• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.52-52
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• 2000

The HPL(Horizontal Protection Limit) means bound of radial horizontal error with given probability in satellite navigation system. RAIM algorithm is not available if HPL exceeds HAL (Horizontal Alert Limit). So exact calculation of HPL is very significant in RAIM algorithm. In this paper the methods that calculate HPL their own way a]:e studied and compared by simulation. And availability of RAIM algorithm is evaluated also.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.3
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• pp.49-56
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• 2012

Performance analysis on RAIM, which is one of the techniques for monitoring integrity to ensure the reliability of GPS, was conducted in this study. RAIM is such a method which allows its user to monitor integrity in the stand-alone mode. Among the existing RAIM procedures, the representative methods including the RCM (Range Comparison Method), LSRM (Least Square Residual Method), Parity approach and WRAIM (Weighted RAIM) were evaluated, and their performance was analyzed. To validate the performance of the implemented algorithms, fault detection was tried on the clock malfunctioning event of PRN 23 occurred on January 1st, 2004. As a result, it was identified that the LSRM and the WRAIM detected all the faults happened in the event. In the case of RCM, all the states of fault were detected except for the error which occurred as a false alarm at one epoch. Furthermore, simulated biases were added for each satellite to analyze the sensitivity of each algorithm. Consequently, when biases of the 9-13 meters range were simulated for the RCM and LSRM algorithm, all the malfunctions were detected. For the WRAIM method, it could detect range biases greater than 15 meters.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.194-194
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• 2000

In aviation navigation by GPS, requirements on availability and integrity must be absolutely satisfied for safety. Current study on accomplishing this integrity includes RAM(Receiver Autonomous Integrity Monitoring), checking integrity internally in GPS receiver itself. However RAIM techniques have be investigated and presented under assumption that there is included only one fault in measurements from GPS, In case of multiple fault, an interaction among bias errors sometimes results in decreasing the effect of multiple fault. This may make an exact fault detection and identification difficult, and study on mutiple fault RAIM focused on. This paper explains the reasons that techniques applied on single fault are not adequate to extend directly to two faults case and shows that RAIM solution on two fault may be given in revised parity space.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.593-601
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• 2012

This paper develops and analyzes a new multiple-hypothesis Receiver Autonomous Integrity Monitoring (RAIM) algorithm as a candidate for future standard architecture. The proposed algorithm can handle simultaneous multiple failures as well as a single failure. It uses measurement residuals and satellite observation matrices of several consecutive epochs for Failure Detection and Exclusion (FDE). The proposed algorithm redueces the Minimum Detectable Bias (MDB) via the Relative RAIM (RRAIM) scheme. Simulation results show that the proposed algorithm can detect and filter out multiple failures in tens of meters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.52-60
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• 2003

In aviation navigation using GPS, requirements on availability and integrity must be absolutely satisfied. Current study on accomplishing this integrity includes RAIM(Receiver Autonomous Integrity Monitoring), monitoring integrity internaIly in GPS receiver itself. Parity space technique as one of RAIM techniques has shown the advantages in fault detection and isolation due to each use of its magnitude and direction under the assumption of one fault. ln case of multiple fault, as biases in errors interact decreasing the effect of multiple fault in parity space, the exact fault detection and identification(FDI) may be difficult to be conducted. This paper focuses on FDI study on two faults and explains why parity space techniques applied on single fault is not adequate to the application of multiple fault case and shows that extended parity space technique may improve the performance of RAIM on two faults.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.786-789
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• 2004

With the development of RAIM techniques for single failure. there has been increasing interest in the multiple failure problem. There have been many approaches to tackle the problem from various points of view. This paper approaches to two failure problem with total least squares (TLS) technique, which has rarely been addressed because TLS requires a great number of computations.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.774-777
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• 2004

RAIM techniques based on TLS have rarely born addressed because TLS requires a great number of computations. In this paper, the special form of the observation matrix H, that is, one column is exactly known, is exploited so as to develop a new TLS-based sequential algorithm to identify an errant satellite. The algorithm makes us enjoy the advantages of TLS with less computational burden. The proposed algorithm is verified through a numerical simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.56.4-56
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• 2001

Using GPS in the navigation systems such as aviation, maritime and land applications, integrity is considered importantly with accuracy for safety. Integrity monitoring performed in the GPS receiver itself is Receiver Autonomous Integrity Monitoring (RAIM) and need not an independent ground monitoring station. RAIM algorithm uses redundant information when more than four satellites are visible and makes consistency checks between measurement information to alarm users whether the system is operating out of its specified performance limits. Selective Availability (SA) that was used to protect the security interests of the U.S. and its allies by globally denying the full accuracy of the civil system was turned off on May 1, 2000 ...

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.781-789
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• 2010

In the GPS/INS integrated system fault detection, algorithm based on a chi-square distribution is commonly used. In this paper, it has been proposed simplified GPS/INS fault detection algorithm that is combined conventional RAIM (Receiver Autonomous Integrity Monitor) and algorithm based on chi-square distribution for UAV using row-grade processor. It use a fault model to verify the proposed algorithm and produced the result.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.627-632
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• 2005

RAIM techniques based on TLS have rarely been addressed because TLS requires a great number of computations. In this paper, the particular form of the observation matrix H, is exploited so as to develop a new TLS-based sequential algorithm to identify an errant satellite. The algorithm allows us to enjoy the advantages of TLS with less computational burden. The proposed algorithm is verified through a numerical simulation.