GPS 반송파 위상변화율을 이용한 SDINS/GPS 복합항법 필터 구성

박준구(Joon-Goo Park) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.11

SDINS 운항중 정렬에 적용 가능한 GPS 반송파 위상변화율 측정 모델을 유도하여 새로운 SDINS/GPS 복합항법 시스템 구성 방법을 제안한다. 제안된 SDINS/GPS 복합항법 필터의 성능 분석을 공분산 해석기법을 이용하여 수행하고 이의 결과를 실제 차량 실험을 통하여 검증한다. 제안된 결합기법은 2개 이상의 안테나를 갖는 SDINS/GPS 결합시스템에 적용가능하며 기수각 추정에 직접적으로 연계된 GPS 측정치를 생성함으로써 빠른 SDINS의 기수각 추정을 가능하게 함으로써 SDINS/GPS의 항법 성능을 향상시키게 된다. As an application of SDINS/GPS integration for its synergistic results, the SDINS alignments utilizing GPS carrier phase rate measurements. A measurement model of GPS carrier phase rate is derived in order to be used with SDINS alignment process. For in-flight alignment, the performance of the suggested SDINS/GPS integration method is analyzed using the covariance analysis and its results are confirmed by those of van test. Consequently, it is shown that all states of the SDINS integrated system by utilizing GPS carrier phase rate measurements can be estimated more efficiently than a general SDINS/GPS during in-flight alignment

약결합 방식의 SDINS/별센서/수평센서 보정항법 알고리즘 설계 및 시스템 검증

김태영,방효충,이창용,조윤철 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.4

관성센서(IMU)를 이용한 관성항법기법(SDINS)은 짧은 운용시간 내에 높은 정확도의 독립적인 항법해를 계산해 준다는 장점이 있지만, 센서 내부의 바이어스(Bias) 및 랜덤오차(Random walk)로 인해 시간에 지남에 따라 항법 오차가 발산하는 단점이 있다. 이러한 관성항법장치의 오차보정은 GPS 및 광학센서와 같은 외부센서를 SDINS와 결합함으로써 성취 될 수 있으며, 그 중 가장 정밀하고 높은 신뢰도의 보정정보를 제공하는 별센서를 결합한 SDINS 보정항법 알고리즘 설계를 수행하였다. 본 논문에서 제시하는 SDINS/별센서/수평센서 복합 항법 시스템은 별센서로부터 계산된 자세 및 위치오차 정보들을 융합칼만필터(Kalman Filter)의 측정치로 입력받아 SDINS의 항법해 오차를 보상하는 방식으로 구성된다. Because Strapdown Inertial Navigation System (SDINS) offers the independent navigation solution with high accuracy only in a short operating time due to the bias and random walk of inertial sensors, the error correction must be performed by external sensors such as GPS or optical sensor for high precision and long period navigation. The aim of this paper is to design and implement a loosely coupled form of SDINS/Star Tracker/Horizon Sensor integrated navigation algorithm. The integrated navigation system receives the precise attitude and position information from a star sensor as a measure of the Kalman Filter and compensates the errors of the SDINS navigation solution.

UKF를 이용한 발사체의 SDINS/별센서 통합 항법시스템 성능개선

김태영,방효충,조윤철 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

고속으로 비행하는 발사체의 항법해를 높은 정확도로 추정하기 위해서는 SDINS/별센서 결합 보정항법 시스템 모델의 비선형성(Non-linearity) 문제를 해결하는 것이 중요하다. 이러한 비선형성은 일반적으로 불규칙한 지구표면형상(Irregular Earth Surface Shape) 및 달, 태양에 의한 중력섭동(Gravitational Perturbation) 등에 의한 중력가속도 편차(Gravitational Acceleration Deviation)로부터 기인하며, SDINS/별센서 통합 항법시스템의 정확도를 떨어트리는 주된 요인으로 작용한다. 따라서 본 논문에서는 대표적인 비선형 필터인 UKF(Unscented Kalman Filter)를 이용하여 이러한 비선형성 문제를 해결하였으며, 별센서로부터 계산된 관성자세 정보들을 융합 칼만필터의 측정치로 입력받아 SDINS 항법해 오차 보정 성능을 개선하였다. 최종적으로 시뮬레이션을 통해 정밀하고 높은 신뢰도의 항법해를 제공하는 UKF 기반의 SDINS/별센서 보정항법 알고리즘을 검증하였다. Because Strapdown Inertial Navigation System (SDINS) offers the independent navigation solution with high accuracy only in a short operating time due to the bias and random walk of inertial sensors, the error correction must be performed by external sensors such as GPS or optical sensor for high precision and long period navigation. The aim of this paper is to design and implement a loosely coupled form of SDINS/Star Tracker/Horizon Sensor integrated navigation algorithm. The integrated navigation system receives the precise attitude and position information from a star sensor as a measure of the Kalman Filter and compensates the errors of the SDINS navigation solution.

뱅크턴하는 항체에 대한 GPS를 이용한 SDINS의 자세 오차 추정 향상

유해성(Haesung Yu),유기정(Ki-Jeong Yoo),김현석(Hyun-Seok Kim),이윤선(Youn Seon Lee),박흥원(Heung-Won Park) 한국항공우주학회 2011 韓國航空宇宙學會誌 Vol.39 No.2

뱅크턴을 수행하는 항공기에 운용되는 관성항법장치의 특정 자이로 비정렬 오차가 수직축 자세오차를 연속적으로 증가시키는 현상에 대해서 분석을 수행하고, 이 자아로 비정렬 오차를 제거하기 위해 GPS을 결합한 INS/GPS 시스템에 대해서 새로운 비정렬 모델링 방법을 제시하고, 그 성능 향상을 시뮬레이션을 통해 제시한다. An approach to improve the performance of SDINS and GPS integrated system for bank-to-turn flight vehicles is described. Then, it is shown through the simulation that a specific gyro misalignment error results in an increased heading error of SDINS. A new modelling method is presented herein for identifying of sensor and attitude error. The main advantage of the proposed method is that it not only estimates the gyro misalignment error of SDINS, but also improves estimate performance of heading error of SDINS in the presence of the gyro misalignments.

링레이저 자이로 기반 관성항법장치와 위성항법장치의 강결합 방식 시스템 구현

유해성(Haesung Yu),박상은(Sang Eun Park),정진섭(Jinseob Jeong),박흥원(Heung-Won Park) 한국항공우주학회 2013 韓國航空宇宙學會誌 Vol.41 No.2

항공기에 탑재되어 운용되는 링레이저 자이로 기반 스트랩다운 관성항법장치(SDINS)와 위성항법장치(GPS)의 결합 시스템의 실시간 구현에 있어서 설계시 고려해야할 문제에 대해서 살펴본다. SDINS/GPS 결합 시스템의 실시간 구현시, 레버암, 측정치 획득 및 오차 보상 외에, 링 레이저 자이로 기반의 SDINS의 특성을 고려해야만 한다. 뱅크턴을 반복적으로 수행하는 항공기에서 발생하는 누적 수직축 자세 오차를 추정하기 위해, 자이로의 비정렬이 모델링된 모델을 구현한다. 항공기 탑재 시험을 통해 수직축 자세 오차의 누적 문제 및 실시간 구현 상의 문제를 해결하고, 자세 오차 추정 성능 향상 결과를 살펴본다. This paper explores a real-time system implementation to couple tightly StrapDown Inertial Navigation System(SDINS) and Global Positioning System(GPS) mounted on the aircraft. When implementing the SDINS/GPS coupled system in real-time processor, we have to deliberate SDINS’s unique characteristics based on the ring laser gyro, and besides, lever-arm, measurements, and error compensation method. The novel modeling method is applied to system the misalignment error term of gyro to estimate the cumulative heading attitude errors while the aircraft banking to turn repeatedly. Captive Flight Test results show that the proposed modeling strategy has good performance.

일반공산비 기법을 이용한 SDINS/GPS 통합시스템의 고장 검출 및 격리

신정훈,임유철,유준,Shin, Jeong-Hoon,Lim, You-Chol,Lyou, Joon 한국군사과학기술학회 2000 한국군사과학기술학회지 Vol.3 No.2

This paper presents a fault detection and isolation(FDI) method based on Generalized Likelihood Ratio(GLR) test for the tightly coupled SDINS/CPS system. The GLR test is known to have the capability of detecting an assumed change while estimating its occurrence time and magnitude, and isolating the changing part. Once a fault is detected even if we don't know if the fault occurrs at either INS or GPS, multi-hypothesized GLR scheme performs the fault isolation between INS and GPS, and find which satellite malfunctions. However, in the INS faulty case, it turned out to fail to accomodate the fault isolation between accelerometer and gyroscope due to the coupling effects and a poor observability of the system. Hence, to isolate the INS fault, it needs to change the attitude of the vehicle resulting in enhancing the degree of observability.

A Theoretical Approach to Observability Analysis of the SDINS/GPS in Maneuvering with Horizontal Constant Velocity

유영민,박찬국,박준구,이달호 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.2

A theoretical method for analyzing the observability of a strapdown inertial navigation system (SDINS) integrated with the global positioning system (GPS) is proposed. The analysis is performed based on two types of maneuvers for a vehicle on a horizontal trajectory: level flight with constant north velocity and level flight with constant east velocity. The observability also is analyzed using the convergence theorem, stationary state observability analysis results, and Kalman filter measurement information to rearrange the SDINS error model equation. The state variables are divided into observable and unobservable parts, and determine which state variables are observable and estimable with some errors from the relationship of observable and unobservable state variables. Our results have shown that the north and east axes accelerometer bias errors were unobservable, and that attitude errors, and east and down axes gyro bias errors were estimable with some unknown bias errors. It has been shown that horizontal maneuvering improves the observability of down axis gyro bias error compared with the stationary state, and the estimation errors of the heading error state and east axis gyro bias error are dependent on the magnitude of north velocity. The results of the theoretical observability analysis are confirmed through computer simulation.

A Multistage In-flight Alignment with No Initial Attitude References for Strapdown Inertial Navigation Systems

홍운선,박찬국 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.3

This paper presents a multistage in-flight alignment (MIFA) method for a strapdown inertial navigation system (SDINS) suitable for moving vehicles with no initial attitude references. A SDINS mounted on a moving vehicle frequently loses attitude information for many reasons, and it makes solving navigation equations impossible because the true motion is coupled with an undefined vehicle attitude. To determine the attitude in such a situation, MIFA consists of three stages: a coarse horizontal attitude, coarse heading, and fine attitude with adaptive Kalman navigation filter (AKNF) in order. In the coarse horizontal alignment, the pitch and roll are coarsely estimated from the second order damping loop with an input of acceleration differences between the SDINS and GPS. To enhance estimation accuracy, the acceleration is smoothed by a scalar filter to reflect the true dynamics of a vehicle, and the effects of the scalar filter gains are analyzed. Then the coarse heading is determined from the GPS tracking angle and yaw increment of the SDINS. The attitude from these two stages is fed back to the initial values of the AKNF. To reduce the estimated bias errors of inertial sensors, special emphasis is given to the timing synchronization effects for the measurement of AKNF. With various real flight tests using an UH60 helicopter, it is proved that MIFA provides a dramatic position error improvement compared to the conventional gyro compass alignment.

A Multistage In-flight Alignment with No Initial Attitude References for Strapdown Inertial Navigation Systems

Hong, WoonSeon,Park, Chan Gook The Korean Society for Aeronautical and Space Scie 2017 International Journal of Aeronautical and Space Sc Vol.18 No.3

This paper presents a multistage in-flight alignment (MIFA) method for a strapdown inertial navigation system (SDINS) suitable for moving vehicles with no initial attitude references. A SDINS mounted on a moving vehicle frequently loses attitude information for many reasons, and it makes solving navigation equations impossible because the true motion is coupled with an undefined vehicle attitude. To determine the attitude in such a situation, MIFA consists of three stages: a coarse horizontal attitude, coarse heading, and fine attitude with adaptive Kalman navigation filter (AKNF) in order. In the coarse horizontal alignment, the pitch and roll are coarsely estimated from the second order damping loop with an input of acceleration differences between the SDINS and GPS. To enhance estimation accuracy, the acceleration is smoothed by a scalar filter to reflect the true dynamics of a vehicle, and the effects of the scalar filter gains are analyzed. Then the coarse heading is determined from the GPS tracking angle and yaw increment of the SDINS. The attitude from these two stages is fed back to the initial values of the AKNF. To reduce the estimated bias errors of inertial sensors, special emphasis is given to the timing synchronization effects for the measurement of AKNF. With various real flight tests using an UH60 helicopter, it is proved that MIFA provides a dramatic position error improvement compared to the conventional gyro compass alignment.

A Multistage In-flight Alignment with No Initial Attitude References for Strapdown Inertial Navigation Systems

WoonSeon Hong,Chan Gook Park 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.3

This paper presents a multistage in-flight alignment (MIFA) method for a strapdown inertial navigation system (SDINS) suitable for moving vehicles with no initial attitude references. A SDINS mounted on a moving vehicle frequently loses attitude information for many reasons, and it makes solving navigation equations impossible because the true motion is coupled with an undefined vehicle attitude. To determine the attitude in such a situation, MIFA consists of three stages: a coarse horizontal attitude, coarse heading, and fine attitude with adaptive Kalman navigation filter (AKNF) in order. In the coarse horizontal alignment, the pitch and roll are coarsely estimated from the second order damping loop with an input of acceleration differences between the SDINS and GPS. To enhance estimation accuracy, the acceleration is smoothed by a scalar filter to reflect the true dynamics of a vehicle, and the effects of the scalar filter gains are analyzed. Then the coarse heading is determined from the GPS tracking angle and yaw increment of the SDINS. The attitude from these two stages is fed back to the initial values of the AKNF. To reduce the estimated bias errors of inertial sensors, special emphasis is given to the timing synchronization effects for the measurement of AKNF. With various real flight tests using an UH60 helicopter, it is proved that MIFA provides a dramatic position error improvement compared to the conventional gyro compass alignment.