CSI Wireless Seres, Reference Manual

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Seres Reference Manual
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1.4.4 GPS Signal Multipath
Satellite signals received by the GPS receiver by a reflection from an object
can decrease positioning accuracy. These multipath signals increase the
measured range to a satellite as the signal takes a longer route to the GPS
antenna. Certain precautions will minimize GPS antenna sensitivity to
these reflected signals. Operating away from large reflective structures such
as buildings or using special antennas and GPS equipment can help to
reduce the impact of multipath. For most consumer-level applications, a
small amount of multipath is tolerable.
1.4.5 GPS Receiver Quality
The quality of a GPS receiver has a dramatic influence on positioning
accuracy. Consumer-based GPS products, such as many affordable
handheld and fixed-mount receivers, typically operate with an accuracy of
3 to 5 meters horizontally 95% of the time. The accuracy of a particular
product depends on the specific receiver’s performance characteristics.
Higher accuracy GPS receivers are able to achieve sub-1 meter horizontal
accuracy 95% of the time using real-time DGPS transmissions. The Seres
receiver / antenna system falls in to this latter category.
1.5 Space Based Augmentation Systems
The US Federal Aviation Administration is in the process of developing a
Wide Area Augmentation System (WAAS) for the purpose of providing
accurate positioning to the aviation industry. In addition to providing a high
quality, accurate service for this industry, this service is available free of
charge to all other civilian users and markets in North America. This
service falls into the greater category of Space Based Augmentation System
(SBAS).
Upon the successful completion of a 21-day test on August 24, 2000, the
FAA announced that WAAS would be running 24 hours per day, seven
days per week from then on. Testing has shown since that this signal is