Gyu-In Jee is an full Professor in the Department of Electronics Engineering at Konkuk University in Seoul, Korea. He received his Ph.D. in Systems Engineering from Case Western Reserve University. He has worked on several GPS related research projects; GPS receiver software design, GPS/INS integration for land vehicle, DGPS system development, GPS engine design using the Mitel chip sets, wirel...

We present interference analysis from Non-communication device which is used in many applications such as factory, home and hospital into Global Positioning System (GPS) Service. GPS service is used to detect location for car driving and safety of life. Nowadays, non-communication devices are increased rapidly. Therefore, in case that noncommunication device and GPS receiver are operated in clo...

This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage ...

OBJECTIVE To determine how the timing and length of hospital discharge letters impact on the number of ongoing patient problems identified by general practitioners (GPs). TRIAL DESIGN GPs were randomised into four groups. Each viewed a video monologue of an actor-patient as he might present to his GP following a hospital admission with 10 problems. GPs were provided with a medical record as w...

Route taken and distance travelled are important parameters for studies of animal locomotion. They are often measured using a collar equipped with GPS. Collar weight restrictions limit battery size, which leads to a compromise between collar operating life and GPS fix rate. In studies that rely on linear interpolation between intermittent GPS fixes, path tortuosity will often lead to inaccurate...

GPS seismology uses convential geodetic models to analyze GPS data at high sampling rates, such as 1 Hz. GPS seismology results are shown for the Denali, San Simeon, Tokachi-oki, and Chuetsu earthquakes. Records for these earthquakes indicate that GPS is an excellent instrument for measuring large displacements near earthquake ruptures. GPS systems can be improved for seismic applications if th...

The aviation industry’s increasing reliance on GPS to facilitate navigation and air traffic monitoring opens new attack vectors with the purpose of hijacking UAVs or interfering with air safety. We propose Crowd-GPS-Sec to detect and localize GPS spoofing attacks on moving airborne targets such as UAVs or commercial airliners. Unlike previous attempts to secure GPS, Crowd-GPS-Sec neither requir...

BACKGROUND Given the importance of community-based research, there is a need to ensure the quality of data obtained from such studies. However, research has been considered a low priority for most GPs. OBJECTIVES To assess the quality of data reported by GPs in a large community-based study. METHODS Men were recruited as part of a population-based study on prostate-specific antigen (PSA) te...

OBJECTIVE To evaluate a hospital-based psychiatric consultation service for patients referred by general practitioners (GPs), and the effect on its use of a focused marketing strategy aimed at GPs. DESIGN AND SETTING Postal survey of GPs in the catchment area (inner north Brisbane, Queensland), September to November 2003; and assessment of referrals, March to August 2003. MAIN OUTCOME MEASU...

Carrier phase based DGPS systems have been used for airborne mapping for many years. Integrated GPS/INS systems are also becoming popular in order to improve the positioning accuracy, system reliability and achieve direct geo-referencing. However, this approach is limited by the current GPS constellation. Further improvement is required to achieve centimetre level positioning accuracy, which be...