The global positioning system (GPS) provides accurate positioning and timing information that is useful in many applications. In particular, portable consumer GPS applications require cheap compact low-power receivers. This 115mW receiver, implemented in an analog 0.5μm CMOS technology, comprises the entire radio-frequency (RF) and analog sections in addition to the local oscillator (LO) freque...

The use of GPS CIA code measurements for time transfer by means of the so-called common view method is a widely accepted technique. The fuU pdeniiul of the GPS system for time and frequency transfer is, however, only exploited by using all phase and code observables from aU satellites in view. Gedetic processing techniques, adapted to the specifi requirements to process data from specWy modifie...

GNSS-based time transfer is the prevalent technique used in the generation of Coordinated Universal Time (UTC); in September 2011, 56 links out of the total of 67 were GNSS-only. These links are realized by combining the data from a single GNSS receiver in each of the time laboratories involved. Some modern receivers have shown only sub-nanosecond variations, but it has been observed that the i...

Assisted GPS (A-GPS) is being increasingly recognised by the public, users expecting to have a better performance of the A-GPS enabled devices than the conventional GPS receivers. This paper reported the evaluation of several A-GPS enabled receivers using a GPS signal generator and a specifically developed software. Under ideal conditions, several different scenarios were created to test the de...

This paper presents an innovative method to mitigate ionosphere delay error for single frequency receivers. Traditional approach to ionosphere delay correction is carried out through modeling the total electron content (TEC) along each satellite signal path. Because of the large deviation of the TEC during different times of the day, season, and solar cycle from any mean measurements, the ionos...

This paper evaluates the real-time positioning performance of a single-frequency receiver using the 1Hz differential corrections as provided by NASA’s Global Differential GPS (GDGPS) System. While a dualfrequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, a single-frequency user must remove or calibrate this error by other means. To rem...

Scintillation and total electron content (TEC) are the two major examples of top-side ionospheric parameters that recorded differently by most Global Positioning System (GPS) receivers. The new GPS sensor created Atmospheric Space Technology Research Associates (ASTRA), Cornell University, University Texas, Austin have capability to record scintillation TEC fluctuations simultaneously. Hence, C...

GPS has been used widely for many real-time, high precision kinematic applications in the last few years. Such applications cover a wide spectrum of platforms, which take advantage of the very high sampling rates of modern GPS receivers (10-20Hz). These include the "GPS sea swell gauge" and the "GPS seismometer". At the University of New South Wales (UNSW) a number of fast RTK (real-time kinema...

In recent years, many national timing laboratories have installed geodetic Global Positioning System receivers together with their traditional GPS/GLONASS Common View receivers and Two Way Satellite Time and Frequency Transfer equipments. Many of these geodetic receivers operate continuously within the International GNSS Service (IGS), and their data are regularly processed by IGS Analysis Cent...

Wideband signals show promise for Galileo development and GPS modernization because they provide sharper correlation peaks and thus more accuracy. For instance, the Galileo E5 signal occupies the frequency band from 1164 MHz to 1215 MHz, over 25 times the two-sided bandwidth of the GPS C/A code. However, because the ionosphere is dispersive, different frequency components in the wideband spectr...