RTK Setup Guide
The following is a
concise step-by-step guide to setting up the Trimble equipment for RTK
surveying. It does not cover the theory of operation; these instructions are
much more useful after an introduction to the system.
Base Station Setup - do this first
1.
GPS Receiver
1.
Setup GPS antenna tripod
and tribrach; insure that the optical plummet is aligned with the base station
benchmark, and that the tribrach is level.
2.
Attach GPS satellite
antenna ("GPS antenna") to the tribrach via the brass adapter. Attach
GPS antenna cable (yellow 3-shell [large] Lemo to right-angle coaxial
connector) to the antenna.
3.
Connect the base station
battery (use the attached cable) to port #2 of the GPS receiver.
4.
Connect the GPS antenna
cable to the receiver's antenna port (labelled, and the only port that fits).
5.
Connect the data
collector I/O cable to receiver port #1; the cable is black, with 0-shell
[small] Lemo connectors on each end. One end is straight, the other a
right-angle. Connect the right angle connector to the receiver.
6.
Place the receiver
inside the transport case (for weatherproofing). Be sure not the have any sharp
bends in the cables, and do not clamp the lid on any cables.
7.
Connect the data
collector to the other end of the data collector I/O cable connected to
receiver port #1.
8.
Turn on the data
collector and GPS receiver by pressing the green power button on the data
collector.
9.
Measure the GPS antenna
height using the Height Rod. Measure at 3 points (120 degrees apart). Always
measure from the benchmark stamp to the bottom edge of the groundplane, inside
a notch. Record the three measurements; if they are different by more than a
few mm, check level and centering of the GPS antenna. Average the readings and
enter the average into the data collector when prompted; either enter in
meters, or type in the number followed by the unit (e.g. cm for centimeters).
Check that the measurement type is set correctly.
2.
Base radio
1.
Choose a location more
than 10' from the GPS antenna. Do not choose a location near trees, cars,
buildings, etc.
2.
Setup tripod with
tribrach, levelling at the highest possible stable height.
3.
Attach the radio antenna
cable to the tribrach with the brass adapter. If possible, use 2 pieces of the
radio mast to increase the height of the radio antenna; save the 3rd piece for
the Rover system, if not using the 2m rangepole.
4.
Attach the radio
antenna, with tip (0dB or 5dB), to the radio antenna cable.
5.
Put the base radio near
the radio antenna, preferably in a sheltered location. At the very least, place
the cooling fan downhill without restricting airflow.
6.
Connect the radio
antenna cable to the radio; there is only port that will work, and it is
labelled.
7.
Connect the power cable
to the radio; there is only one port that will work, and it is labelled. Be
sure to align the red dot and mark before pushing with any force.
8.
Connect the donut lugs
on the power cable to the battery; red to positive.
DO NOT CONNECT
WITH REVERSE POLARITY; the 10A fuse in the cable will blow, and it is
possible to damage the radio.
9.
Connect the green ground
cable (spade lug to alligator clip) to a real Earth ground. If no metal is
readily available, use a piece of metal bar driven into the ground.
10.
Turn on the radio;
remove the removable faceplate, and use the black knob. This is also the volume
control.
11.
Select a channel that is
not in use. Preferably avoid channels 15 and 16, as the FCC has an unusually
large number of complaints on these channels. Make sure that the status light
is green, indicating the use of Carrier Detect; changing carrier
detect requires use of a PC and the COMMSET program.
12.
Once a channel is
selected, close the faceplate and note the channel number; this will be needed
for the rover.
13.
Connect the base radio
data cable (30m flat yellow jacket, 1-shell Lemo [medium] to 0-shell Lemo) to
the GPS receiver port #3.
3.
Start the base station
measurements
1.
Make sure that the
correct Job is selected on the data collector. New Jobs may be defined in
the Files mode.
2.
On the hand controller,
choose Survey, and then choose the appropriate Survey Style;
typically Trimble RTK or a custom style. New styles may be
defined at this stage, or in the Survey Stylesoption in the Configuration mode.
3.
Choose Start
base station. Type in the benchmark name, and the position, if known. If no
position is known, the Here softkey will use the current GPS
position. This is not very accurate, and is not recommended for precision work.
4.
Press the measure softkey,
and disconnect the data collector when instructed to do so. Do not turn
off the base receiver. Check that the satellite LED (red) is blinking
slowly on the GPS receiver, and the transmit light (labelled "TX") on
the base radio blinks once per second. This indicates everything is working
correctly.
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