Tacheometer
A distancer (also Disto, Distometer, LaserDisto, Distomat ) is a device for optical distance measurement. There are hand-held devices for easy surveying work or craft or devices which are placed on the theodolite (weight about 0.2 to 0.5 kg ). In modern total stations, these are usually already built in miniature form. Solenoids are in construction surveying and geodesy
Technology
Distancer largely based on the time of flight measurement or the measurement of phase shifts of infrared or light waves and can measure distances up to several 100 m to cm exactly. To avoid ambiguous solutions in a measurement, various pulse repetition frequencies are used (rough measurement and precision measurement ). Convenient device versions can be calculated from the measured values of areas and volumes, or save the results with attributive information for later analysis on a computer.
More sophisticated instruments to achieve this accuracy over several kilometers, if so-called prism reflectors are used at the destination point. Less accuracy is there are devices, which also extend reflective films at medium distances, for near even the diffuse reflection eg a house wall.
Geometrically, the distance measurements are to be treated as an oblique lines which still require measuring their slope or the angle of elevation for their conversion to horizontal distances.
Historical
The first practicable, but still quite bulky distancer came 1963-1972 on the market. They work instead to light or microwaves, and 20-50 cm parabolic antennas, for example, the devices DI50 and 60 of the company Wild Heerbrugg.
In the 1970s, the distance measurement prevailed with light and infrared lasers. First, the distancer were still own measurement units, which had to be placed instead of the theodolite on tripod and therefore distances were used only for long (rarely to be measured ). Among the most popular devices, the wild - Distomat part series, while Kern Aarau built the smallest and most accurate devices, including the Mekometer.
Itemization
- Geodetic instrument
- Markscheidewesen
- Laser Technology
- Engineering Geodesy