Leadtek LR9805ST User Manual - page 20
LR9805ST GPS Module v1.51Technical Manual
© 2006 Leadtek Research Inc. All rights reserved.
Page 17/19
Preliminary Confidential - Information is subject to change without prior notice.
Dead Reckoning
The process of estimating your position by advancing a known position using course, speed, time and
distance to be traveled. It is figuring out where you will be at a certain time if you hold the speed, time
and course you plan to travel.
Differential GPS (DGPS)
An extension of the GPS system that uses land-based radio beacons to transmit position corrections to
GPS receivers. DGPS reduces the effect of selective availability, propagation delay, etc. and can
improve position accuracy to better than 10 meters.
EGNOS (European Geostationary Navigation Overlay System)
A satellite navigation system being developed by the European Space Agency, the European
Commission, and EUROCONTROL. It is intended to supplement the GPS and GLONASS systems by
reporting on the reliability and accuracy of the signals. According to specifications, horizontal position
accuracy should be better than 7 meters. In practice, the horizontal position accuracy is at the meter
level. It will consist of three geostationary satellites and a network of ground stations.
Similar service is provided in America by the WAAS system. See WAAS.
LNA (Low Noise Amplifier)
A special type of electronic amplifier or amplifier used in communication systems to amplify very
weak signals captured by an antenna. It is usually located at the antenna and is a key component, which
is placed at the front-end of a receiver system.
Multi-path mitigation
Anticipating errors caused when a satellite signal reaches the GPS receiver antenna by more than one
path. Usually caused by one or more paths being bounced or reflected off of structures near the
antenna and occurs to some extent everywhere. The signal which traverses a longer path will yield a
larger pseudo range estimate and increase the error.