User's Manual

7 AutoBase Feature
62 SPSx80 and SPSx81 Smart GPS Antennas User Guide
Setting Up a Base Station
The AutoBase feature influences how you set up an SPS781, SPS880 Extreme, or
SPS881 Extreme
Smart GPS antenna as a base station. Before the receiver can transmit
RTK corrections (that is, operate as an RTK base station), the current position of the
receiver must correspond to a previous base station position. The base station
position—latitude, longitude, and height—must be part of the GPS site calibration.
Note – There is no need to configure the base station receiver settings manually.
1. To perform the first base station setup at a new location, always use the SCS900
Site Controller software to initialize the SPS781, SPS880 Extreme, or SPS881
Extreme
Smart GPS antenna on a new point. You generally do this only once, the
first time that you occupy the point, but see the Caution below.
When the base station setup is complete, the receiver generates and stores an
application file that contains the parameters for that location.
C
CAUTION – When you perform a future base station setup at the same location, the
receiver assumes that there has been no change to either the antenna height or the
antenna height measurement method used previously. It is therefore essential that you
keep the antenna height constant between setups.
If there is any risk that the antenna height might have changed, you must use the SCS900
Site Controller software to start (and so reset) the SPS781, SPS880 Extreme, or SPS881
Extreme
Smart GPS antenna. From the SCS900 Site Controller software, select Start Base
Station.
2. To perform a future base station setup at the same location, simply press the
Power key on the receiver. The receiver turns on, determines its location, finds
the appropriate application file, initializes the settings, and starts to broadcast
RTK CMR+ corrections through the internal radio or through the external radio
(whichever radio was used the previous time).
If the receiver uses an external radio, such as an SNB900 radio, the AutoBase
feature raises the Bluetooth
®
wireless connection to the radio. If a Bluetooth
connection is not used, the AutoBase feature searches the receiver
communications ports for the external radio. When the receiver finds the
external radio, the receiver transmits RTK CMR+ corrections to the radio.
Best practice
After each new base station setup, and at the start of every measurement session,
Trimble recommends that you measure one known point to verify that the position
and height errors are within tolerance. The measurement takes only a few seconds, but
can eliminate the gross errors typically associated with daily base station setup.