• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.127-136
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• 2002

This paper Presents a discussion on the design and realization for the Phase Sensitive Defector (PSD) circuitry of Flu$\chi$-gate Compass that gives direction information to the Directional Frequency Analysis and Recording (DIFAR) Sonobuoy in Air Anti-Submarine Warfare. PSD circuitry is realized with Twin-T RC networked active band-pass filter. Results of a performance test the PSD circuitry shows that the effectiveness of band-pass filtering of desired $2F_0$ second harmonic signal, which is Pro- portional to the direction of earth's magnetic field. This resulted in the extraction of direction information.

• Transactions on Electrical and Electronic Materials
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• v.6 no.3
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• pp.110-114
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• 2005

We present a micro fluxgate magnetic sensor having solenoid coils and racetrack shaped magnetic core, which was designed to decrease the .operating power and magnetic flux leakage. Electroplated copper coils of $6\;{\mu}m$ thickness and the core of $3\;{\mu}m$ thickness were separated by benzocyclobutane (BCB) having a high insulation and good planarization characters. Permalloy $(Ni_{0.8}Fe_{0.2})$ as a magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The core had the high DC effective permeability of $\~1,300$ and coercive field of $\~0.1$ Oe. The fabricated fluxgate sensor had the very small actual size of $3.0\times1.7\;mm^2$. The fluxgate sensor with a racetrack shaped core had the high sensitivity .of $\~350$ V/T at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1986-1991
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• 2007

In this paper, we discussed, intelligent soft filter for MR(magnetoresistive) sensor. Most navigation systems today use some type of compass to determine heading direction. Using the earth's magnetic field, electronic compass based on MR(magnetoresistive) sensors can electrically resolve better then 0.1 degree rotation. Intelligent methode for soft building a one degree compass using MR(magnetoresistive) sensors will also be discussed. Compensation techniques are shown to correct for compass tilt angels and nearby ferrous material disturbances. we proved the fuzzy logic that based on the way the ham deals with inexact information is useful for MR sensors.

• Journal of Navigation and Port Research
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• v.41 no.4
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• pp.189-194
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• 2017

The Moving Search Radar System (MSRS) monitors sea areas by moving along the coast. Since the radar is initially aligned to the front of the vehicle, it is important to know the changes in the heading azimuth of the vehicle to quickly acquire the target azimuth from the radar after the MSRS has moved. The heading azimuth can be obtained using the gyro compass, the GPS compass or the electronic compass. The electronic compass is suitable for MSRS requiring fast maneuverability due to its small volume, short stabilization time and low price. However, using a geomagnetic sensor may result in an error due to the surrounding magnetic field. Errors can make early automatic tracking of the satellites difficult and can reduce the radar detection accuracy. Therefore, this paper proposes a method to automatically compensate for the error reflecting the correction value on the radar obtained by comparing the reference azimuth calculated by solving the geodesic inverse problem using two coordinates between the radar and the geostationary satellite with the actually-directed azimuth angle of the satellite antenna. The feasibility and convenience of the proposed method were verified by applying it to the MSRS in the field.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1057-1064
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• 2017

High sensitivity magnetic sensor having foreign metal detection capability is proposed utilizing giant magneto-impedance effect. Strip sensor showed the increasing output voltage when the external magnetic field was applied along with strip from strip grounding point, although the initial DC voltage varied depending on the pointing direction of strip sensor. Proposed sensor was able to eliminate more than half of background noise using active noise filter to achive high sensitivity, and it showed the capability to detect magnetized foreign metal object independent of ambient electro-magnetic noise and earth magnet. In case of ferrous sphere, the metal detection up to 0.8mm diameter was experimentally demonstrated at 5mm distance from strip sensor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.508-514
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• 2004

A fluxgate magnetic sensor consists of a solenoid excitation coil, pick-up coil, and magnetic core. We presents the effect of magnetic core shape in a micromachined fluxgate sensor. To observe the performance of fluxgate sensor with magnetic core side width and gap, side width of 125 ${\mu}{\textrm}{m}$, 250 ${\mu}{\textrm}{m}$, and 500 ${\mu}{\textrm}{m}$ were designed in a rectangular-ring shaped core and the gaps of 0 ${\mu}{\textrm}{m}$, 50 ${\mu}{\textrm}{m}$, and 100 ${\mu}{\textrm}{m}$ were also fabricated in a racetrack shaped core. The solenoid coils and magnetic core were separated by benzocyclobutane(BCB) which had high insulation and good planarization characters. Copper coil patterns of 10 ${\mu}{\textrm}{m}$ width and 6${\mu}{\textrm}{m}$ thickness were electroplated on Ti(300 $\AA$) / Cu(1500 $\AA$) seed layers. 3 ${\mu}{\textrm}{m}$ thick N $i_{0.8}$F $e_{0.2.}$(permalloy) film for the magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The magnetic core had the high DC effective permeability of ∼1,300 and coercive field of ∼0.1 Oe. Because the magnetic cores of 500 ${\mu}{\textrm}{m}$ side width and 0 gap had a low magnetic flux leakage, high sensitivity of ∼350 V/T were measured at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. The power consumption of ∼14 ㎽ was measured. The fabricated fluxgate sensor had the very small actual size of 3.0${\times}$1.7 $\textrm{mm}^2$. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.m.m.m.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.80-80
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• 2000

The GPS can provide accurate position information on the earth. But GPS receiver can't give position information inside buildings. DR(Dead-Reckoning) or INS(Inertial Navigation System) gives position information continuously indoors as well as outdoors, because they do not depend on the external navigation information. But in general, the inertial sensors severely suffer from their drift errors, the error of these navigation system increases with time. GPS and DR sensors can be integrated together with Kalman filter to overcome these problems. In this paper, we developed a personal navigation system which can be carried by person, using GPS and electronic pedometer. The person's footstep is detected by an accelerometer installed in vertical direction and the direction of movement is sensed by gyroscope and magnetic compass. In this case the step size is varying with person and changing with circumstance, so determining step size is the problem. In order to calculate the step size of detected footstep, the neural network method is used. The teaming pattern of the neural network is determined by human walking pattern data provided by 3-axis accelerometer and gyroscope. We can calculate person's location with displacement and heading from this information. And this neural network method that calculates step size gives more improved position information better than fixed step size.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.375-378
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• 2007

This paper describes indoor location estimation intelligent robot. It is loaded indoor location estimation function using RSSI based indoor location estimation system and wireless sensor networks. Spartan III(Xilinx, U.S.A.) is used as a main control device in the mobile robot and the current direction data is collected in the indoor location estimation system. The data is transferred to the wireless sensor network node attached to the mobile robot through Zigbee/IEEE 802.15.4, a wireless communication. After receiving it, with the data of magnetic compass the node is aware of and senses the direction the robot head for and the robot moves to its destination. Indoor location estimation intelligent robot is can be moved efficiently and actively without obstacle on flat ground to the appointment position by user.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.137-149
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• 1994

This study was performed to investigate the relationship between Forward Head Posture(FHP) and Craniomandlbular Disorders(CMDs). Many studies reported that there was some relationship between them, however, there is still controversy. So It Is necessary to observe and compare many more patients with CMDs wirh normal controls. For the study 85 patients with CMDs and 37 dental students were selected as experimentals and controls, respectively. And the experimentals were classified Into two groups, that is, TMJ internal derangement group and muscle disorders group according to clinical diagnosis. For measuring the FHP, CROM(Cervical-Range-of-Notion)was used. This goniometer is composed of three part. First, gravity goniometer for flexion and extension. Second, magnetic compass and yoke for rotational movement. And last, forward head arm and vertebra locator for forward head posture. Next T-Scan, electronic occlusal analyzer, was used for recording of occlusal contact state. Other items such as maximum opening, lateral excursion, Helkimo's anamnestic index, and muscle palpation point from Friction's craniomandibular index were checked clinically by one examiner. The result of this study were as follows : 1. In male, control group showed much more measurement in resting forward head posture than did experimental group. But there were not significant differences between groups in female subject. From this results, the author contended that CROM is new measuring system and differ from other goniometers in some aspect, so that results should be re-evaluated 2. Mean value of maximum mouth opening in nearly all groups were greater than 40mm. and mouth opening had a significant correlation with occlusal force and with anamnestic index both sex. 3. Mean value of palpation point had not any correlationship with forward head posture in both sex, but there was significant difference between upper and lower group by rounded shouldes. 4. In summary, there was no significant relationship between forward head posture and sign and symptom of Craniomandibular Disorders.