NavCom RT-3020 Rev.D - Manual (Page 27)

RT-3020 User Guide - Rev. E
Basics of RTK Surveying
The idea behind RTK surveys is to achieve the high
quality, low ambiguity accuracy of post-processed
position fixes, in a real time environment. In order to
accomplish this task, the
GPS data collected at the
roving sensor must have its error sources inherent to
GPS corrected as much as possible. These errors will be
accounted for virtually instantaneously; thus the Real
Time in
RTK .
Setting up a Reference (Base) Station can minimize GPS
errors in a roving GPS sensor. The reference GPS sensor
would be set up on a known surveyed location, with
this position locked in. It would then transmit its code,
clock, and
reference station coordinate information to
the roving sensor. The roving sensor would use this
information to correct each
GPS measurement it
receives.
In the RT-3020 this link between the reference station
and the rover is achieved via a 2-way, 2.4GHz Spread
Spectrum Radio ( SSR ) integrated into the RT-3020. This
SSR was designed specifically with GPS RTK in mind. It
has built in interference rejection so any extraneous
radio signals will not interfere with the transmission of
the correction data.
The RT-3020 when configured as a reference sta ion
can transmit corrections to any number of roving
receivers capable of picking up the radio signal and
decoding one of the three GPS correction formats
[ RTCM , CMR, or NavCom proprietary] transmitted. At
2.4Ghz, data being broadcast via modulated radio
carrier frequency is limited to line of sight for error free
reception. However, the signal can be received in less
than ideal environments, though some data loss could
occur. The
SSR integrated into the RT-3020 has a line of
sight range up to a maximum of 10km.
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