PLATE 1196204 - Caterpillar

GPS Position Error
The accuracy of a GPS position varies according to many different conditions. An "RTK" position is normally accurate enough for construction work. However, this is not always the case.When a GPS antenna is placed in a stationary position and the position output is monitored, there are small changes in the position. The position change is caused by noise in the solution. This results in a small error in the GPS position.The GPS error is an estimate of the amount of noise in the GPS positions.The Role of the GPS Receiver
The satellites are above the antenna so the horizontal and vertical accuracies are different. The vertical position is less accurate than the horizontal position. You can display vertical position error and horizontal position error as text items. Refer to "GPS Accuracy Mode Text Items" for more information.GPS Accuracy Mode Text Items
Three text items that display the current GPS accuracy level can be displayed on the guidance views:
H. GPS Err.
V. GPS Err.
GPS Acc. ModeThe color of the text item shows whether the current GPS error is within the selected GPS accuracy mode limits:
The text item value remains black while the GPS error is less than 90% of the limit defined for the GPS "Accuracy" mode.
When the GPS error is approaching the defined limit, the text is blue.
If the GPS error exceeds the limit of the GPS "Accuracy" mode, the text is red.Selecting the GPS Accuracy Mode
The AccuGrade system will need to be in "Service" mode in order to edit the limits for the GPS "Accuracy" mode.
Turn off the display.
Press the "OK" key and hold the "OK" key. Press the power key on the display.Note: Hold the "OK" key until initialization has started.
For AccuGrade systems running version 10.7 firmware, select "GPS Accuracy " mode within the "Setup Menu - Configuration" dialog.Note: The "Mode" column lists the "GPS Accuracy" modes that are currently enabled for selection. The "Limit" column shows the current "GPS Error Limit" that is set for the "GPS Accuracy" modes.
Press the hard key in order to select GPS (60) .
Illustration 1 g01382606
The "GPS Accuracy Mode Settings" dialog appears. Refer to Illustration 2.Note: By default, the "Edit Modes" soft key is only available when the AccuGrade system is started in "Service" mode.
Illustration 2 g01317037
The group box within the "GPS Accuracy Mode Settings" dialog is labeled in order to indicate the GPS accuracy mode that is currently selected for change.Use the "Fine Mode" soft key, the "Medium Mode" soft key, or the "Coarse Mode" soft key in order to select the GPS accuracy mode that you wish to change.
Use the arrow keys in order to enter a value in the "GPS Error Limit" field. The "GPS Error Limit" defines the maximum allowable GPS error for the selected "GPS Accuracy" mode.
In order to set the "GPS Accuracy Mode" to "Unused", press the "Set Unused" soft key or enter a "GPS Error Limit" of 0.Note: When the "GPS Error Limit" is set to "Unused" for a particular mode, the mode is no longer