For decades the global positioning system (GPS) has been the only space geodetic technique routinely used for inter-continental frequency transfer applications. In the past very long baseline interferometry (VLBI) has also been considered for this purpose and the method’s capabilities were studied several times. However, compared to GPS current VLBI technology only provides few observations per...

In this contribution we give a brief review of the theory of integer estimation as it has been developed for use with the Global Positioning System (GPS). First we consider the GPS observation equations (GPS and Integers). These observation equations are not of the usual type, since some of the parameters are known to be integer. This implies that an extention of ’classical’ adjustment theory i...

In rapid static or kinematic positioning, especially with single frequency and shorter period GPS phase observations, the normal matrix may be weak multicollinear since the GPS satellite’s positions and geometries are changing slightly. Therefore the conventional least squares float solution may cause large biases due to the weak multicollinearity and thus make the ambiguity search techniques f...

The development of low cost, small size antenna arrays and digital antenna electronics has resulted in small, affordable GPS phased arrays and digital receivers that are suitable for commercial applications. NAVSYS Highgain Advanced GPS Receiver (HAGR) product includes the capability to spatially process signals from up to 16antenna elements. Previous papers have presented the HAGR’s capability...

We provide an assessment of the backpropagation (BP) method for processing GPS radio occultations using simulations as well as recent data from CHAMP and SAC-C. It is found that BP gives improved retrievals over the standard Doppler technique, even when multipath ambiguities are not completely removed. In addition, by being an amplitude-weighted algorithm, BP is robust in the presence of receiv...

Personal digital assistants or mobile phones applications are not anymore restricted to multimedia or wireless communications, but have been extended to handle Global Positioning System (GPS) functionalities. Consequently, the growing market of GPS capable mobile devices is driving the interest of software receiver solutions as they provide several advantages with respect to traditional hardwar...