Terrestrial Engine RT Properties

When you add the Terrestrial Engine RT module, the Terrestrial Engine RT Properties dialog appears with this tab.

If you select the module in the Tree view after you have added the module, the categories and settings of this tab appear in the Properties view.

Use the General Settings tab to view and edit the Terrestrial Engine RT properties, such as the synchronization options and usage of current meteorologic sensor data.

Synchronization category

The settings of this category specify the source and age of the data to be processed. The Terrestrial Engine RT processing rules apply, which basically means the same synchronization and processing logic apply in the Integrated Survey Engine and in the Terrestrial Engine RT. In other words: the Round synchronization of the Data Collector modules will trigger a new computation process.

Select Data Collectors / Data Receivers: Specifies the number of Data Collectors and/or Data Receivers of a mission processed together. To select the modules, set the focus into the value field and click the browse button. The Select Data Collectors or Data Receivers dialog appears.

Delay before processing: Only available, if the Select Data Collectors / Data Receivers property is set to more than one Data Collector or Data Receiver module. The data of the selected modules are considered to contribute to the same set of rounds and are processed together, if they all arrive at the Terrestrial Engine RT module within the period specified here. Selectable delay periods are between 5 minutes (default value) and 2 hours.

Maximum age of round: Only available, if the Select Data Collectors / Data Receivers property is set to more than one Data Collector or Data Receiver module. Specifies a maximum age of a set of round measurements to be processed together.

Note - If for a Data Collector module a new site setup has been performed, processing of a new set of rounds will start immediately after data of that module having arrived. The Delay before processing and Maximum age of round values will not be applied.

Meteorological Sensor category

Use sensor: Specifies whether current temperatures are used to correct the total station measurements. If set to No (default value), the Terrestrial Engine RT module uses the temperature specified for each Data Collector module in its Temperature property. If set to Yes, two additional settings appear, which specify the Temperature Sensor module related to a thermometer and the age of data.

Selected sensor: Only available, if the Use sensor property is set to Yes. Specifies the sensor contributing to this configuration. To select a sensor that is configured either with a Temperature Sensor module or a Data Logger module, set the focus into the value field and click the browse button. The Select Meteorologic Sensor dialog appears.

Age of measurement data: Only available, if the Use sensor property is set to Yes. The value given here is added to the actual time the measurement of a set of rounds needs twice, once in advance and once thereafter. Thus this value specifies the period during which temperatures are taken into account for a specific set of rounds. For example: The measurement of a set of rounds starts at 13:10 with the first measurement of the first round and ends at 13:22:36 with the measurement of the last target of the last round. The current Age of measurement data value is 5 minutes. In this case, the last temperature value available for the period between 13:05 and 13:27:36 is applied for correcting the measurement data.

If for the specified period no temperature value is available, a Temperature sensor data missing alarm is issued. The module nevertheless processes the data: It uses the fixed temperature value for correction, as if the Use sensor setting were set to No.

Station Scale Factor category

Scale factor: If you know that a tension exists between the measurements and the reference coordinates provided for the site, one can apply a scale factor or the module can compute a scale factor and apply it to the measured distances.

Measurement Correction category

Instead of applying global corrections (which you can specify for each Data Collector module using the settings of its Weather Condition category), the Terrestrial Engine RT module can apply corrections from concurrent comparison measurements to a reference target. The software automatically chooses one of the targets selected as reference, namely the point with the minimum difference in horizontal direction to the monitored point.

For a reference point, Terrestrial Engine RT compares the calculated with the measured value. The difference of these values is transferred to a correction applied to the measured value(s) of the monitored points. Corrections are calculated for either the distance (if you are setting the Correct distance ppm property) or the vertical angle (if you are setting the Correct vertical angle property) of a monitored point.

Distance ppm correction: Specifies the total station(s), for which the distance measurement will be corrected for atmospheric influence. By default, no total station is selected. If you have selected one total station, its point name appears here, with several total stations, the number of total stations shows up. For each total station selected here, the measurements are controlled with atmospheric corrections parts per million [ppm]. To edit the selected total stations, set the focus into the value field and click the browse button. The Select Total Stations dialog appears. After you have selected at least one total station, additional properties are available for editing.

Vertical refraction correction: Specifies the total station(s), for which the measurement of the vertical angle will be corrected for refraction errors. By default, no total station is selected. If you have selected one total station, its point name appears here, with several total stations, the number of total stations shows up. For each total station selected here, the measurements of the vertical angle are corrected using the refraction model derived from the reference measurement. To edit the selected total stations, set the focus into the value field and click the browse button. The Select Total Stations dialog appears.

Choose reference targets: Only available, if there are total stations selected for distance or vertical angle corrections. Specifies a list of points to be used as reference targets for distance or vertical angle corrections. To edit the list of reference points, set the focus into the value field and click the browse button. The Select Reference Targets dialog appears.

Maximum angle difference to a reference point: Only available, if there are total stations selected for distance or vertical angle corrections. Defines a maximum difference in horizontal angle between a measured point and its reference point. If no reference point exists inside this sector, the measurements of a point will not be corrected using reference point measurements. In this case, the global corrections derived from the temperature and the refraction coefficient are applied.

Decrease vertical angle corrections: Only available, if there are total stations selected for vertical angle corrections. If set to Yes, the corrections for the vertical angle are decreased linearly from 100% to 0% up to a specified distance from the reference point. To specify this distance, use the Maximum coverage distance property, which will be available if the Decrease vertical angle corrections property is set to Yes.

Maximum coverage distance: Only available, there are total stations selected for vertical angle corrections. Defines the maximum distance between a reference point and a monitoring point up to which a measurement will be corrected by a reference measurement. If the distance exceeds the defined value, the refraction constant set in the Data Collector will be used for corrections.

Setup Alarm Thresholds category

Alarms can be triggered on residuals in one or more directions: Distance; Lateral; Vertical. If the computed residual is higher than the values set here, the processor triggers the Station Setup Residuals Alarm alarm. The default values for Distance and Lateral are 0.030 meters, for Vertical it is 0.050 meters.

HDOP Thresholds category

The geometry of a total station setup is a vital factor for all subsequent measurements. If the line of sight to a control point is blocked, the quality of the station setup will decrease and it can lead to jumps in prism displacement although no physical movement happened. To determine the horizontal quality of the geometry of a station setup the Horizontal DOP (Dilution Of Precision) is a good measure. This statistical value indicates the quality of the geometry. Sets of rounds resulting in insufficient HDOP values will either trigger an alarm or will not be forwarded to the adjustment functionality of depending Integrity Monitor modules.

Tip - Use the Residual History module-view for a list of the current Horizontal DOP values.

Use the properties of the HDOP Thresholds category for enabling the triggering of events such as warnings or alerts to be issued or sets of rounds to be rejected. Two different alarm modes - alert or warning - can be configured, where the alarm thresholds for a warning should be more limited than those for an alert.

Warning rating: This setting pertains to the alarm in warning mode to be triggered. A warning may tell the operators that the DOP value seems to be quite high and they should have a look at the setup. Use the selections of the value field to enable triggering a warning and to select a specific rating. The thresholds for a warning should be more limited than those for an alert. For the available selections see the table of HDOP ratings below.

Warning threshold: Only available if the Warning rating property is set to Custom. Specifies a threshold to be exceeded before a warning is issued.

Alert rating: This setting pertains to the alarm in alert mode to be triggered. An alert tells the operator that the DOP value is too high and the measurement (set of rounds) should be rejected. Use the selections of the value field to enable triggering an alert and to select a specific rating. The thresholds for an alert should be less limited than those for a warning. For the available selections see the table of HDOP ratings below.

Alert threshold: Only available if the Alert rating property is set to Custom. Specifies a threshold to be exceeded before an alert is issued.

Rejection rating: This setting pertains to the rejection of measurements. Use the selections of the value field to enable the rejection of the set of rounds when the DOP is too high, and to select a specific rating. The thresholds for rejection should be less limited than those for a warning and might be equal to those for an alert. For the available selections see the table of HDOP ratings below.

Tip - If you enable measurement rejection based on a bad HDOP (that is, select a value different from None), it may be a good idea to specify the same value for the Alert rating as for the Rejection rating. In this case, the alert the operator receives implicitly is the information on the rejection of the current set of rounds.

Rejection threshold: Only available if the Rejection rating property is set to Custom. Specifies a threshold to be exceeded before a set of rounds is rejected and not forwarded to depending Integrity Monitor modules.

HDOP ratings

Selection	HDOP thresholds
None	Triggering an event is disabled.
Excellent	HDOP is < or = 2.
Good	HDOP is > 2, but < or = 5.
Moderate	HDOP is > 5, but < or = 10.
Fair	HDOP is > 10, but < or = 20.
Poor	HDOP is > 20.
Custom	The lower threshold (that is, the threshold to be exceeded for an event to be triggered) depends on additional user defined settings.