using two, three or more vectors, known in a model body frame, as well as their derivatives. The methods to estimate the reliability of the calculated orientation angles are proposed. The method for estimating the radius of the free-flying model spin is considered.

scholarly journals A Direct Attitude Determination Approach Based on GPS Double-Difference Carrier Phase Measurements

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Jianhua Cheng ◽  
Jing Wang ◽  
Lin Zhao
Keyword(s):  
Carrier Phase ◽  
Attitude Determination ◽  
Double Difference ◽  
Body Frame ◽  
Phase Equation ◽  
New Approach ◽  
Solution Approach ◽  
Relationship Of ◽  
The Relationship ◽  
Attitude Matrix

The principle of the traditional attitude solution approach based on GPS (Global Position System) is to get the attitude matrix according to the relationship of coordinates. During the progress, the error of baseline position assumed in ECEF (Earth-Centered Earth-Fixed) and the error of coordinate transform between body frame and reference frame (ENU, East-North-Up) have been included in the result, and finally the precision of attitude determination is reduced. This contribution presents a new approach of attitude determination, in which the attitude angles are calculated by the double-difference carrier phase equation of GPS according to the relationship of attitude matrix and attitude angles through least-squares estimate method. The new approach predigests the procedure of attitude determination which reduces the error assumed. According to the analysis the precision of attitude determination is higher than that of traditional method. It is shown it gets a precise attitude result with the direct attitude determination method in the simulation. A novel algorithm is proposed to solve some problems. Simulation results show the effectiveness of the proposed algorithm.

Flight Test of Attitude Determination System using Multiple GPS Antennae

2005 ◽  
Vol 59 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Jaegyu Jang ◽  
Changdon Kee
Keyword(s):  
Navigation System ◽  
Attitude Determination ◽  
Phase Measurement ◽  
Angular Rate ◽  
Flight Test ◽  
The Body ◽  
Body Frame ◽  
Carrier Phase Measurement ◽  
External Interference ◽  
Determination System

Small Unmanned Aerial Vehicles (UAVs) or inexpensive airplanes, such as a Cessna single engine aircraft, require a navigation system with a cheap, compact and precise sensor. Over the past ten years, GPS receivers have begun to be used as primary or alternative navigation sensors, because their use can significantly reduce the overall system cost. This paper describes a navigation system incorporating a velocity-based attitude estimation system with an attitude determination system using multiple antennae, which was implemented and tested using a UAV. The main objective was to obtain precise attitude information using low cost GPS OEM boards and antennae. Attitude boundaries are derived from the relationship between the body frame and the wind coordinates, which are used to validate the resolved cycle ambiguity in an Euler angle domain. Angular rate based on Doppler measurements was used to exclude the degenerate pseudo-roll angle information during severe uncoordinated flight. Searching for cycle ambiguity at every epoch of the flight showed that the developed system gave reliable cycle integer solutions, although the carrier phase measurement was subject to additional errors, such as multipath, external interference, and phase centre variation. A flight test was performed using a 1/4-scale Piper J3 Cub model, CMC Allstar OEM boards, OEM AT575-70 antennae, and 700 MHz PC104 board.

scholarly journals Geometric Parameter Calibration for a Cable-Driven Parallel Robot Based on a Single One-Dimensional Laser Distance Sensor Measurement and Experimental Modeling

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2392 ◽  
Author(s):  
XueJun Jin ◽  
Jinwoo Jung ◽  
Seong Ko ◽  
Eunpyo Choi ◽  
Jong-Oh Park ◽  
...  
Keyword(s):  
Position Control ◽  
Uncertainty Modeling ◽  
Parallel Robot ◽  
Parallel Robots ◽  
The Body ◽  
Robot Kinematics ◽  
Kinematic Parameters ◽  
Body Frame ◽  
Geometric Uncertainty ◽  
Calibration Methods

A cable-driven parallel robot has benefits of wide workspace, high payload, and high dynamic response owing to its light cable actuator utilization. For wide workspace applications, in particular, the body frame becomes large to cover the wide workspace that causes robot kinematic errors resulting from geometric uncertainty. However, appropriate sensors as well as inexpensive and easy calibration methods to measure the actual robot kinematic parameters are not currently available. Hence, we present a calibration sensor device and an auto-calibration methodology for the over-constrained cable-driven parallel robots using one-dimension laser distance sensors attached to the robot end-effector, to overcome the robot geometric uncertainty and to implement precise robot control. A novel calibration workflow with five phases—preparation, modeling, measuring, identification, and adjustment—is proposed. The proposed calibration algorithms cover the cable-driven parallel robot kinematics, as well as uncertainty modeling such as cable elongation and pulley kinematics. We performed extensive simulations and experiments to verify the performance of the suggested method using the MINI cable robot. The experimental results show that the kinematic parameters can be identified correctly with 0.92 mm accuracy, and the robot position control accuracy is increased by 58%. Finally, we verified that the developed calibration sensor devices and the calibration methodology are applicable to the massive-size cable-driven parallel robot system.

Least Squares Method for Attitude Determination Using the Real Data of CBERS-2 Satellite

2014 ◽  
Vol 706 ◽  
pp. 181-190 ◽  
Author(s):  
W.R. Silva ◽  
H.K. Kuga ◽  
M.C. Zanardi ◽  
R.V. Garcia
Keyword(s):  
Reference System ◽  
Attitude Determination ◽  
Least Squares Method ◽  
Real Data ◽  
The Body ◽  
Space Environment ◽  
Artificial Satellites ◽  
Body Frame ◽  
Control Center ◽  
Yaw Attitude

his work is applied to the dynamics of rotational motion of artificial satellites, that is, itsorientation (attitude) with respect to an inertial reference system. The attitude determination involvesapproaches of nonlinear estimation techniques, which knowledge is essential to the safety and controlof the satellite and payload. Here one focuses on determining the attitude of a real satellite: CBERS-2(China Brazil Earth Resources Satellite). This satellite was launched in 2003 and were controlled andoperated in turns by China (Xi’an Control Center) and Brazil (Satellite Control Center). Its orbit isnear polar sun-synchronous with an altitude of 778km, crossing Equator at 10:30am in descendingdirection, frozen perigee at 90 degrees, and providing global coverage of the world every 26 days.The attitude dynamical model is described by nonlinear equations involving the Euler angles. Theattitude sensors available are two DSS (Digital Sun Sensor), two IRES (Infra-Red Earth Sensor), andone triad of mechanical gyros. The two IRES give direct measurements of roll and pitch angles with acertain level of error. The two DSS are nonlinear functions of roll, pitch, and yaw attitude angles. Thegyros furnish the angular measurements in the body frame reference system. Gyros are very importantsensors, as they provide direct incremental angles or angular velocities. They can sense instantaneousvariations of nominal velocities. An important feature is that it allows the replacement of complexmodels (different torques acting on the space environment) by using their measurements to turn thedynamical equations into simple kinematic equations. However gyros present several sources of errorof which the drift is the most troublesome. Such drifts yield along time an accumulation of errorswhich must be accounted for in the attitude determination process. Herein one proposes to estimatethe attitude and the drift of the gyros using the Least SquaresMethod. Results show that one can reachaccuracies in attitude determination within the prescribed requirements, besides providing estimatesof the gyro drifts which can be further used to enhance the gyro error model.

scholarly journals A Fast in-Motion Alignment Algorithm for DVL Aided SINS

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Li Kang ◽  
Lingyun Ye ◽  
Kaichen Song
Keyword(s):  
Attitude Determination ◽  
Unscented Kalman Filter ◽  
Integral Form ◽  
The Body ◽  
Doppler Velocity ◽  
Alignment Algorithm ◽  
Body Frame ◽  
Attitude Error ◽  
Motion Condition ◽  
Alignment Problem

Doppler velocity log (DVL) aided strapdown inertial navigation system (SINS) is a common navigation method for underwater applications. Owing to the in-motion condition and the lack of the GPS, it is a challenge to align a SINS under water. This paper proposed a complete in-motion alignment solution for both attitude and position. The velocity update equation and its integral form in the body frame are studied, and the attitude coarse alignment becomes an optimization-based attitude determination problem between the body frame velocity and the integral form of gravity. The body frame velocity and the Earth frame position are separately treated, and the position alignment problem turns into an equation solving problem. Simulation and on-lake tests are carried out to examine the algorithm. The heading could reach around 10 deg accuracy and the pitch and roll could be aligned up to 0.05 deg in 60 s. With attitude error of this level, the heading could reach 1 deg accuracy in 240 s using unscented Kalman filter (UKF) based fine alignment. The final position error could achieve 1.5% of the voyage distance. This scheme can also be applied to other body frame velocity aided SINS alignments.

scholarly journals Time integration of rigid bodies modelled with three rotation parameters

2021 ◽  
Author(s):  
Stefan Holzinger ◽  
Johannes Gerstmayr
Keyword(s):  
Lie Group ◽  
Attitude Determination ◽  
Time Integration ◽  
Rigid Bodies ◽  
Singular Points ◽  
Rotation Vector ◽  
Euler Angles ◽  
Euler Parameters ◽  
Time Step ◽  
Rotation Parameters

AbstractThree rotation parameters are commonly used in multibody dynamics or in spacecraft attitude determination to represent large spatial rotations. It is well known, however, that the direct time integration of kinematic equations with three rotation parameters is not possible in singular points. In standard formulations based on three rotation parameters, singular points are avoided, for example, by applying reparametrization strategies during the time integration of the kinematic equations. As an alternative, Euler parameters are commonly used to avoid singular points. State-of-the-art approaches use Lie group methods, specifically integrators, to model large rigid body rotations. However, the former methods are based on additional information, e.g. the rotation matrix, which must be computed in each time step. Thus, the latter method is difficult to incorporate into existing codes that are based on three rotation parameters. In this contribution, a novel approach for solving rotational kinematics in terms of three rotation parameters is presented. The proposed approach is illustrated by the example of the rotation vector and the Euler angles. In the proposed approach, Lie group time integration methods are used to compute consistent updates for the rotation vector or the Euler angles in each time step and therefore singular points can be surmounted and the accuracy is higher as compared to the direct time integration of rotation parameters. The proposed update formulas can be easily integrated into existing codes that use either the rotation vector or Euler angles. The advantages of the proposed approach are demonstrated with two numerical examples.

Attitude determination sensor for low Earth orbit satellite based on Lorentz force

2018 ◽  
Vol 233 (6) ◽  
pp. 2219-2230 ◽  
Author(s):  
Mohsen Rezaei ◽  
Kamran Raissi ◽  
Hamed Hashemi Mehne ◽  
Yaser Norouzi
Keyword(s):  
Magnetic Field ◽  
Lorentz Force ◽  
Attitude Control ◽  
High Speed ◽  
Attitude Determination ◽  
Low Earth Orbit ◽  
The Body ◽  
Body Frame ◽  
Specific Frequency ◽  
Better Than

Spacecraft attitude determination is a crucial task in attitude control subsystems. It provides the necessary feedback to close the control loop. Several sensors such as star trackers, Sun sensors, and horizon sensors are used for this purpose. The development of other methods can help control engineer with newer options to design their systems. Here, an innovative sensor for determining the attitude of a spacecraft is presented. The proposed sensor measures the Lorentz force vector due to the interaction between the magnetic field of the Earth, and the high linear velocity of the spacecraft. This sensor is composed of three series of orthogonal variable capacitors. The capacitors are connected in parallel to increase the total capacitance. The capacitors have movable plates which actuated by alternating current with specific frequency. Due to very high speed of spacecraft relative to magnetic field of earth in low orbit, the Lorentz force is exerted on the charges of the capacitor plates. The plates have same velocity as the spacecraft does. The applied Lorentz force to the plates affects their motion so that the harmonic can be seen in the output. Measuring the amplitude of the mentioned harmonic results in measurement of a component of the Lorentz force in the direction of capacitors. Installing the three capacitors orthogonally can measure the three rectangular components of the Lorentz force. This vector will be in the body frame of the spacecraft. The two-plate and three-plate capacitor are the two different proposed mechanisms and their performance is compared. Once the Lorentz force is known as a vector in the body frame, it can be applied along with data from another sensor to determine the attitude of the spacecraft. Based on simulation results, achievable resolution is better than 3°, which can be improved by further research.

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