A third civil frequency at 1176.45MHz will be added to the GPS system. QZSS (Quasi Zenith Satellite System) proposed by Japan will also have the new signal. This new frequency and the advent of QZSS will greatly enhance the accuracy, reliability and robustness of civilian GPS receivers. One of these enhancements is that it is possible to determine the GPS phase ambiguities more or less instanta...

A new methodology of frequency syntonization using a global positioning system (GPS) carrier phase double differences is presented. The proposed scheme can achieve the traceability of frequency dissemination and obtain the very high frequency stability in the short term, as well as in the long term. The GPS receivers used in our system were elaborately modified in order to estimate the frequenc...

Use of loop aiding for facilitating the operation of GPS receivers in weak SNIR environments has been widely researched in recent years. Locata, a terrestrial radio navigation system working on similar principles as GPS, can also make use of loop aiding techniques with some additional advantages. Locata employs dual-frequency and dual-antenna transceivers (LocataLites) allowing a Locata rover r...

The vulnerability of Global Positioning System (GPS) receivers to jammers is a major concern owing the extremely weak received signal power GPS. Researches have been conducted on variety antenna array techniques be used as countermeasures GPS jammers, and their antijamming performance known greater than that single methods. However, application arrays remains limited because size, cost, computa...

The GRACE mission consists of two identical satellites orbiting the Earth at an altitude of ∼500 km. Dual-frequency carrier-phase Global Positioning System (GPS) receivers are flying on both satellites. They are used for precise orbit determination and to time-tag the K-band ranging system used to measure changes in the distances between the two satellites. The satellites are also flying ultra-...

We propose a simple low-cost technique that enables civil Global Positioning System (GPS) receivers and other civil global navigation satellite system (GNSS) receivers to reliably detect carry-off spoofing and jamming. The technique, which we call the Power-Distortion detector, classifies received signals as interference-free, multipath-afflicted, spoofed, or jammed according to observations of...

In this study we assess the quality of multi-GNSS observations recent Android smartphones. The results reveal a significant drop smartphone carrier-to-noise density ratio (C/N0) with respect to geodetic receivers, and discernible differences among constellations frequency bands. We show that higher elevation satellite, larger discrepancy in C/N0 between receivers Thus weighting scheme may be su...

More and more devices are equipped with global positioning system (GPS). However, those handheld devices with consumer-grade GPS receivers usually have low accuracy in positioning. A position correction algorithm is therefore useful in this case. In this paper, we proposed an evolutionary computation based technique to generate a correction function by two GPS receivers and a known reference lo...

This paper proposes a novel architecture for ultra-tight integration of a High Sensitivity Global Positioning System (HSGPS) receiver with an Inertial Navigation System (INS), to address the issue of GPS tracking and positioning in degraded signal environments. By enhancing signal tracking loops in receivers through the use of optimal controllers/estimators and aiding from external source such ...