Global Positioning System (GPS) is proven to be an accurate positioning sensor. However, there are several sources of errors such as ionosphere and troposphere effects, satellite time errors, errors of orbit data, receivers errors, and errors resulting from multi-path effect which reduce the accuracy of low-cost GPS receivers. These sources of errors also limit the use of single-frequency GPS r...

This paper presents an accurate Differential Global Positioning System (DGPS) using multi-layered Neural Networks (NNs) based on the Back Propagation (BP) and Imperialistic Competition Algorithm (ICA) in order to predict the DGPS corrections for accurate positioning. Simulation results allowed us to optimize the NN performance in term of residual mean square error. We compare results obtained b...

This paper describes new Differential and RTK GPS/GLONASS correction service through the Internet. The DGPS correction services that are available in Japan at present can not satisfy all potential users. Most of their limitations related to the fact that they use radio broadcast for their service. We will provide new correction services through the Internet using server and client models with p...

Using GPS system for positioning is subject to several sources of errors: ionosphere and troposphere delays, signal multi-path, number of visible satellites, satellite geometry/shading... A typical civilian GPS receiver provides 6-12 meters accuracy, depending on number of satellites available. This accuracy can be reduced to 1m by using a DGPS (Differential GPS) system which employs a second r...

The additional gain provided on the satellite signals by the HAGR enables sub-meter Pseudo-ranges to be observed directly on the C/A code and also improves the accuracy of the GPS carrier phase and estimates of the satellite signal strength. The directivity of the digital beams created from the antenna array also reduces multipath errors further improving the accuracy of DGPS corrections genera...

The additional gain provided on the satellite signals by the HAGR enables sub-meter Pseudo-ranges to be observed directly on the C/A code and also improves the accuracy of the GPS carrier phase and estimates of the satellite signal strength. The directivity of the digital beams created from the antenna array also reduces multipath errors further improving the accuracy of DGPS corrections genera...

Today, differential GPS techniques allow common GPS receivers to achieve the precision levels required for mapping purposes. The development of systems for mobile Internet access (mainly GPRS) provides a fast and reliable method for feeding differential corrections to a GPS receiver in any area covered by a cell telephone network. With the increase in the available bandwidth, and the example of...

The Differential Global Positioning System (DGPS) is a marine navigation system operating at frequencies of 283.5–325 kHz, which now the primary method for locating vessels in coastal shipping, as well hydrography and mapping systems worldwide. Its positioning accuracy determined by following: pseudorange error to (GPS) satellites, age corrections, value Horizontal Dilution Precision (HDOP), wh...

As the achievable accuracy for single point positioning with GPS is insufficient for many applications, DGPS services have been established all over the world. They can be distinguished into so-called Local Area DGPS services (LADGPS) for small areas such as a country and Wide Area DGPS services (WADGPS) for larger areas such as a whole continent or even worldwide. All of them have in common th...

The Global Positioning System (GPS) can be utilised in a wide range of deformation monitoring applications. During the past few years a methodology has been developed for processing data collected by GPS networks consisting of a mixed set of single-frequency and dual-frequency receivers. The strategy is to deploy a few permanent GPS stations with dual-frequency, geodetic-grade receivers surroun...