CSI Wireless SBX-3, Справочное руководство

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SBX-3 Reference Manual
9
between the base station and remote user over
large distances. As the base station calculates corrections based on
local ionospheric conditions, they may not completely account for the
errors observed at the remote user’s location. This is the root cause of
spatial decorrelation observed over large distances between base
station and remote receivers
The number of satellites visible and their geometry in the sky influences
positioning accuracy. The Dilution of Precision (DOP) describes the
strength of the location and number of satellites in view of the receiver.
A low DOP indicates a stronger potential for better accuracy than a
high DOP. Generally, more satellites visible to both the reference and
remote receivers results in a lower DOP. Additionally, if the satellites
are evenly spread around the receiver, rather than grouped in a few
regions of the sky, a lower DOP (stronger solution) will result.
Satellite signals received by the GPS receiver through 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. 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 many
applications, a small amount of multipath is tolerable.
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 its overall performance characteristics.
More sophisticated, higher accuracy GPS receivers are able to achieve
up to 1 meter of horizontal accuracy 95% of the time using real-time
DGPS beacon transmissions.
1.6 SBX-3 OEM Beacon Receiver
The SBX-3 demodulates RTCM SC-104 differential corrections
transmitted by 300 kHz DGPS radiobeacons. The SBX-3 receiver