• 한국항공우주학회지
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• 제37권10호
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• pp.998-1001
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• 2009

본 논문에서는 기존의 호밍유도법칙으로 널리 사용되는 상수 항법이득을 갖는 비례항법유도법칙이 속력 변화가 있는 경우에도 엄밀한 의미에서 최적해임을 보였다. 해석결과로부터 항법상수가 3인 경우 유도항력에 접근속력이 가중된 성능지수를 최소화하는 최적해임이 확인되었다. 비행체의 운동을 선형방정식으로 표현하고 속력변화를 고려하지 않은 기존 연구결과들과 달리 본 연구에서는 비선형 방정식을 기반으로 속력변화까지 고려하여 비례항법유도법칙의 최적성에 관한 보다 일반적인 해석 결과를 제시하였다.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.141-150
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• 2021

The article assesses the level of navigation safety, in theoretical terms, defines the complexity of managing navigational risks in practice. The issues of assessing the navigational safety have been studied due to the importance and relevance of the issue in question, however, due to the great complexity of the problem under consideration, the article considers and indicates the directions for the development of the solution of the given direction, where, first of all, it became necessary to analyze the issue of assessing the levels of navigation risks when navigating vessels of various types in difficult navigation conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1736-1737
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• 2011

This paper deals with the problem of precise impact angle control of an actual homing missile guided by biased proportional navigation (BPN). To do this, the BPN guidance loop including dynamic lag is modeled as the confluent hyper-geometric differential equation and its analytic solution is derived. Based on the solution, a systematic way to determine the bias constant is newly devised. Different from the existing BPN solution obtained by ignoring the dynamic lag, the proposed one can exactly describe the behavior missile before target interception. hence it is drastically improved the angle constrained terminal guidance performance.

• 한국항해항만학회지
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• 제27권6호
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• pp.669-675
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• 2003

Using a SQUID magnetometer, the diamagnetic susceptibility of NaCl aqueous solution was measured with high accuracy in a magnetic field of up to 6 Tat 25$\pm0.05^{\circ}C$. The NaCl concentrations adopted in this experiment were 0 (water), 7.5, 15, 23, 26.2, 26.6 and 100% (crystal) with the concentration error of $\pm$0.04%. Experimental data was compared with the calculated value of susceptibility derived from dependence of the vapor pressure on NaCl concentration As a result, our measured value was almost in accordance with the calculated value. It was found that the diamagnetic susceptibility shows a decrease of approximately 10% within the saturated concentration (26.2%) and that the susceptibility is one of the effective cause for the concentration dependence in the gas-liquid interface deformation of the NaCl solution.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.114.4-114
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• 2001

Recently, variety services are more and more developed due to supply of PDA, cellular phone, and etc. Also, a services based on location information are very helpful in traffic, shopping, and emergency. Thus the user position is positively necessary for these services. One of the latest applications in GPS is the E911 call service for wireless phones. In this case, current GPS Navigation accuracy meets the FCC requirements but the hardware size and power consumption of GPS is issued for implementation. And, some case of applications need to snapshot location solution with fast TTFF(Time-To-Fist-Fix) than continuous location solution. The software GPS receiver could be the solution ...

• 한국항행학회논문지
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• 제23권6호
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• pp.526-534
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• 2019

전파 신호를 이용한 위치 추정 방법은 3개 이상의 앵커로부터 거리 측정치를 획득하여야 한다. 하지만 일반적인 건물은 좁고 기다란 복도와 모퉁이로 구성되어 있어 3개 이상의 가시 앵커를 확보하기 쉽지 않으며, 이로 인해 멀티 모달 솔루션이 발생하여 사용자의 위치를 추정하기가 어렵다. 이러한 문제를 극복하기 위해 본 논문에서는 인공신경망을 이용하여 위치를 추정하는 방법을 제안한다. 인공신경망을 이용하면 멀티 모달 솔루션이 발생하더라도 축적된 거리 측정치를 기반으로 사용자 이동 패턴 정보를 획득하여 위치를 추정할 수 있다. 해당 방법은 추가적인 장비나 센서가 필요치 않으며 오직 앵커 기반의 거리 측정치만으로 위치를 추정할 수 있다. 제안된 방법을 검증하기 위해 건물 내에 충분하지 않은 수의 앵커를 설치하여 멀티 모달 솔루션을 발생시킨 상황에서 위치 추정 테스트를 수행하였다. 그 결과 앵커의 수가 충분치 않은 상황에서도 위치를 추정할 수 있음을 확인하였다.

• 한국항공운항학회지
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• 제21권1호
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• pp.8-14
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• 2013

As GNSS(Global Navigation Satellite System) is used in various filed, many countries establish GNSS system independently. But GNSS system has the limitation of accuracy and stability in stand-alone mode, because this system has error elements which are ionospheric delay, tropospheric delay, orbit ephemeris error, satellite clock error, and etc. For overcome of accuracy limitation, the DGPS(Differential GPS) and RTK(Real-Time Kinematic) systems are proposed. These systems perform relative positioning using the reference and user receivers. ETRI(Electronics and Telecommunications Research Institute) is developing precision navigation system in point of extension of GNSS usage. The precision navigation system is for providing the precision navigation solution to common users. If this technology is developed, GNSS system can be used in the fields which require precision positioning and control. In this paper, we introduce the precision navigation system and perform design and algorithm verification.

• Journal of Positioning, Navigation, and Timing
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• 제11권3호
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• pp.173-179
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• 2022

The satellite navigation deception technology disturbs the navigation solution of the receiver by generating a deceptive signal simulating the actual satellite for the satellite navigation receiver mounted on the unmanned aerial vehicle, which is the target of deception. A single spoofing technique that creates a single deceptive position and velocity can be divided into a synchronized spoofing signal that matches the code delay, Doppler frequency, and navigation message with the real satellite and an unsynchronized spoofing signal that does not match. In order to generate a signal synchronized with a satellite signal, a very sophisticated and high precision signal generation technology is required. In addition, the current position and speed of the UAV equipped with the receiver must be accurately detected in real time. Considering the detection accuracy of the current radar technology that detects small UAVs, it is difficult to detect UAVs with an accuracy of less than one chip. In this paper, we assume the asynchrony of a single spoofing signal and propose a region defense technique using multiple spoofing signals.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.86-90
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• 2021

The article assesses the level of navigation safety, in theoretical terms, defines the complexity of managing navigational risks in practice. The issues of assessing the navigational safety have been studied due to the importance and relevance of the issue in question, however, due to the great complexity of the problem under consideration, the article considers and indicates the directions for the development of the solution of the given direction, where, first of all, it became necessary to analyze the issue of assessing the levels of navigation risks when navigating vessels of various types in difficult navigation conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.141.5-141
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• 2001

An attitude GPS receiver with 3 antennas obtains 3-dimensional attitude using GPS carrier phase measurement INS obtains the 3 dimensional navigation solution for IMU consisting of accelerometers and gyro. Ground-alignment process for the low -cost INS cannot be performed well due to the large sensor noise. Using the standard GPS receiver, however, continuous in-flight alignment for the INS becomes possible, and consequently, the errors in IMU sensors and navigation solution can be compensated. Especially with attitude measurement from the attitude GPS receiver, the compensation of errors in gyroscope and attitude would be done respite of the vehicle´s dynamics and their error covariance would be reduced. This paper presents ...