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In recent years, the real time GIS Market has obvious tendency towards position availability, reliability and accuracy improvement. Many users are not satisfied with standard open sky meter level and seek for (sub) foot accuracy in real-time.
The key requirements which currently allow such a level are: working with multiple GNSS signals, applying differential mode with internal or external communication devices, and using high quality antenna. Such a configuration, either of Smart Antenna type with a controller, or a handheld GNSS receiver with external antenna and communication devices, will result up to cm level (GNSS RTK) accuracy.
But many GIS users are looking for improvement with not so expensive handhelds without external antenna and external communication modules. Ashtech has developed a real time technology which allows to get wide spectrum of GIS accuracy (from meter level down to cm depending on configuration and environment) using single GNSS handheld receiver. Such a technology allows getting meter level standalone position, sub-meter level SBAS differential position and decimeter level float RTK position against single base or Network. For short open sky baselines receiver can ultimately provide cm level accuracy with high availability. The paper describes the challenges to get improved positioning with sole handheld unit and provides real life performance assessment for different operation modes and applications. As a final supplement, we describe what additional GNSS performance may be delivered when in addition a high-grade external antenna is connected to a handheld receiver.
