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A new solution for GPS infrastructure recently announced overcomes previous limitations with high-precision GPS. Trimble Navigation Limited’s (Sunnyvale, Calif.) Virtual Reference Station (VRS) enables centimeter-level positioning without the need to set up a local reference station. Now users can achieve long-range, real-time kinematic (RTK) precision over greater distances via wireless communications in the field.
The VRS, developed by Spectra Precision’s subsidiary TerraSat, consists of software and a network of Trimble GPS receivers communicating with a control center. The VRS software uses the data to calculate GPS error corrections that are applicable over a wide area. These error corrections are transmitted via wireless communications devices (radios or cellular phones) to users in the field within the network area. Users can also retrieve stored GPS correction data from the control center via the Internet for post-processing.
The system significantly reduces systematic errors in the reference station data to improve reliability and operating range. This allows a user to increase the distance at which the rover receiver is located from the physical reference stations while improving on-the-fly (OTF) initialization times. Traditionally, for precise GPS applications, including surveying, construction, precision farming and high-accuracy GIS, roving receivers required a reference station within 10 kilometers to ensure centimeter level accuracy. With VRS, users can operate at distances up to 50 kilometers without degrading accuracy.