نتایج جستجو برای: single frequency gps receivers

تعداد نتایج: 1335672  

1994
Alison Brown Jarrett Redd

There is growing concern regarding the ability of GPS receivers to operate in the presence of in-band or nearband interference. In-band interference can occur deliberately from GPS jammers or naturally from spurious harmonics from nearby electronics that generate signal products that land in the GPS signal band. To support development and testing of GPS receivers in an interference environment,...

2007
MICHAEL BEVIS THOMAS A. HERRING RICHARD A. ANTHES

We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is retrieved ...

This paper proposes a new method for rejecting the Continuous Wave Interferences (CWI) in the Global Positioning System (GPS) receivers. The proposed filter is made by cascading an adaptive Finite Impulse Response (FIR) filter and a Wavelet Packet Transform (WPT) based filter. Although adaptive FIR filters are easy to implement and have a linear phase, they create self-noise in the rejection of...

2004
K J Parkinson

The precise time available from the atomic clocks orbiting the earth in GPS satellites is used in many systems where time synchronization is important. The satellite clocks are monitored and adjusted by ground based control telemetry to within one microsecond of Universal Time. A number of commercial GPS receivers have the ability to provide a time synchronised output, typically one pulse per s...

2013
Yassine SALIH-ALJ

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...

2004
Dan Nobbe

and-held GPS receivers are used by soldiers to find their way in strange lands, especially at night. H GPS receivers are also used to find downed pilots and locate other strategic personnel. After the Gulf War, the U.S. Army announced it would install GPS in all armored vehicles to help minimize friendly fire incidents, which was a major source of casualties in Operation Desert Storm. Friendly ...

2003
Tomas Beran Donghyun Kim

The objective of the research described in this paper is to develop a Kalman filter-based functional model for single-frequency positioning which is suitable for low dynamic platforms such as cars or boats. No external sensors are used and the precise velocity information comes from the time-differenced carrier-phase measurements. The Kalman filter combines these measurements with undifferenced...

2008
Andreas Grillenberger Rodrigo Rivas Markus Markgraf Peter Mumford Kevin Parkinson Chris Rizos

GPS is a well established navigation system in current spaceflight missions. Affordable GPS receivers for small satellite and sounding rocket missions are usually based on Commercial Off The Shelf (COTS) products. Many of these receivers are limited to single frequency tracking and utilise custom ASICs for the signal processing. The Phoenix receiver is an example of a commercially available rec...

2004
C. Brock

The National Imagery and Mapping Agency (NIMA) operates a worldwide network of GPS monitoring stations that utilize high performance Cesium Frequency Standards and geodetic quality GPS receivers. The NIMA Monitor Station Network (MSN) operates continuously, and has been in operation for more than seven years. The frequency standards are located in nonlaboratory environments and logistically cha...

2007
Christian Weber Andriy Konovaltsev Michael Meurer

This paper presents new findings about radio interference threat in L1/E1 frequency band of GPS and coming Galileo. The results of a dedicated interference measurement campaign are presented. One type of the interference encountered during the campaign on several locations inside Germany has been modelled and the impact of this interference on massmarket GPS/Galileo L1 receivers has been assess...

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