• 한국정밀공학회지
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• 제4권4호
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• pp.56-71
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• 1987

Determination of navigation variables (latitude, longitude, and altitude) near the earth's surface is termed 'Terrestrial Navigation'. The quantities that are measured inertially are the total acceleration (or the integral fo this acceleration over a fixed time interval) and the total angular rate (or the integral of this angular rate over the same time interval). These measurements when suitably compensated can be manipulated to yield the navigation variables. Hence, it is essential that the initial values of position, orientation and velocity are accurately set up during the initial alignment process. Initial alignment of gimballed inertial navigation system ( GINS) is accomplished by gyrocompassing techniques. These cannot be used, in the case of strapdown inertial navigation system(SDINS), where the inertial instruments are directly strapped down to a vehicle frame. The basic objective of this paper is the development of digital method for the determination of the initial axes erection of a SDINS from vibration and sway currupted data on the launch pad.

• 제어로봇시스템학회논문지
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• 제20권4호
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• pp.468-473
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• 2014

This paper describes the in-flight alignment of SDINS (Strapdown Inertial Navigation Systems) using an EKF (Extended Kalman Filter) and a UKF (Unscented Kalam Filter), which allow large initial attitude error uncertainty. Regardless of the inertial sensors, there are nonlinear error dynamics of SDINS in cases of large initial attitude errors. A UKF that is one of the nonlinear filtering approaches for IFA (In-Flight Alignment) are used to estimate the attitude errors. Even though the EKF linearized model makes velocity errors when predicting incorrectly in case of large attitude errors, a UKF can represent correctly the velocity errors variations of attitude errors with nonlinear attitude error components. Simulation results and analyses show that a UKF works well to handle large initial attitude errors of SDINS and the alignment error attitude estimation performance are quite improved.

• 제어로봇시스템학회논문지
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• 제21권7호
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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.

• 한국군사과학기술학회지
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• 제6권1호
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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.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3703-3716
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• 2022

Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.142-146
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• 1991

In order to develope transfer alignment algorithm which achieves accurate initial alignment of slave strapdown inertial navigation system(SDINS) of a missle using master SDINS of mobile launchers third-order suboptimal filter is constructed to estimate the transformation matrix between two SDINS coordinates. In Kalman Filter formulation, the measurement equation uses that of accelerometer when stationary, and is replaced by that of gyroscope when elevating the missle. This switching method is applied to increase the degree of observability and to remove the error generated by lever arm effect. Simulation results show that the azimuth transfer error is about 0.3 mrad, and confirm that this scheme has a potential for real application.

• 대한교통학회지
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• 제25권2호
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• pp.157-165
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• 2007

본 연구에서는 GPS(Global Positioning System), INS(Inertial Navigation System), DMI(Distance Measuring Unit) 등 각종 센서를 장착한 차량을 이용하여 차량의 위치정보와 자세정보를 취득하고, 취득된 차량의 주행정보를 이용하여 도로 종단선형을 분석할 수 있는 알고리즘을 개발하였다. 개발된 종단선형 분석 알고리즘은 도로의 종단경사, 종단곡선 시종점 및 도로 종단곡선 길이 등을 분석할 수 있고, 종단경사와 종단곡선을 모형화하였다. 또 개발한 알고리즘의 현장 적용성을 검증하기 위하여, 실제 도로에서 취득한 데이터를 이용하여 종단선형을 분석하였고, 이 결과를 도면과 비교하였다.

• 한국항공우주학회지
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• 제36권11호
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• pp.1079-1086
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• 2008

관성항법장치 초기정렬 방법인 전달정렬의 경우 MINS에서 SINS로 전송되는 데이터에는 변동하는 시간지연이 존재한다. 이러한 시간지연은 전달정렬의 성능을 저하시킨다. 본 논문에서는 측정치 잉여값을 이용하여 실시간으로 시간지연 공분산값을 추정하여 시간지연 추정오차를 줄이는 적응필터를 제시하고 수직발사 SDINS 전달정렬에 적용하여 확장형 칼만필터의 성능과 비교하였다. 시뮬레이션 결과 배운동이 크게 변할수록 적응필터의 성능이 확장형 칼만필터보다 더 우수한 것으로 나타났다.

• 한국군사과학기술학회지
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• 제21권3호
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• pp.349-360
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• 2018

This paper proposes various methods for constructing a HWIL simulation system including Inertial Navigation System(INS) and Guidance Control Unit(GCU) under the assumption that the INS identifies the initial attitude of an aviation body through its own alignment and that it is a package consisting of an inertial sensor and a navigation computation module. This paper also presents a real-time computing technology and a way to calculate the command of the Flight Motion System(FMS) analogous to the acutal flight environment. The proposed HWIL simulation system is constructed by applying the above-mentioned methods and the results of running a series of simulations confirm high effectiveness and usefulness of the system. Finally, minor error factors that could be acquired only in HWIL simulation Environment are analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.29-33
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• 1993

This paper suggests Kalman filter formulation using by precision GINS output angle for SDINS initial transfer alignment of missile. The Kalman filter model was derived from quaternion parameters and the transfer alignment system by angle matching method satisfies azimuth observability in horizontal angular motion. The estimated error of SDINS attitude settles to less 3mrad(1.sigma.) in 200 seconds at proper sea state.