Real-time kinematic surveying

RTK GPS surveying is a kinematic technique where a stationary “base station” through the use of a radio modem broadcast carrier phase GPS data to one or more roving receivers. The rover must track satellites in common with the base. The GPS data from both the base and rover are processed immediately in the roving receiver. The result is an accurate 3D vector between the base and the rover. The rover’s position is displayed and logged in “Real-Time”. The main advantage of the RTK surveying is that the quality control of an established position can be carried out in the field. A position is approved if there was:

- static occupation time minimum 5 seconds,

- GDOP < 7,

- 5 satellites,

- position accuracy entered specified before the start of the survey.

What are benefits of RTK GPS surveying? GPS antenna can be mounted on vehicles to provide contour and topographic surveying data continuously. A surveyor can walk a boundary line and survey while walking. Surveyors can find points that are buried or obscured by tall grass, overgrowth and snow because real-time kinematic accuracies are similar to GPS control accuracies. Positions are always overdetermined, feature-coding is done by the surveyor at the detail point and independent checks are easy to make. Equipment can be used by less skilled operators. Real-time kinematic GPS provides the functionality for many of the surveyor’s routine tasks such as: collection of topographic, and cadastral survey data and establishing project control, different stakeout operations etc. One of the main assets of RTK surveying is reducton of the surveying crew: complete work with the equipment can be done by one person.

There are two main drawbacks of the method: the site should be suitable for GPS surveying and survey area is limited by the line-of-sight coverage of the radio link. Radio repeaters could extend the system’s range and radio broadcast GPS data over and around major obstructions such as hills and very large buildings.

Дата добавления: 2015-07-19