• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.676-679
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• 1996

In this paper, the uniform observability and the error characteristics for stationary SDINS error are analyzed. The use of the Lyapunov transformation is proposed for transforming te conventional SDINS error model and the sufficient conditions for the uniform observability of SDINS error model are analytically derived. A complete characterization for the SDINS error characteristics during two position alignment is presented which allows us to predict the performance of two position alignment in SDINS.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.860-863
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• 1996

In this paper, we formulate the extended Kalman filter for calibration of gimballed inertial navigation system (GINS) at a pure navigation mode with 1500 ft/sec initial velocity and compare its performance to the linear Kalman filter's by using Monte-Carlo analysis method. It has been shown that estimation performance of the extended Kalman filter is better than that of the linear Kalman filter.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.82-82
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• 2000

The way which estimates a position from Navigation is Dead-reckoning Navigation and Radio Navigation. Generally dead-reckoning navigation uses Gyro and odometer as sensor, but these have problems which are an integrating noise and a noise-sensitivity. Gps which is used by radio-navigation has a Troposthetic error and MultiPath ewer and so on. For minimizing a Troposthetic error and a Multipath error, this paper suggests to an algorithm which use vanishing point on CCD camera.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.368-371
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• 2009

The GALILEO Project is to be the one and only European Global Navigation Satellite System(GNSS). The GIVE-B satellite, a second experimental GALILEO satellite was launched and started the transmission of ranging signals. GIOVE-B satellite is intended as a trueprototype of future GALILEO satellite. So I introduce the standard deviation of code multi path, signal power, antennas performance and L1-E5 group delay etc. Therefore I comprehend the current progress and tend of GALILEO Project and try to propose the national countremeasures.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.425-428
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• 2008

To overcome the limitation of tracking speed on signal-shaded area and the discontinuity of GPS, we present a system which estimates the speed of moving object using GPS and accelerometer. This system is designed to correct accelerometer's noises which are caused by vibration and impact to the object and errors of itself, from the navigation information of GPS receiver and accelerometer which are installed to moving object. And using this information, it estimates the speed of moving object on GPS signal-shaded area to complement discontinuity of GPS navigation information. We designed Kalman Filter structure using GPS and accelerometer to apply this system, and verify that the system can estimate object's speed on GPS signal-shaded area. Finally, we present the possibilities applying to telematics systems like automatic navigation system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.2
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• pp.101-108
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• 2005

Inertial Navigation System has been used extensively to determine the position, velocity and attitude of the body. An INS is very expensive, however, heavy, power intensive, requires long setting times and the accuracy of the system is degraded as time passed due to the accumulated error. Global Positioning System(GPS) receivers can compensate for the Inertial Navigation System with the ability to provide both absolute position and attitude. This study describes a method to improve both the accuracy of a body positioning and the precision of an attitude determination using GPS antenna array. Existing attitude determination methods using low-cost GPS receivers focused on the relative vectors between the master and the slave antennas. Then the positioning of the master antenna is determined in meter-level because the single point positioning with pseudorange measurements is used. To obtain a better positioning accuracy of the body in this research, a wireless internet is used as an alternative data link for the real-time differential corrections and dual-frequency GPS receivers which is expected to be inexpensive was used. The numerical results show that this system has the centimeter level accuracy in positioning and the degree level accuracy in attitude.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1C
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• pp.123-129
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• 2010

In this paper, we analyze the code tracking biases of single and double early-minus-late processing schemes which are widely used code tracking method for global navigation satellite systems. The code tracking bias which results from the distortion in symmetry of correlation values is arisen in the presence of multipath signals. To analyze them, two civil signals which are spreading signals modulated by binary phase shift keying and binary offset carrier are considered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.74-80
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• 2006

GPS, which has been opened to the public since the 1980's, uses the C/A code time of arrival to estimate the position, and measures the carrier doppler frequency to estimate the velocity. In development from the 1990's, DGPS has improved position accuracy by eliminating common errors and CDGPS has achieved cm-level position accuracy using carrier phase. In this paper, a modified LSAST ambiguity resolution method for CDGPS is proposed to improve reliability and computational efficiency. Also the test results of cm level relative positioning of a moving vehicle using single frequency GPS receivers are compared to INS position. This research result can be widely used for the development of high precision INS, unmanned autonomous driving, survey and mapping, etc.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.48-55
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• 2006

Performance characteristics of the position-domain Hatch filter is analyzed for differential global navigation satellite systems. It is shown that the position-domain Hatch filter generates white measurement residual sequences, which is beneficial property for fault detection. It is also shown that the position-domain Hatch filter yields more accurate a priori state estimate than the position-domain Kalman-type filter. Thus, it can be concluded that the position-domain Hatch filter is beneficial in wide application areas where fault-tolerance and accuracy are required at the same time.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.518-524
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• 2011

This paper presents a study on the calibration of accelerometer data in the gyroscope free inertial navigation system(GFINS) using fuzzy inference system(FIS). The conventional INS(inertial navigation system) which can measure yaw rate and linear velocity using inertial sensors as the gyroscope and accelerometer. However, the INS is difficult to design as small size and low power because it uses the gyroscope. To solve the problem, the GFINS which does not have the gyroscope have been studied actively. However, the GFINS has cumulative error problem still. Hence, this paper proposes Fuzzy-GFINS which can calibrate the data of an accelerometer using FIS consists of two inputs that are ratio between linear velocity of the autonomous ground vehicle(AGV) and the accelerometer and ratio between linear velocity of the encoders and the accelerometer. To evaluate the proposed Fuzzy-GFINS, we made the AGV with Mecanum wheels and applied the proposed Fuzzy-GFINS. In experimental result, we verified that the proposed method can calibrate effectively data of the accelerometer in the GFINS.