We study the problem of accurately determining the position of a mobile device using imprecise off-the-shelf GPS devices. Existing work has not yet explored the impact of mobility on GPS error for off-the-shelf devices. We demonstrate that a naive use of GPS in mobile situations can lead to significant errors. Based on both stationary and mobile vehicular experiments, we identify four distinct ...

An innovative orbit determination method which makes use of gravity gradients for Low-Earth-Orbiting satellites is proposed. The measurement principle of gravity gradiometry is briefly reviewed and the sources of measurement error are analyzed. An adaptive hybrid least squares batch filter based on linearization of the orbital equation and unscented transformation of the measurement equation is...

In this paper, a novel GPS (Global Positioning System) and DR (Dead Reckoning) system which was based on the accelerometer and gyroscope integrated system was designed and implemented. In this system, the odometer used in traditional DR system was replaced by a MEMS tri-axis accelerometer in order to decrease the cost and the volume of the system. The system was integrated by the Kalman filter ...

The performances of several GPS L5 tracking implementations are evaluated using IF samples obtained with a hardware simulator. The aim of this study is to determine the loop structure and parameters that are most suited to accommodate the various design innovations, such as the data/pilot implementation or spreading sequence definition, inherent to the GPS L5 signal. In particular, the Kalman f...

BACKGROUND Our research is based on a technique for time sampling, an innovative method for measuring the working hours of Dutch general practitioners (GPs), which was deployed in an earlier study. In this study, 1051 GPs were questioned about their activities in real time by sending them one SMS text message every 3 h during 1 week. The required sample size for this study is important for heal...

A hybrid positioning system is merely one in which multiple systems are used for positioning purposes. This virtually always, though not necessarily, includes Global Positioning System (GPS) as it is the only global positioning network currently. Combination of mobile network and GPS positioning techniques provide a higher accuracy of mobile location than positions based on a standalone GPS or ...

N O V E M B E R / D E C E M B E R 2 0 1 4 www.insidegnss.com Efficient power transmission and distribution would benefit from synchronized near–real-time measurements of voltage and current phasors at widely dispersed locations in an electric power grid. Such measurements also could enable effective realtime system monitoring and control, which are considered to be the key to preventing wide-sc...

GPS instrumentation capable of measuring a missile intercept event with less than 2-centimeter accuracy has been demonstrated in a special high speed/acceleration sled test at Holloman AFB. Although the basic instrumentation technique is well defined, plans to properly exploit this capability are yet to be adequately addressed. This paper reviews the demonstrated differential GPS instrumentatio...

A GPS system was designed to carry out so-called ‘tide-independent’ bathymetric measurement, in order to compare with the conventional technique in which the tidal observations are made at tide gauges along the coast. Through the estimation and introduction of attitude parameters and height corrections, both based on the GPS solutions, the tide-independent bathymetric measurement can be impleme...