• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.291-294
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• 2004

There are many position fixing systems in the world from ancient times. But the principles are to compare the position to want to know with the known position already. The position finding system which is not restricted by weather condition and/or electronic apparatus has been sought. The best system is the GPS as far. But the system has the fatal faults as follows; 1. to depend on satellite's accuracy, 2. not to use underwater. This paper is to investigate theoretically position fixing and north finding by using free gyroscope. This paper introduce a position fixing and north finding method by measuring inclination of 2 free gyroscopes. And this system does not depend on the weather condition and underwater condition. What is more, it could use on the planets, if the gravity exits.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.6
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• pp.63-73
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• 2008

The helicopter position, heading data and the direction finding data of ESM are essentially required to compensate the parallax and analyze the direction finding accuracy of heliborne ESM in flight test phase. In the case of the long test range compared with small platform like as LYNX helicopter and Jisim Island test site, the parallax compensation for direction finding accuracy calculation and GPS position error can be neglected. In this paper, the direction finding accuracy on the basis of helicopter propeller was calculated by coordinate changing between helicopter and transmitting antenna from WGS84 coordinate to navigation coordinate using helicopter position and direction finding data.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.83-92
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• 2018

This paper uses the Apollonius Circle technique to estimate the position of a target that generates a specific signal by using a drone, which is rapidly becoming a rapidly expanding industry. The existing direction finding method is performed through the vehicle on the ground or installed the antenna at a high position to detect the position of the target. However, the conventional direction finding method is difficult to configure the reception environment of the LOS signal, It is difficult. However, the direction finding using the drone is easy to construct and measure the LOS signal receiving environment using the drone flying at high altitude. In this study, we use the 3D 800MHz Path-Loss Model to reconstruct the signal by using the measurement data of the ground direction finding, reconstruct the signal by using the 3-D 800MHz Path-Loss Model, and use the Apollonius Circle method to estimate the position of the target. A simulation was performed to estimate the position of the target. Simulation was performed to determine the target position estimation performance by configuring the ground direction finding and the dron direction finding.

• Architectural research
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• v.14 no.4
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• pp.143-152
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• 2012

A form-finding procedure is presented for planar tensegrity structures. Notably, a simple decision criteria is proposed to select the desirable candidate position vector from the unitary matrix produced by the eigenvalue decomposition of force density matrix. The soundness of the candidate position vector guarantees faster convergence and produces a desirable form of tensegrity without any member having zero-length. Several numerical examples are provided to demonstrate the capability of the proposed form-finding process.

• Journal of the Korean Institute of Navigation
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• v.4 no.1
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• pp.1-18
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• 1980

As the NNSS system calculates ship's position by the doppler shift of the NNSS radio waves caused by the change of the distance between Transit Satellite and the ship, ship's speed error inevitably results in the position error, and moreover this kind of erroris most dominant compared with other errors especially in high speed ships and airplanes. Most NNSS receivers now in use have adoptedsuccessive short doppler counts as positioning data and by investigating the dispersion of serval successive positions calculated and by neglecting the mean position having dispersion of over certain threshold level, more accurate adn safe position is to be achieved. This paper proposes the method of finding ship's true speed by selecting a speed having least position dispersion for given successive doppler counts. And by computer simulation it was verified that the method proposed here is reasonable in finding the ship's desired correct speed together with the correct ship's position.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.373-378
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• 2014

The technology of direction finding is very important to make high position fixing accuracy. TDOA(time difference of arrival) direction finding technology is a high accuracy technology and is used in RF system from 1990. The principle of TDOA is to receive an emitter signal with two antennas, measure the time difference of received signal and then convert the time differences to azimuth angle. For high DF(direction finding) accuracy long basis line and high SNR at receiving system are needed. The DF accuracy and position fixing accuracy are simulated with different SNRs and antenna base lines. We obtain the DF accuracy of $0.51^{\circ}$ at $0^{\circ}$ incident azimuth angle in case of 50m base line and 40dB SNR.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.568-570
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• 2004

This paper presents a study of a position finding system using PSD Sensor and Pan/Tilt. The position of PSD(Position Sensitive Detector) sensor is calculated by the degree of pan-tilt and the difference in height between pan-tilt and PSD. For that, the DSP which control pan-tilt is used for precise operation. The PIC microcontroller process PSD sensor data that indicate light incident position. A user using computer can acquire the conditions of pan-tilt and PSD and issue an order.

• Architectural research
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• v.17 no.1
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• pp.31-40
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• 2015

A simple force-finding process based on an optimization technique is proposed for tensegrity structures. For this purpose, the inverse problem of form-finding process is formulated. Therefore, the position vector of nodes and element connectivity information are provided as priori. Several benchmark tests are carried out to demonstrate the performance of the present force-finding process. In particular, the force density distributions of simplex tensegrity are thoroughly investigated with the important parameters such as the radius, height and twisting angle of simplex tensegrity. Finally, the force density distribution of arch tensegrity is produced by using the present force-finding process for a future reference solution.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2665-2667
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• 2004

This paper presents a study of a position finding system for a reactor inspection robot. The position of PSD(Position Sensitive Detector) sensor is calculated by the degree of pan-tilt and the difference in height between pan-tilt and PSD. For that, the DSP which control pan-tilt is used for precise operation and the PIC microcontroller process PSD sensor data that indicate light incident position. A user using computer can acquire the conditions of pan-tilt and PSD.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.97-104
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• 2018

In the conventional direction finding, the antenna is installed at a high position on the ground to detect the position of the target with the environment of the LOS(Line of Sight) as much as the signal receiving environment. However, in order to configure such environment, high cost and installation time were required. In this paper, we use TDOA(Time Difference of Arrival) technique to utilize drones in direction finding, so that four drones can be used for directions finding simulation. Simulations based on drone and TDOA direction finding were constructed using additional signal processing Taylor series and Exact Interactive Algorithm. In the simulation, the receiving power is defined by using the 800MHz path-loss model using the GPS information of the ground direction detection, and the position estimation performance is analyzed when the TDOA technique, the Taylor series, and the Exact Interactive Alogrithm are applied.