In this paper, a novel compact band pass filter (BPF) is proposed for Global Positioning System (GPS) receivers. The proposed BPF configuration is composed of a low pass filter (LPF) section formed by the coupled line transformer connected with a radial stub and two short circuited stubs embedded within the 50Ω microstrip line connecting the input/output (I/O) port of LPF. The lumped equivalent...

Abstract This paper describes a new switching topology of a sampling mixer for SAW-less GPS (L1 band) receivers. The GPS receiver with the new mixer achieved NF 2.5dB and good blocking performance. In an alternative implementation, the mixer is stacked under a Quadrature VCO to reuse supply current. As a result, the current consumption of the GPS receiver is 11mA from 1.8V supply while maintain...

This application note investigates the basic theory of software-based receivers for L1-band civilian GPS applications, including a discussion of signal acquisition and tracking, and the need for bit synchronization in the receiver. It then details a low-cost method for adding GPS capability to laptop PCs through a USB dongle with the MAX2769 universal GPS receiver. A similar version of this art...

the gravity recovery and climate experiment (grace), twin satellites launched in march 2002, are making detailed measurements of the earth's gravity field. it will yield discoveries about gravity and the earth's natural systems. different sensors and instruments have been placed in the grace satellites to fulfill the primary scientific objective of the mission in mapping the earth’s g...

There is a need for improved antenna performance in view of a recent decision by the DOD to disable SA at L1 GPS channel. For single frequency receivers SA had been the main cause of the largest errors of code and carrier phase measurements. With SA turned off, the multipath, ionosphere and antenna phase center variations are now the biggest contributors to code and carrier phase measurements. ...

Global positioning system reflectometry (GPS-R) is an emerging area of GPS applications in microwave remote sensing using multipath reflected signals. Soil moisture estimation is one of the many potential applications of the GPS-R technique. The focus of this study is on investigating the feasibility of soil moisture estimation based on GPS L1 band interference signals which can be readily capt...

A RF front-end chip for a dual-band Global Positioning System (GPS) receiver for L1 and L2 bands is designed using 0.25 μm CMOS technology. All function blocks of the GPS front-end are integrated onto one chip. The low noise amplifier has input matching over a wide frequency range to handle the L1 and L2 bands. This receiver uses a dualband image-reject mixer with the quadrature mixer sharing a...