• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.603-610
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• 2015

This paper presents a multimodal sensor system that can determine the location of house space by analyzing the postures and heights of the residents. It consists of two sensors: a tilt sensor and an altimeter sensor. The tilt sensor measures the static and dynamic postures of the residents, and the altimeter sensor measures their heights. The sensor system includes a Bluetooth transmitter, and the server receives the measured data and determines the location in the house. We describe the process determining the locations of the residents after analyzing their postures and behaviors from the measured data. We also demonstrate the usefulness of the proposed system by applying it to a real environment.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.749-756
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• 2013

This paper presents an algorithm concerning the ground altitude measurement using a laser altimeter and an ultrasonic rangefinder for UAV(Unmanned Aerial Vehicle). A simple ground test conducted using the laser altimeter and ultrasonic rangefinder that are used for conducting the low altitude measurement of UAV and identify the characteristics of each sensor. Especially, the disadvantages of the laser altimeter were checked through the ground test. After that who those are participated in this paper planned the algorithm which is complemented by the ultrasonic rangefinder and the experiment was conducted. The laser altimeter and the ultrasonic rangefinder were fused by a loosely coupled method by Kalman filter. The paper shows that stable value of altitude complemented by the ultrasonic rangefinder that covers the laser altimeter's drawbacks can be measured through the ground test.

• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.21-26
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• 2015

A wireless sensor network (WSN) is designed and implemented for a freeze dryer. Freeze-drying technology is widely used in the fields of pharmacy and biotechnology as well as the food and agriculture industries. Taking into account the demand for high-resolution pressure and temperature measurements in a freeze dryer, the proposed WSN has a significant advantage of creating a monitoring environment in a freeze dryer. The proposed WSN uses a ZigBee/IEEE 802.15.4 network with an altimeter module that contains a high-resolution pressure and temperature sensor with a serial digital data interface. The ZigBee network is suitable for low-energy and low-data-rate applications in the field of wireless communication. The altimeter module is capable of sensing pressure in the range of 7.5-975 Torr (10-1300 mbar) and temperature in the range of $-40^{\circ}C$ to $125^{\circ}C$ with a DC power consumption of $3{\mu}W$. The implemented WSN is installed in a commercial laboratory freeze dryer in order to demonstrate its functionality and efficiency. A comparison with the temperature profile measured by a thermocouple installed in the freeze dryer reveals that the resolution of the temperature profile measured by WSN is superior to that measured by the thermocouple.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.633-633
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• 2002

We investigated the distributions of sea ice using various microwave remote sensing techniques in the part of Drake passage, Antarctica, between the area 45-75$^{\circ}$W and 55-66$^{\circ}$S. We used Topex/Poseidon(T/P) radar altimeter, ERS-1 altimeter, ERS-2 scatterometer, Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR), and DMSP Special Sensor Microwave/Imager(SSM/I) data. The sea ice distributions were estimated between May and Jun., 1995 and Oct. and Nov., 1998. The two altimeter measurements (T/P and ERS-1) showed good coherence with the results from the radiometer data in the given period when the ice concentration of 20% and greater was selected. The scatterometer data also showed good correlation with altimetry-implied sea ice surface. The maximum and minimum values of sea ice distribution were appeared in Aug. and Feb., respectively. In general, the sea ice distributions estimated from radar altimeter, radioneter, and scatterometer are well correlated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.54-60
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• 2013

This paper presents a ground altitude determination algorithm using a laser altimeter and GPS for automatic take-off and landing of UAV. The characteristics of the laser altimeter was analyzed in ground tests and a low-pass filter was designed to reduce the effect of signal interruption due to reflectivity problem. The paper shows that a single sensor cannot measure ground altitude appropriately in terms of reliability and accuracy. To complement shortcomings of the laser altimeter, the linear Kalman filter was designed using DGPS vertical speed. Designed filter was validated and tuned through the steps of simulation, ground test and flight test. It was confirmed that the accuracy for automatic landing is achievable.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.4
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• pp.387-395
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• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1202-1208
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• 2008

This paper represents the multiple sensor fusion algorithm for the deep-sea unmanned underwater vehicles (UUV), composed of a remotely operated vehicle (ROV) 'Hemire' and a depressor 'Henuvy'. The performance of underwater positioning system usually highly depend on that of acoustic sensors such as ultra short base line(USBL), long base line(LBL) and altimeter. A practical sensor fusion algorithm is proposed in the sense of a moving window concept. The performance of the proposed algorithm can be observed by applying the algorithm to the Hemire sea trial data which was measured at the East Sea.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.73-78
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• 2007

The process and results of Captive Flight Test(CFT), conducted by Agency for Defense Development(ADD) using the Korean KTX-1 trainer and external fuel tank, are presented. Through over 150 sorties of CFT, the guided weapon system's critical subsystems like Seeker, Navigation Device and Technology, Inertial Sensor, and Radio Altimeter are tested and evaluated. Using the CFT, time and cost are saved in weapon system research and development procedure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.133-140
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• 2002

In this paper, the structure of integrated navigation computer for experiment is proposed. It is designed for considering the real time processing and data storage capacity. It will be used in missile, aircraft, submarine system and experimental vehicle. The I/O device supports IMU, GPS, odometer, altimeter, depth sensor, inclinometer etc. And the main storage device uses the tape device. That can improve the system stability. Therefore it can be used in a high dynamic or shock environment. The embedded linux is used as an Operating System. For the real time capability, sensor data processing and algorithm processing units are seperated. The time synchronization is referenced by IMU data.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.448-453
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• 2002

Remote sensing technology is one of the most powerful tools for human to know the nature and their living environment. However, before microwave remote sensing was developed and applied, remote sensing application was limited strongly by weather and time. Microwave remote sensing technology solves the problem. It makes us to have the capability to acquire information at all time of the day and under all weather condition, and make remote sensing technology be used in more wider area. Microwave remote sensing system include mainly Synthetic Aperture Radar (SAR), Microwave Radiometer, Microwave Scatterometer, and Altimeter (ALT). As SAR can acquire image whose spatial resolution is similar with visible and infrared image, it is paying much attention to and playing a more and more important role in earth observation. In recent year, the development of new SAR technology (multi-band and multi-polarization technology, InSAR technology, D-InSAR technology, and so on) makes SAR remote sensing go to an new stage, and its application area become more and more widely. The first Synthetic Aperture Radar (SAR) in the world appeared in 1960. After that, SAR and its application all developed very fast. Some radar satellites launched and run (include Seasat-A in 1978, ERS-1 in 1991, JERS-1 in 1992, Radarsat in 1995, and so on) promote SAR research and application in world greatly. China began to develop its SAR sensor and research SAR application in 1970s. After more than 30 years' research, it get some important development in sensor development data processing method, and application. Some operational systems have been used and play an important role. This paper will introduce the development of SAR technology and its application in China.