Spectra Precision FAST Survey Reference Manual - Manual (Page 145)

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offset values as show below. The azimuth can either be specified with respect to north, or with respect to a specified
point. Current GPS coordinates are shown at the bottom, and can be updated via the Read GPS button. When all
necessary data has been entered, you’ll be able to store by tapping Store, or preview the point you’re storing by
selecting Map, or Results.
 Laser Offset:
For more accurate offsets, lasers can be used for either the distance (with direction and vertical
offset entered by the user) or for both distance and direction (where the laser gun includes compass directions). The
Leica Disto, for example, provides distance only. The Laser Atlanta provides both distance and direction. Laser
measurements are popular on construction sites and mine sites where it is dangerous to stand beneath highwalls and
unstable rock conditions. Readings are taken from a safe location to the rock or dirt face. They are also useful for
utility pole surveying and other forms of “windshield” surveys. The laser devices are often mounted on the pole
beneath the GPS antenna. Special poles are available that offset around the lasers, allowing them to mount
vertically, in-line with the center of the pole. If the antenna height is 2.5 meters, and the laser is mounted 0.7 meters
below the antenna and 1.8 meters above the ground, you would enter 1.8 as the laser height. Laser types and laser
height are set by clicking Settings in the LASER tab within Offset. This takes you to the same screen as can be
found from the main menu on the EQUIP tab, under Peripherals. Under the LASER tab, offsets are read
automatically from the laser attached to the serial port. Upon triggering the laser, you will see the reading displayed
in terms of five parameters: Horizontal Offset, Vertical Offset, Slope Offset, Azimuth, and Zenith Angle, as shown
below. The azimuth can either be specified with respect to north, or with respect to a specified point. Current GPS
coordinates are shown at the bottom, and can be updated with the Read GPS button, or you can choose to have the
GPS position read automatically before each point store by choosing Settings and enabling Auto GPS Update.
When all necessary data has been entered, you’ll be able to store by clicking Store, or preview the point you’re
storing by clicking Map or Results. Before you can begin using the Laser offset feature, you must configure the
laser, either by clicking Settings, or by selecting Peripherals from FAST Survey’s main menu. Under the
peripherals menu, you will have to activate your laser, select your laser type, and choose a COM port. It is also
recommended that you deactivate all other peripherals except GPS while using the laser. For more details on laser
setup, see the Peripherals section of this manual. Once you have activated a laser, you may click Read Laser to
begin collecting data from the laser. In order to expedite the data collection process, the methodology for reading an
offset from the laser has been optimized so that you do not need to touch your data collector between shots. This
option can be enabled by selecting Multiread Laser. If you are a first-time user, it is recommended that you disable
this option. If Multiread Laser is disabled, pressing Read Laser will pop up a dialog asking you to trigger the laser,
as shown below. From here, you can either cancel, or fire the laser to record the shot. If Multiread Laser is enabled,
when you press Read Laser, a dialog will appear asking you to trigger the laser, as shown below. Each time you
trigger the laser, a new shot will be collected, and if there was a previous shot, it will be automatically stored.
Between shots, the laser reading and the offset-adjusted position to be stored are displayed. If Auto GPS Update is
enabled during peripheral setup, a new GPS position will be read for each shot. If a bad reading is taken, you can
prevent it from being stored by pressing Reject Last Shot. When finished, click Exit Shot Sequence.