• Journal of the Korea Society of Computer and Information
• /
• v.27 no.8
• /
• pp.77-84
• /
• 2022

In this paper, we propose a system for monitoring air pollutants such as fine dust using an unmanned aerial vehicle capable of autonomous navigation. The existing air quality management system used a method of collecting information through a fixed sensor box or through a measurement sensor of a drone using a control device. This has disadvantages in that additional procedures for data collection and transmission must be performed in a limited space and for monitoring. In this paper, to overcome this problem, a GPS module for location information and a PMS7003 module for fine dust measurement are embedded in an unmanned aerial vehicle capable of autonomous navigation through flight information designation, and the collected information is stored in the SD module, and after the flight is completed, press the transmit button. It configures a system of one-stop structure that is stored in a remote database through a smartphone app connected via Bluetooth. In addition, an HTML5-based web monitoring page for real-time monitoring is configured and provided to interested users. The results of this study can be utilized in an environmental monitoring system through an unmanned aerial vehicle, and in the future, various pollutants measuring sensors such as sulfur dioxide and carbon dioxide will be added to develop it into a total environmental control system.

• Journal of the Korean Geophysical Society
• /
• v.9 no.4
• /
• pp.361-369
• /
• 2006

This study conducted an initialization test to decide dynamic position using AHRS IMU sensor, and derived attitude correction angles of vehicles against time through regression analysis. It was also found that the heading angle was stabilized with variation less than 1°after 60 seconds. Using these angles, this study carried out an experiment on the determination of dynamic position for each system in the open sky and in a semi-open sky. According to the results, in the open sky, DGPS alone systems were excellent in accuracy but poor in data acquisition, so the moving distance was around 12m. In DGPS/IMU combined system, accuracy and data acquisition were satisfactory and the moving distance was around 0.3m. In a semi-open sky, DGPS alone systems were excellent in accuracy in order of DGPS < FIMU < DGPS/IMU according to average and standard errors obtained with exclusion of places where data were not be obtained. The moving distance was the same as that in the open sky. For DGPS, when places where data were not obtainable were divided into Several block and they were compared, the maximum deviation from the trajectory was up to 41.5m in DGPS alone system, but it was less than 2.2m and average and standard errors were significantly improved in the combined system. When the navigation system was applied to surveys and the result was compared with position error 0.2mm under the guideline for digital map, it was possible to work on maps on a scale of up to 1 : 1,000.

• Journal of Navigation and Port Research
• /
• v.35 no.8
• /
• pp.625-629
• /
• 2011

In this study, we analyzed the signal environment of 17 DGNSS stations operated by DGPS Central Office through TEQC quality checking, visibility analysis and site visits. With TEQC, we produced times series of four indices of TEQC quality checking: observation ratio, L1 pseudorange multipath, L2 pseudorange multipath, and the frequency of cycle slip events. From visibility analysis, the directions where missing observations are happening were identified and the result was verified through onsite investigation. Without considering TEQC indices at the six sites(Palmido, Eochungdo, Geomundo, Pyeongchang, Seongju, and Chungju), the average TEQC indices were: 98% observation ratio, 0.19m of L1 pseudorange multipath, 0.71m of L2 pseudorange multipath, and 1.3 cycle slips per 1000 observations. The observation ratios at Palmido and Eochungdo were low. It was found that receiver settings were incorrect so that they could track the P2 signal of GPS satellites with L2C capability. No signal-blocking obstacles were found around the Geomundo station except the lighthouse. Thus, we guess that the poor TEQC indices at the site are believed to be caused by problems in the GPS hardware or cables. The low observation ratio at Pyeongchang is being caused by the surrounding hills blocking the satellite view from the south to the northwest directions. Even though all of four TEQC indices were bad at Seongju and Chungju stations, we found that the signal reception environment at the two sites is in good condition. We think that the quality indices got poor probably because of malfunctioning equipment. So, further investigation is needed for the Seongju and Chungju sites.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2003.05a
• /
• pp.181-186
• /
• 2003

The satellite navigation system is widely used for identifying a user's position regardless of weather or geographic conditions and also make effect on new technology of marine LBS(Location Based Service), which has the technology of geographic information such as the ENC. Generally, there are conceivable systems of marine LBS such as ECDIS, or ECS that use the ENC itself with powerful processor in installed type on ships bridge. Since the ENC is relatively heavy structure with dummy format for data transfer between different systems, we should reduce the ENC to small and compact size in order to use it in mobile platform. In this paper, we assumed that the mobile system like PDA, or Webpad can be used for small capability of mobile platform. However, the ENC should be updated periodically by update profile data produced by HO. If we would reduce the ENC without a consideration of update, we could not get newly updated data furthermore. As summary, we studied considerations for ENC reduction with update capability. It will make the ENC be useful in many mobile platforms for various applications.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_1
• /
• pp.1125-1139
• /
• 2022

In an unmanned aerial vehicles (UAVs) system, a physical offset can be existed between the global positioning system/inertial measurement unit (GPS/IMU) sensor and the observation sensor such as a hyperspectral sensor, and a lidar sensor. As a result of the physical offset, a misalignment between each image can be occurred along with a flight direction. In particular, in a case of multi-sensor system, an observation sensor has to be replaced regularly to equip another observation sensor, and then, a high cost should be paid to acquire a calibration parameter. In this study, we establish a precise sensor model equation to apply for a multiple sensor in common and propose an independent physical offset estimation method. The proposed method consists of 3 steps. Firstly, we define an appropriate rotation matrix for our system, and an initial sensor model equation for direct-georeferencing. Next, an observation equation for the physical offset estimation is established by extracting a corresponding point between a ground control point and the observed data from a sensor. Finally, the physical offset is estimated based on the observed data, and the precise sensor model equation is established by applying the estimated parameters to the initial sensor model equation. 4 region's datasets(Jeon-ju, Incheon, Alaska, Norway) with a different latitude, longitude were compared to analyze the effects of the calibration parameter. We confirmed that a misalignment between images were adjusted after applying for the physical offset in the sensor model equation. An absolute position accuracy was analyzed in the Incheon dataset, compared to a ground control point. For the hyperspectral image, root mean square error (RMSE) for X, Y direction was calculated for 0.12 m, and for the point cloud, RMSE was calculated for 0.03 m. Furthermore, a relative position accuracy for a specific point between the adjusted point cloud and the hyperspectral images were also analyzed for 0.07 m, so we confirmed that a precise data mapping is available for an observation without a ground control point through the proposed estimation method, and we also confirmed a possibility of multi-sensor fusion. From this study, we expect that a flexible multi-sensor platform system can be operated through the independent parameter estimation method with an economic cost saving.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.1
• /
• pp.70-78
• /
• 2013

Before GBAS ground systems is installed at the airport, the site survey is needed to determine the suitability of proposed GBAS candidate sites depending on the siting requirements. Therefore, analysis of GPS signal reception environment, one of the site survey steps, is required. In this paper, the number of visible satellites, GPS signal strength, multipath error, radio frequency interference and predicted availability were analyzed using the GPS data of Gimpo International Airport measured by PortaSAT equipments and the analysis results were represented.

• Journal of Advanced Navigation Technology
• /
• v.14 no.3
• /
• pp.297-302
• /
• 2010

The AtoN is subsidiary navigation facilities for ship to navigate safely. AtoN includes signs of visual, sound, special and radio. Receltly as GNSS and AIS are developed rapidly, AtoN has been considered as a promising candidate technique for ensuring fairway safety of ship. However, present AtoN systems are not adopted to ship fully, but are adopted to ship partly, and total management systems are not installed. In this study, AtoN Monitoring system based on AIS is developed. It consists of AIS system and AIS viewer program. In the system AIS gathers data of AtoN and ship information and AIS viewer is a program that plots AIS data on ECDIS.

• Journal of Digital Convergence
• /
• v.18 no.6
• /
• pp.495-500
• /
• 2020

This study was intended to quantify the acceleration and deceleration information measured in the competition by using GPS device for the national women's field hockey players and to identify the difference in movement by classifying them by position. For this study, 308 acceleration and deceleration data were collected from 16 women's field hockey players measured at international competitions. According to research results, the frequency of acceleration was in the order of midfield > defender > striker, acceleration distance was midfield > striker > defender. The frequency of deceleration appeared in the order of midfield > defender > striker, deceleration distance was defender > striker > defender. Based on the results of this study, can be used as basic data when setting the strength and amount of training for field hockey players.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.2
• /
• pp.302-313
• /
• 2018

As the demand for indoor location recognition system has been rapidly increased in accordance with the increasing use of smart devices and the increasing use of augmented reality, indoor positioning systems(IPS) using BLE (Bluetooth Lower Energy) beacons and UWB (Ultra Wide Band) have been developed. In this paper, a positioning plate is generated by using trilateration technique based on BLE Beacon and using RSSI (Received Signal Strength Indicator). The resultant value is used to calculate the PDR-based coordinates using the positioning element of the Inertial Measurement Unit sensor, We propose a precise indoor positioning algorithm that combines RSSI and PDR technique. Based on the plate algorithm proposed in this paper, the experiment have done at large scale indoor sports arena and airport, and the results were successfully verified by 65% accuracy improvement with average 2.2m error.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.10
• /
• pp.946-951
• /
• 2011

This paper presents the simulation results of GBAS availability and requirement (with respected to Vertical Protection Level) using simulated data at CAT I, CAT II/III DH point (Decision Height), which are generated using Jeju international GNSS reference position, aircraft horizontal velocity and reference/aircraft GNSS antenna performance index and so on. Two kinds of protection levels are presented, one is from a hypothesis (H0) and other is from a alternative hypothesis (H1). These protection levels are compared with AL (Alert Limit), and we analyse the GBAS availability and requirement for CAT I and CAT II/III at the airport.