The atmosphere sounding experiment of the German CHAMP (CHAllenging Minisatellite Payload) satellite mission was activated on February 11, 2001. Since then more than 110,000 occultations were recorded as of mid-December 2002. The results of nearly two years CHAMP GPS (Global Positioning System) occultation measurements and data analysis have shown, that significant improvements of the GPS radio...

Increasing GPS precision at low cost has always been a challenge for the manufacturers of the GPS receivers. This paper proposes the use of a Wiener filter for increasing precision in substitution of traditional GPS/INS fusion systems, which require expensive inertial systems. In this paper, we first implement and compare three GPS signal processing schemes: a Kalman filter, a neural network an...

Abstract: The availability of GLONASS would bring significant benefits to geodetic applications of global positioning systems. GPS and GLONASS observations could be combined directly in the data processing; as a result, the geometry of observed satellites could be enhanced by increasing the number of available satellites. Up to now, with the recent revitalization of GLONASS, more high precision...

OBJECTIVES To describe the management of vaginal discharge in general practice, with particular regard to the use of the high vaginal swab (HVS), and to compare GPs' expectations of this test with the processing and reporting undertaken by different laboratories. METHODS A postal questionnaire survey of 2146 GPs in the North Thames area and postal questionnaire study of the 22 laboratories se...

NAVSYS' High-gain Advanced GPS Receiver (HAGR) has been designed to take advantage of digital adaptive antenna array spatial-processing to enhance the accuracy of the GPS observations. The HAGR has the capability to create an optimized digital antenna pattern for up to eight GPS satellites simultaneously. This is used to perform dynamic beam-forming to the GPS satellites, in both static and mob...

GPS is a CDMA system using DSSS, and the length of the C/A cod used by GPS L1 band civil signal is 1023chips. As the Cross-Correlation peak between the C/A codes is not zero, it will degrade the performance of the detection probability. Detection of weak signal is becoming important in many applications like GPS remote sensing etc. Cross-Correlation caused by GPS Gold codes are representing sig...

This paper presents a new structure for fast GPS receivers. The suggested GPS acquisition scheme leverages a systolic-based array structure of regular and simple locally-connected processing-elements (PEs). The new GPS system is simulated and its complexity is evaluated for a real-time implementation on a field programmable gate array (FPGA). The proposed systolicbased acquisition system promis...

A continuous GPS array is a very useful tool for monitoring and modeling crustal activity. GPS observation has revealed various unknown aspects of tectonic deformation in Japan and other locations. Quasi-real time data acquisition and dense spatial coverage enable incorporation of GPS data into simulation models for crustal activity forecast, which is similar to data assimilation in weather for...

This research evaluates the quality of GPS signals and their usability for localization in urban environments. GPS signals collected on a Software Defined Radio (SDR) platform in urban canyons in Columbus, Ohio (USA) are processed using a deeply integrated GPS/INS scheme. This architecture allows for coherent signal integration with continuous carrier phase tracking for intervals as long as one...