CORE - EVAPORATOR 1868896 - Caterpillar

A wireless link between the radios is used for communications. Refer to Illustration 4. The link consists of two radios that transmit data. One radio is located at the base station. This radio is known as the "base station" radio. The second radio is located on the compactor. This radio is known as the rover radio.Both the base station receiver (8) and the rover receiver that is mounted on the compactor (9) perform simultaneous measurements of the signals from the satellite system (6) .The base station uses the radio (7) in order to broadcast the information across the link to the rover radio (11) that is on the compactor.One base station can support an unlimited number of receivers. The receivers must be within 20 km (12.4 miles) of the base station.Note: 20 km (12.4 miles) is a nominal range. The range is based on ideal conditions.A repeater radio (10) is used in order to increase the strength of the information from the radio at the base station. The information is sent from the base station. The repeater receives the information. The information is sent from the repeater to the radio on the compactor. This repeat broadcast provides coverage when the compactor is out of the range of the base station. A repeater is also used when the transmissions from the base station are obstructed by hills or by buildings.Note: The TC900C radio is recommended in areas that have the 900 MHz band. The TC450C radio is recommended in areas that do not have the 900 MHz band.The AccuGrade System combines the data from the rover receiver and the data that was received from the base station. This combined information is used in order to compute a very accurate position of the drum relative to the known coordinates of the base station.The radio signals that are received by the GPS receivers are very low power. Although the signals pass freely through clouds and dust, the signals are easily disrupted by trees, or by structures such as bridges and overpasses. These disruptions may be caused by any of the following:
The signal can be lost if the compactor moves out of the sight of one or more satellites.
This signal can be lost if the compactor moves under an object that disrupts the signal.
The signal can be lost if one or more satellites move below the horizon.Because of the possibility of disruption, particular attention should be given to the quality of the information that is being received. The quality should be suitable for the type of work that is being performed.Satellite-based Augmentation System
A Satellite-based augmentation system (SBAS) is a low precision GPS method that can be used for grade control. SBAS systems do not require additional infrastructure on the site. This method should only be used when the infrastructure for an RTK Fixed method is not available. Additional positioning errors are inherent to this method. An SBAS network uses the following devices for error correction:
Ground stations that are located at known positions