Spectra Precision FAST Survey Reference Manual - Manual (Page 88)

p86
Latitude: N 42d21 ’28.35882”
Longitude: W 71d08’12.87540”
Elevation: 116.376
Continue with Base Setup?
Yes No
If you like the result, press Yes and continue on. You will then be prompted for the Reference Station Number. This is
an “ID” that will store to the raw file and permit post-processing of the raw GPS data. A typical entry is 0001. The
final prompt will say,
Base Configuration Successful. Save Settings to File?
Yes No
Answering Yes will bring up an entry screen for the reference file name. Reference files are stored with a “.ref”
extension. It is important to save a reference file if you plan to return to the job at another date. Without re-localizing
to control points, you can set up over the same base position, recall the reference file, and enter the new antenna height
for the base position, and start working.
The Read from GPS option is sometimes referred to as “Find Me”. This option is accurate to about 10 to 50 meters,
typically, and it enables the corrections to broadcast with enough accuracy to permit localization and sub-centimeter
real-time work. Be sure that your GPS zone in Job Settings is set correctly before using this option. Also, give the base
enough time to find itself. When first set up, the base receiver has to “collect” satellites and “resolve ambiguities”. If
you Read from GPS too early, you may find a position, but one that is not fully resolved and ends up slowing down the
speed at which the rover fixes.
 Enter Lat/Lon
- Requires you to enter the latitude and longitude for the position of the base antenna. This is useful
if you are setting up over a monument whose latitude and longitude is known. It can also be used over a control
point whose position is known from GPS post-processing. This will put you on the NAD83, NAD27, UTM or
other coordinate system specified in Job Settings, GPS Tab. You can still do a rover-based alignment to transform
to a local system. Rover-based localizations are always improved by more accurate base positioning. If the GPS
detects that your entered Lat/Long is not near the current GPS readings, the program will warn the user.
This method should be used if you are reasonably sure of the accuracy of the latitude and longitude —it should be at
least as accurate as the “Read from GPS” option, or otherwise you will have difficulty getting a “fix” on the rover.