A Look at Lasers
Laser technology is, of course, used in several kinds of surveying equipment, including the laser-enabled total station (reflectorless) and the full-blown 3-D laser scanner. But the focus of this survey is on a particular use of laser beams in land surveying-related applications; namely, the rotating level laser and the associated sensors used to receive their signal.
Physical and mechanical improvements of today’s lasers lend to easier setup and use, and a decreased need for more workers. If you’ve considered working as a one-man operation, look to these rotating levels. The simplicity of a laser allows the operator to be more mobile to find the elevation of a given point without the need of a second person. The accuracy levels of lasers continually improve and most models provide a wider measurement range these days. As with most evolving equipment, lasers are more lightweight than before, yet the ruggedness has not been sacrificed. Water-resistant construction lends to rugged fieldwork, and battery life has been extended. Automatic shutoff now saves on battery life and sensors let users know if the alignment is off.
The characteristic of the laser that has made it highly useful in the surveying and construction fields is that the beam is highly collimated, i.e., it is intensely focused and spreads only slightly over relatively long distances. This permits the extension of a line horizontally to establish a known reference elevation; vertically to establish a plumb line or vertical plane; or to set a control line or plane at a predetermined angle of horizontal or vertical alignment. This latter feature, setting a predetermined grade, is a feature of the grade levels shown in the last section of the laser survey found on the following pages.
The 2002 Laser Survey is structured into three main segments: Electronic Levels, Grade Levels and Sensors. The first, Electronic Levels, is the basic rotating level. Its primary function is to establish a consistent level beam at a given elevation (the elevation of the instrument). The Grade Level is the more advanced model mentioned above, which not only can provide a beam at level line-of-sight, but also has the capability of setting a particular grade or slope. They can even be turned on their side so that the beam is vertical, rather than horizontal, thereby providing horizontal alignment as well as vertical. Finally, the Sensor is analogous to the prism in a total station application. It receives the laser beam, providing a positive location of the desired alignment.
Refer to the row headings to get an idea of the various features and capabilities, and how different models compare. This family of equipment has made great strides in capabilities, while prices continue to decrease. Rotating laser levels...definitely worth a look!