To review observation residuals and setup results

Use the observation residual information shown after a station setup plus or resection to review the quality of the observations and remove poor observations. A residual is the difference between the known position and the observed position of the backsight point(s).

NOTE –  

  • During a station setup plus or resection, no observations are stored to the job until you store the station setup.
  • A foresight point that does not yet exist in the database has null residuals in the Residuals screen.
  • During a resection, an asterisk (*) next to the point name in the Residuals screen indicates that the point name was not entered during the resection, and instead the observation was automatically matched by the Auto Resection routine in Trimble Access as a potential good fit.

To view the standard deviations of the observations for each point, tap Std Dev. The Std Dev softkey is available only after all rounds are complete.

To view the station setup or resection results, tap Results.

To store the station setup or resection, tap Results and then tap Store.

To view the details of an observation, select it and then tap Details. Resection observations are shown in the map in yellow, and the calculated station is shown as a solid yellow circle.

To observe more points, tap + Point.

To navigate to a point, tap + Point and then tap Navigate.

TIP – In a conventional only survey, when one measurement is completed, the Trimble Access software can provide navigation information for further points, and a Navigate softkey is available. Tap Navigate to navigate to another point. If connected to a GNSS receiver or using a controller with internal GPS, the Trimble Access software can provide navigation information for any point, and a Navigate softkey is available. Tap Navigate to navigate to another point.

To view the mean observed position and the individual observations for a point in the Point residuals screen, tap the point.

If the residuals for an observation are high, it may be better to disable the observation from the round.

To disable an observation, highlight it and then tap Disable.

Whenever you make a change in the Point residuals screen, the mean observations, residuals, and standard deviations are recalculated. If you have measured face 1 and face 2 observations to a point, when you disable the observation for one face, the corresponding observation on the opposite face is automatically disabled.

If you turn off some (but not all) of the observations to a backsight point in a resection, the solution for the resection is biased and there is different number of observations to each backsight point.

NOTE – If the current station setup has a single backsight only, the Disable softkey is not available for observations to the backsight. Observations to the backsight are used to orientate observations and cannot be deleted.

If you remove observations, the icon appears. If you skipped observations in a round, no icon appears.

The Point details screen shows a summary of the data associated with the measured point. This includes the point name, code, usage, target details, raw observation data, and measurement quality.

You can change the target height and prism constant for all observations to that point.

The content of the Usage group box differs depending on the workflow you are using:

  • Resection: For resection, the Usage group box provides controls for how a point is used in the resection calculation, including:

    • Observation use: Whether the point is used in the calculation. Select from:

      • Let resection decide: The software automatically determines if the point should be used, based on whether a point name was entered and the auto resection tolerances.

      • Enabled: The point is included in the calculation.

      • Disabled: The point is excluded from the calculation.

    • Auto resection point: This field is visible when Let resection decide is selected. It indicates if the software has automatically included or excluded the point from the solution.

    • Foresight only: Select this check box to store the point as a foresight observation. Foresight points do not contribute to the station setup calculation.

    • Used for: If you are viewing the residuals for a resection, you can change the components used in the calculation. This is available if you have selected the Compute station elevation option and the observed point has a 3D grid position.

      • H (2D): To use only the horizontal values for that point.

      • V (1D): To use only the vertical values for that point.

      • H,V (3D): To use both the horizontal and vertical values for that point.

  • Station setup plus: For station setup plus, the Usage group box contains only the Foresight only check box. Select this check box to store the point as a foresight observation. Foresight points do not contribute to the station setup calculation.