• 전기학회논문지
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• 제67권7호
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• pp.871-877
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• 2018

In this paper, we propose a triple nested PID control scheme for stable hovering of a quadrotor and propose a complementary filter based sensor fusion technique to improve the performance of attitude, altitude and velocity measurement. The triple nested controller has a structure in which a double nested attitude controller that has the angular velocity PD controller in inner loop and the angular PI controller in outer loop, is nested in a velocity control loop to enable stable hovering even in the case of disturbance. We also propose a sensor fusion technique by applying a complementary filter in order to reduce the noise and drift error included in the acceleration and gyro sensor and to measure the velocity by fusing image, gyro, and acceleration sensor. In order to verity the performance, we applied the proposed control and measurement scheme to hovering control of quadrotor.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.703-710
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• 2007

This paper presents an attitude determination scheme for the Science and Technology Satellite-2(STSAT-2) using Fine Digital Sun Sensor(FDSS). The FDSS has been developed for STSAT-2, and exhibits the accuracy of 0.032degree in $1{\sigma}$. To be specific, the attitude information from the sensor is exploited to compensate for Fiber Optic Gyro(FOG) mounted on STSAT-2, and Kalman filter model is derived and implemented. To show the effectiveness of the present compensation scheme, computer simulations have been carried out resulting in the attitude errors within a bound.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.553-558
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• 2002

Physical sensor model in pushbroom satellite images can be made from sensor modeling by rotation parameters and attitude parameters on the satellite track. These parameters are determined by the information obtained from GPS, INS, or star tracker. Provided from satellite image, an auxiliary data error is connected directly with an error of rotation parameters and attitude parameters. This paper analyzed how obtaining satellite images influenced errors of rotation parameters and attitude parameters. furthermore, for detailed analysis, this paper generated simulated satellite image, which was changed variously by rotation parameters and attitude parameters of satellite sensor model. Simulated satellite image is generated by using high-resolution digital aerial image and DEM (Digital Elevation Model) data. Moreover, this paper determined correlation of rotation parameter and attitude parameters through error analysis of simulated satellite image that was generated by various rotation parameters and attitude parameters.

• 제어로봇시스템학회논문지
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• 제14권9호
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• pp.881-885
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• 2008

To calculate the attitude in ARS(Attitude Reference System) using 3 gyros and 3 accelerometers, gyro drift must be compensated with accelerometer to avoid divergence of attitude error. Kalman filter is most popular method to integrate those two sensor outputs. In this paper, new Kalman filtering method is proposed for roll and pitch attitude estimation. New states are defined to make linear equation and algorithm for changing Kalman filter parameters is proposed to ignore disturbances of acceleration. This algorithm can be easily applied to low cost ARS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.274-277
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• 2002

This paper deals with the attitude determination using GPS carrier phase. The main factors on attitude reliability are accuracy, error factors and the real-time ambiguity resolution speed. Firstly, these factors are reviewed. And then, the attitude reliability is improved by applying the averaging method. Finally, the attitude determination software is verified by the experiments. The accuracy of the proposed attitude determination method is 0.013$^{\circ}$ PE in live test. This result is more accurate than the existing INS equipment.

• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.522-526
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• 2015

Generally, underwater unmanned vehicle have adopted an inertial navigation system (INS), dead reckoning (DR), acoustic navigation and geophysical navigation techniques as the navigation method because GPS does not work in deep underwater environment. Even if the tactical inertial sensor can provide very detail measurement during long operation time, it is not suitable to use the tactical inertial sensor for small size and low cost UUV because the tactical inertial sensor is expensive and large. One alternative to INS is attitude heading reference system (AHRS) with the micro-machined electro mechanical system (MEMS) inertial sensor because of MEMS inertial sensor's small size and low power requirement. A cost effective and small size attitude heading reference system (AHRS) which incorporates measurements from 3-axis micro-machined electro mechanical system (MEMS) gyroscopes, accelerometers, and 3-axis magnetometers has been developed to provide a complete attitude solution for UUV. The AHRS based MEMS overcome many problems that have inhibited the adoption of inertial system for small UUV such as cost, size and power consumption. Several evaluation experiments were carried out for the validation of the developed AHRS's function and these experiments results are presented. Experiments results prove the fact that the developed MEMS AHRS satisfied the required specification.

• Journal of Astronomy and Space Sciences
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• 제12권2호
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• pp.256-264
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• 1995

This report presents the development procedure and the results of a prototype star sensor which can be used as one of the attitude sensors of the KITSAT-3. The star sensor is a major attitude sensor that can determine the 3-axis attitude information, by comparing between star corrdinates in the star catalog and the measured corrdinates. The 2 dimensional CCD camera is used for measuring the star corrdinates and the DSP(Digital Signal Processor) technology is applied to the image and signal processing. Using the prototype star sensor with thermoelectri cooling technique, we have succesfully obtained the star images around 4th magnitude at Sobaeksan Astronomy Observatory minimizing night sky effect.

• 한국군사과학기술학회지
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• 제23권6호
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• pp.565-573
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• 2020

Unlike fin-stabilized projectiles, there has been some difficulty measuring the attitudes of spin-stabilized projectiles during the long-range flight due to their high spin rates. In this work, solar and geomagnetic sensors were used to measure the attitude of a spin-stabilized projectile. A method to calculate the attitude of the projectile from the signals of the sensors was introduced as well as the methods to process the signals of the sensors. To validate the methods, the attitude of a projectile was calculated with the sensor signals from the actual flight data.

• 대한원격탐사학회지
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• 제22권1호
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• pp.63-73
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• 2006

Currently, in order to achieve accurate geolocation of satellite images we need to generate control points from individual scenes. This requirement increases the cost and processing time of satellite mapping greatly. In this paper we investigate the feasibility of modeling entire image strips that has been acquired from the same orbital segments. We tested sensor models based on satellite orbit and attitude with different sets of unknowns. We checked the accuracy of orbit modeling by establishing sensor models of one scene using control points extracted from the scene and by applying the models to adjacent scenes within the same orbital segments. Results indicated that modeling of individual scenes with $2^{nd}$ order unknowns was recommended. In this case, unknown parameters were position biases, drifts, accelerations and attitude biases. Results also indicated that modeling of orbital segments with zero-degree unknowns was recommended. In this case, unknown parameters were attitude biases.

• Journal of Astronomy and Space Sciences
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• 제10권1호
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• pp.1-16
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• 1993

Three typer of spin-axis attitude determination program for the geosynchronous transfer orbit spacecraft are developed. Deterministic closed-from algorithm, batch least-square algorithm and stabilized Kalman filter algorithm are used for implemetation of three programs. EUROSTAR bus model from British Aerospace is used for attitude sensor modelling. Attitude determinations using three programs are performed for the simulated sensor data according to INMARSAT 2-F1 prelaunch mission analysis.