This paper presents an overview of technical developments within the CRCSI-funded research on "Delivering Precise Positioning Services in Regional Areas" undertaken by the authors since mid-2007. The research aims to address the technical and business issues that currently constrain GPS-based local area RTK precise positioning services so as to operate in future across larger regional areas, an...

Dual-frequency GPS TEC monitors have been used to study the response of the ionosphere to the solar eclipses of 22 July 2009 and 15 January 2010. The receivers were located at three stations, Calcutta, Kharagpur and Baharampore which are situated outside the umbra zone in the Indian longitude sector with each baseline being ∼200 km. Effects of obscuration of the solar disc were noted in the amb...

To perform the most precise relative positioning using GPS, it is necessary to resolve the carrier-phase integer cycle ambiguities. This process becomes increasingly difficult as the distance between the mobile and reference GPS receivers increases, due to the decorrelation of the GPS errors with distance, resulting in a practical limit on the distance over which ambiguity resolution can be per...

Though accelerometers have been used to monitor the deformation/deflection of large structures after they are built, relative displacements between different parts of the structure during severe weather conditions cannot be measured accurately due to the lower band limit of accelerometers. Therefore, the current design of large structures can only be termed as being of a "partially closed-loop ...

GLONASS has been proposed as an augmentation to GPS/LAAS. We examine the incremental benefits of the additional signals from GLONASS to the availability of service for precision approaches. The methodology used for the modeling of availability is the same as that adopted previously for the analysis of GPS/LAAS. The inclusion of GLONASS signals requires provision for adapting the models of measu...

The Global Positioning System (GPS) based time reference provides inexpensive but highly-accurate timing and synchronization capability and meets requirements in power system fault location, monitoring, and control. Precision satellite clocks and time measurements are the keys to the accuracy of GPS. A stand-alone civilian user enjoys an accuracy of 25 meters and 200 nanoseconds. Five methods, ...

Modern GPS carrier phase-based survey techniques such as "rapid static" and "stop & go" are fast becoming the standard operational modes for building local geodetic control networks or for the densification of an existing network. However, such techniques do have some challenges when used together within a single survey project. For example, these mixed-mode GPS surveys do result in incompatibl...

In the past decade or so there has been increasing interest in the use of permanent, continuously-operating GPS networks, with a small number of continuous networks having been deployed in the USA, Japan, Canada and Europe for large scale crustal motion studies. However, only in Japan has a country-wide continuous GPS network to support seismic research been established by the Geographical Surv...

Global positioning system (GPS) data processing algorithms typically improve positioning solution accuracy by fixing double-differenced phase bias ambiguities to integer values. These “double-difference ambiguity resolution” methods usually invoke linear combinations of GPS carrier phase bias estimates from pairs of transmitters and pairs of receivers, and traditionally require simultaneous mea...

Weak GPS signal tracking is studied in this paper. To utilize the spatial correlation of the GPS signal among local receivers, a collaborative signal tracking structure is proposed. More specifically, the GPS signal parameter, carrier Doppler from a nearby receiver is provided to the target receiver as reference. An open-loop batch processing technique is used in this study, mainly to take adva...