• Title/Summary/Keyword: Aircraft Alignment

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Design and Evaluation of INS Initial Alignment under Vibration Environment of Aircraft Run-up (항공기 Run-Up 진동 환경에서의 관성항법장치 초기 정렬 방법 설계 및 평가)

  • Yu, Haesung;Lee, Inseop;Oh, JuHyun;Kim, CheonJoong;Park, Heung-won
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.7
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    • pp.691-698
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    • 2015
  • Inertial Navigation Systems (INS) are widely used as the main navigation device for aircraft. To get the initial attitude, the INS requires the initial alignment before navigation starts. An aircraft also needs an engine test procedure that causes some vibrations before flight. An INS can't be aligned in a vibration environment so the initial alignment is performed before the aircraft engine test. Therefore, the initial alignment time of an INS has been a major factor in limiting an aircraft's takeoff response time. In this paper, we designed an initial alignment algorithm that can be executed even in disturbances such as aircraft run-up. We demonstrated verification of the algorithm that is embedded on the real INS and testing methods to evaluate the alignment of the INS. We also analyzed the test results of the proposed initial alignment algorithm that is performed during a real aircraft run-up.

Aircraft Survivability and Sensors Alignment Techniques (항공기의 생존성과 센서 정렬의 기술 분석)

  • Kang, J.;Lee, S.;Jun, G.;Moon, S.;Seo, S.;Lee, C.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.16 no.1
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    • pp.29-36
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    • 2008
  • The vulnerability of aircraft, especially rotary wing aircraft, has been an ongoing issue since their advent in combat operations during the 1940s. In this paper, representative sensors for survivability of those aircraft in modern battlefield are surveyed and top level requirements and parameters are defined. Also problems of multi-sensor alignment on modern agile and flexible platform are discussed and several techniques such as static alignment and transfer alignment are introduced.

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Precision Measurement for Aircraft Alignment using Industrial Photogrammetry (산업사진측량을 이용한 항공기 얼라인먼트 정밀측정)

  • Jung, Sung-Heuk;Lee, Jae-Kee
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.6
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    • pp.57-63
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    • 2005
  • According to increasing of demand for high accurate and quick measuring technology, they became to interest in industrial photogrammetry that can satisfy with this needs. This study is examined O-2A aircraft to check the application of Industrial Photogrammetry technology. To measure the aircraft alignment, the check points marked on it were used without exact aircraft design data. And to check any deformation of its external original feature, Pro-spot system has been used.

A Study of An Initial Alignment Method of Underwater Vehicle Dropped from Aircraft (항공기에서 투하되는 수중운동체의 초기정렬기법 연구)

  • 류동기;김삼수
    • Journal of the Korea Institute of Military Science and Technology
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    • v.6 no.1
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    • pp.21-29
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    • 2003
  • The Strap Down Inertial Measurement Unit(SDIMU) is recently used for the sensor package of the modern underwater vehicles such as torpedoes and unmanned underwater-vehicles. For using SDIMU, an initial alignment must be carried out before the fire or navigation stage. The general initial alignment methods require that a mother vehicle Is a stationary condition or the Inertial Navigation System(INS) of vehicle is received the specific of data navigation from the mother vehicle. But an underwater vehicle dropped from aircraft is hard to satisfy above both necessary conditions of the general initial alignment. So, we suggest a new strap down initial alignment method of an underwater vehicle dropped from aircraft without using any aided sensors. The highlight point of this method is that a period of initial alignment is not before the fire but during running stage to fix alignment error. And we verify it by analyzing various data of S/W simulations, Hardware In the Loop Simulation(HILS) tests and sea trials.

Design of Transfer Alignment Algorithm with Velocity and Azimuth Matching for the Aircraft Having Wing Flexibility (유연성을 가지는 비행체를 위한 속도/방위각 정합 전달 정렬 알고리즘 설계)

  • Suktae Kang
    • Journal of the Korea Institute of Military Science and Technology
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    • v.26 no.3
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    • pp.214-226
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    • 2023
  • A transfer alignment is used to initialize, align, and calibrate a SINS(Slave INS) using a MINS(Master INS) in motion. This paper presents an airborne transfer alignment with velocity and azimuth matching to estimate inertial sensor biases under the wing flexure influence. This study also considers the lever arm, time delay and relative orientation between MINS and SINS. The traditional transfer alignment only uses velocity matching. In contrast, this paper utilizes the azimuth matching to prevent divergence of the azimuth when the aircraft is stationary or quasi-stationary since the azimuth is less affected by the wing flexibility. The performance of the proposed Kalman filter is analyzed using two factors; one is the estimation performance of gyroscope and accelerometer bias and the other is comparing aircraft dynamics and attitude covariance. The performance of the proposed filter is verified using a long term flight test. The test results show that the proposed scheme can be effectively applied to various platforms that require airborne transfer alignment.

Improvement of Transfer Alignment Performance for Airborne EOTS (항공용 전자광학추적장비의 전달정렬 성능 개선)

  • Kim, Minsoo;Lee, Dogeun;Jeong, Chiun;Jeong, Jihee
    • Journal of Aerospace System Engineering
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    • v.16 no.4
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    • pp.60-67
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    • 2022
  • An Electro-Optical Tracking System (EOTS) is an electric optical system with EO/IR cameras, laser sensors, and an IMU. The EOTS calculates coordinates of targets, using attitude and acceleration measured by the IMU. In particular for an armed aircraft, the performance of the weapon system depends on how quickly and accurately it acquires the target coordinates. The IMU should be operated after alignment is complete, to meet the coordinate accuracy required by the weapon system so the initial stabilization time of the IMU should be reduced, by quickly measuring the attitude and acceleration. Alignment is the process of determining the initial attitude by resolving the attitude error of the IMU, and the IMU of mission equipment such as an airborne EOTS, uses velocity matching based on the velocity from GPS/INS for aircraft navigation. In this paper, a method is presented to improve the transfer alignment performance of the airborne EOTS, by maneuvering aircraft and the mission equipment. First, the performance factor of the alignment was identified, as a heading error through the velocity matching model and simulation results. Then acceleration maneuvers and attitude changes were necessary, to correct the error. As a result of flight tests applied to an EOTS on a OOO aircraft system, the transfer alignment performance was improved as the duration time was decreased, by more than five times when the aircraft accelerated by more than 0.2g and the EOTS was moving until 6.7deg/s.

Alignment of Inertial Navigation Sensor and Aircraft Fuselage Using an optical 3D Coordinate Measuring Device (광학식 3차원 좌표측정장치를 이용한 관성항법센서와 기체의 정렬기법)

  • Kim, Jeong-ho;Lee, Dae-woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.1
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    • pp.41-48
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    • 2019
  • This paper deals with a method of aligning an aircraft fuselage and an inertial navigation sensor using three-dimensional coordinates obtained by an optical method. In order to verify the feasibility, we introduce the method to accurately align the coordinate system of the inertial navigation sensor and the aircraft reference coordinate system. It is verified through simulation that reflects the error level of the measuring device. In addition, optimization method based alignment algorithm is proposed for connection between optical sensor and inertial navigation sensor.

Angular Rate and Acceleration Matching Algorithm in Aircraft in Consideration of Flexure (비행체에서 유연성을 고려한 각속도 및 가속도정합 알고리즘)

  • Yang, Cheol-Kwan;Shim, Duk-Sun
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.12
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    • pp.1126-1132
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    • 2000
  • In this paper we propose an angular rate and acceleration matching method for initial transfer alignment in aircraft. The conventional angular rate and acceleration matching method performs compensation for the lever arm effects between the master and slave INS before initial alignment. However, the conventional method does not take the flexure angular acceleration into account and thus is not effective when the flexure angular acceleration is large. We propose a new angular rate and acceleration matching method to cope with the flexure acceleration between the master and slave INS and compare the results with those of the conventional method by simulation. The simulation results show that the proposed matching method is better than the conventional matching method in case of large flexure acceleration.

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A Study of Alignment Tolerance's Definition and Test Method for Airborne Camera (항공기 탑재용 카메라 정렬오차 정의 및 시험방안 연구)

  • Song, Dae-Buem;Yoon, Yong-Eun;Lee, Hang-Bok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.2
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    • pp.154-159
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    • 2013
  • Alignment tolerance for EO/IR airborne camera using common optic is an important factor in stabilization accuracy and geo-pointing accuracy. Before airborne camera is mounted on the aircraft, defining alignment tolerance and verification of it is essential in production as well as research and development. In this paper we establish basic concept on the definition and elements of alignment tolerance for airborne camera and propose how to measure each of those elements. Components and the measurement sequence of alignment tolerance are as follows: 1) tolerance of alignment between EO and IR LOS. 2) tolerance of sensor alignment. 3) tolerance of position reporting accuracy. 4) tolerance of mount alignment

Alignment Measuring Apparatus for B-axis of Separated Multi-axis Machine (분리된 다축 장비의 B축 얼라인먼트 측정 장치에 관한 연구)

  • Cheon, Kyeong-Ho;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.4
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    • pp.47-54
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    • 2018
  • These days, the aerospace industry uses larger machining parts and assembly parts than those in the past. The assembly machines also show the same trend. This study is concerned with the alignment measuring apparatus for the B-axis of a separated multi-axis machine. The alignment measuring apparatus is widely installed for assembly machines in the aircraft assembly process. The alignment measuring apparatus consists of a swivel part and a measuring part. This is a new conceptual idea under patent. All elements of the alignment measuring apparatus are analyzed with the FEM. The analyzed result shows that the alignment measuring apparatus is high in accuracy with stability and steady deformation.