• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.41-49
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• 2007

In this paper, we proposed a new ultrasonic distance measurement system with high accuracy and long range. To improve accuracy and enlarge range, the time of flight of ultrasonic is calculated by the period detecting method. In the proposed ultrasonic distance measurement system, the ultrasonic transmitter and receiver are separated but synchronized by RF(Radio frequency) module. The experiment has been implemented from short distance 1m to maximum available distance 30m. And the period detecting method is compared with the conventional threshold level method. Experimental results show the accuracy and range of the distance measurement are improved by this period detecting method.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.47-54
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• 2018

The purpose of this study is to verify the long - range measurement performance for practical field application of VDMS. The reliability of the VDMS was verified by comparison with the existing monitoring sensor, GPS, Accelerometer and LDS. It showed the ability to accurately measure the dynamic displacement by tracking a motion of free vibration of target. And using the PSD function of measured data, the results in the frequency domain were also analyzed. We judged that VDMS is able to identify the higher system mode and has sufficient reliability. Based on the reliability verification, we conducted tests for long-distance applicability for actual application of VDMS. The distance from the stationary target model structure was increased by 50m interval, and the maximum distance was set to 400m. From the distance of 150m, the image obtained by the commercial camcorder has an error in the analysis, so the measured displacement comparison was performed between the LDS and the refractor telescope measurement results. In the measurement results of the displacement area of VDMS, the data validity was deteriorated due to the data shift by the external force and the quality degradation of the enlarged image. However, even under the condition that the effectiveness of the displacement measurement data of VDMS is low, the first mode characteristic included in the free vibration of the object is clearly measured. If the influence from the external environment is controlled and stable data is collected, It is judged that reliability of long-distance VDMS can be secured.

• 비파괴검사학회지
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• 제25권5호
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• pp.343-349
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• 2005

광섬유 브래그 격자(fiber Bragg grating, FBC)는 1989년 Melts의 실험이후 광통신 분야 및 센서 분야에 다양한 용도를 가지고 있다. 이를 이용하여 광섬유 레이저, 대역 통과 필터로 사용하거나, 여러 가지 물리량을 측정하기 위한 온도, 변형률, 변위센서 등에 응용할 수 있다. 특히 본 연구에서는 기존 센서가 가지지 못한 긴 게이지 길이에서의 측정을 위해서 광섬유 센서 정적 시스템(FBG Static Logger)과 FBG 센서가 포함된 긴 길이의 광섬유를 이용하여 장대 구조물의 변형이나 외부 reference의 상대변위를 길게 연결하여 측정하기 쉽지 않은 변위를 측정하여 구조물의 상황을 상시 점검하고 더 나아가 잔존수명을 예측하고 보수시기를 알려줄 수 있는 방법을 모색하여 FBG. 센서의 패키지(package)를 고안하였다. 이를 통해 효율적인 장거리 변위 측정방법을 정립하고 이를 원자력 격납구조물에 적용하여 성공적으로 측정함으로써 광섬유 격자센서를 이용하여 50m 이상의 장거리 계측의 가능성을 보여 주었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.291-291
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• 2002

DGPS(Differential Global Positioning System) and RTK(RealTime Kinematic) is in one of today's most widely used surveying techniques. But It's use is restricted by the distance between reference station and rover station and it is difficult to process data in realtime by it's own orgnizational limitation in precise measurement of positioning. To meet these new demands, In This paper, new DGPS and RTK correction data services through Internet and PSTN(Public Switched Telephony Network) have been proposed. For this purpose, we implemented performance a DGPS and RTK error correction data transmission system for long-distance using the internet and PSTN network which allows a mobile user to increase the distance at which the rover receiver is located from the reference in realtime. and we analyzed and compared DGPS and RTK performance by experiments through the Internet and PSTN network with the distance and the time.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.396-400
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• 2012

We introduce a combined technique and the mathematical description for distance measurements using a femtosecond pulse laser in a long range and a fine resolution. For distance measurements, the maximum measurable range can be extended by combining measurement results from several different methods while requiring relationships between the different measurement uncertainties and unambiguity ranges. This paper briefly explains why the uncertainty of a rough measurement technique (RMT) should be, at least, smaller than the half unambiguity range of a fine measurement technique (FMT) in order to combine a FMT with a RMT. Further discussions about the total measurement range, resolution, and uncertainty for various optical measurement techniques are also discussed.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.231-234
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• 2007

A measurement technique in an industry site is basis technique which is bringing a ripple effect on an increasing productivity. Recently, a measurement request is increasing in the industry field as well as the variety field such as leisure, research. Thus, it is in point of time to secure an internal technique about measurement using a laser. In this paper, we prepare to develop the industrial precision laser distance measure device that is available measuring in several hundred meters[m]. In other words, we are planning to measure a wide distance using a laser diode that has long life and is compact, inexpensive. Through this research, we'll secure the pulse laser control technique, a signal processing, technique for distance calculation about a laser distance measurement system. And hereafter, we'll plan to commercialize a laser distance device using this research.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.319-327
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• 2016

Purpose: Automated guidance systems (AGSs) for mobile farm machinery have several advantages over manual operation in the crop production industry. Many researchers and companies have tried to develop such a system. However, it is not easy to evaluate the performance of an AGS because there is no established device used to evaluate it that complies with the ISO 12188 standard. The objective of this study was to develop a tracking sensor system using five laser distance measurement sensors. Methods: One sensor-for long-range distance measurement-was used to measure travel distance and velocity. The other four sensors-for mid-range distance measurement-were used to measure lateral deviation. Stationary, manual driving, and A-B line tests were conducted, and the results were compared with the real-time kinematic differential global positioning system (RTK-DGPS) signal used by the AGS. Results: For the stationary test, the average error of the tracking sensor system was 1.99 mm, and the average error of the RTK-DGPS was 15.19 mm. For the two types of driving tests, the data trends were similar. A comparison of the changes in lateral deviation showed that the data stability of the developed tracking system was better. Conclusions: Although the tracking system was not capable of measuring long travel distances under strong sunlight illumination because of the long-range sensor's limitations, this dilemma could be overcome using a higher-performance sensor.

• 한국안광학회지
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• 제18권4호
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• pp.495-501
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• 2013

목적: 본 연구는 망원경과 바이프리즘(biprism)을 이용하여 골퍼로부터 깃대까지의 거리를 정확히 측정할 수 있는 골프 거리측정기를 개발하기 위한 것이다. 방법: 망원경내부에 이동 가능한 바이프리즘을 포함시켜 골프거리측정기를 제작하였으며. 20~200 m 거리에서 제작된 거리측정기의 정확도를 분석하였다. 결과: 바이프리즘의 위치에 따라 거리를 계산할 수 있는 방정식을 유도하였으며 개발된 골프거리측정기를 이용하여 성공적으로 거리를 측정할 수 있었다. 2 ${\Delta}$의 바이프리즘이 짧은 거리의 측정에서는 유용했지만 먼 거리의 측정에서는 정확도가 떨어지는 것으로 나타났으며 먼 거리의 측정에는 0.5 ${\Delta}$이 더 유용한 것으로 나타났다. 먼 거리를 측정하기 위하여 바이프리즘이 대물렌즈의 초점부근으로 접근할 때 상이 나빠지는 현상이 나타났으며, 이러한 약점을 보완하기 위하여 다층형 바이프리즘을 개발하였다. 결론: 바이프리즘을 이용하여 손떨림에 구애받지 않고 거리를 잘 측정할 수 있었으며 유도한 거리계산 방정식이 유용함을 확인하였다. 먼 거리를 측정하기 위하여 바이프리즘이 대물렌즈의 초점부근으로 접근했을 때 새로이 고안된 다층형 바이프리즘이 일반적인 바이프리즘보다 유용하다는 것을 확인하였다.

• 센서학회지
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• 제22권6호
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• pp.387-392
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• 2013

Camera rigs for shooting 3D video are classified as manual, motorized, or fully automatic. Even in an automatic camera rig, the process of Stereoscopic 3D (S3D) video capture is very complex and time-consuming. One of the key time-consuming operations is capturing the distance parameters, which are near distance, far distance, and convergence distance. Traditionally these distances are measured by tape measure or triangular indirect measurement methods. These two methods consume a long time for every scene in shot. In our study, a compact laser distance sensing system with long range distance sensitivity is developed. The system is small enough to be installed on top of a camera and the measuring accuracy is within 2% even at a range of 50 m. The shooting time of an automatic camera rig equipped with the laser distance sensing system can be reduced significantly to less than a minute.

• 한국전자파학회논문지
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• 제22권2호
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• pp.182-190
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• 2011

진폭 변조를 이용한 거리 측정 시스템은 반송파를 진폭 변조하여 송수신한 신호의 진폭 변조 신호의 위상차를 사용하여 거리를 측정하게 된다. 진폭 변조 거리 측정 시스템에서 문제가 되는 안테나 간의 누설 신호 및 불요 신호에 의한 측정 오차를 최소화하기 위해 능동반사기를 사용하여 주파수 대역을 바꾸어 송신하는 방식이 제안되었다. 본 논문에서는 모호성이 없는 측정 거리를 확장하면서도 정밀한 측정을 가능하게 하는 새로운 위상측정부의 구현에 대해 설명하고 있다. 즉, 8 MHz 및 1 MHz의 두 개의 변조 주파수를 교차적으로 선택하여 변조함으로써, 150 m까지의 거리를 2 cm 이하의 오차로서 측정할 수 있게 하였다. 위상측정부는 정밀한 위상 측정을 위하여 높은 변조 주파수는 JK 플립플롭 위상차 측정기를 사용하고, 낮은 변조 주파수일 경우는 XOR 위상차 측정기를 사용하였다.