Basics of rtk surveying – NavCom RT-3020 Rev.D User 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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