ALTERNATOR GROUP 1N9936 - Caterpillar

Illustration 1 g01374212
GNSS levels of position accuracy
(1) Autonomous
(2) DGPS
(3) RTK Fixed
(4) RTK Float
(5) SBASIllustration 1 shows the levels of accuracy for GNSS.Listed below are the five basic levels of position accuracy that are available.Autonomous - 10 m (30 ft) to 15 m (50 ft)SBAS - 1 m (3.3 ft) to 2 m (6.6 ft)DGPS - 0.3 m (1.0 ft) to 1.0 m (3.0 ft)RTK Float - 0.2 m (0.7 ft) to 1.0 m (3.0 ft)RTK Fixed - .02 m (.07 ft) to .03 m (.10 ft)
Illustration 2 g02552859
GNSS and the Cat Grade Control System
(1) GNSS Satellites
(2) GNSS Base Station and Data Radio
(3) Repeater radio (optional)
(4) Machine equipped with the Grade Control systemThe method that is used for machine grade control in construction is the same used by surveyors for stakeout in construction. The method is called Real-Time Kinematic (RTK) GNSS.Two GNSS receivers are required to produce RTK positions. One GNSS receiver is known as the GNSS base station. The GNSS base station has a fixed position. The other GNSS receiver is known as the rover. This receiver is mounted on the machine.The base station communicates to the rover through a wireless data link using a data radio. Illustration 2 shows this setup.Both GNSS receivers make observations (measurements) of the GNSS signals at the same time. The base station broadcasts the observed information together with the location and other information across the data radio link to the rover. The rover then combines the data from