Survey tab

Single Setup

• Settings (Gears): Common the the orientation options is the Settings button which provides short-cut access to the Configure (and optionally Total Station) options including:
  • General
  • Sets
  • Settings [RTS]
  • Search [RTS]
  • Average TS
• Occupy Point: Indicate the point the total station is set over. Methods include:
  • direct key-in (subject to point location rules)
  • Point List button
  • Map Pick button
  • Station-Offset button
    More Information

    

    1. Select a Centerline File
    2. Specify a Station, Offset and Elevation
       • If you click the "store to disk" icon, it will store the station and offset and after clicking OK in this dialog, you will be prompted for a description, and the next available point will automatically be assigned.
       • If you enter a station and offset that is equivalent to a known point, that point will populate in the Pt ID field.
       • If you enter a point in the Pt ID field, it will confirm to you the station and offset. In road work, this option can be used simply for confirmation of the correct station and offset for any entered point.
• Instr. Height: This is the height of the instrument from the point over which the instrument is set. The value uses Distance & Height guidelines.
• Backsight Point: Indicate the point number (or a point number using the same location options as discussed above) that will represent the backsight direction.

  Note: A backsight point ID is required, even if you choose to enter an azimuth or bearing only.

• Backsight Bearing or Azimuth: This displays the backsight direction when both points have coordinates using the specified angle format.

  Note: If the backsight point has no coordinates, then you must enter a backsight bearing or azimuth, which will be used to calculate the null (or zero coordinate) point ID.

• Backsight HT: This is the height of the backsight target from the point over which the target is set to the center of the target. The value uses Distance & Height guidelines.

  Note: The backsight target height will default to the previous backsight target height on future setups. The foresight target height is kept distinct and will default to previous foresight target heights but will not automatically match the backsight target height. If you prefer to survey by setting the prism pole to a fixed height for both backsights and foresights, be aware that you will have to put in two initial target heights: one for the first backsight in the backsight screen and one for the first foresight in the foresight screen, in order to get both "remembered" values established.

• Use Backsight Ht for Foresights: When enabled, this option will link the backsight height and the foresight height to accommodate the use of a single prism for both the backsight and foresight readings, rather than a fixed tripod at the backsight and pole for the foresight.
• Confirm NEZ: This option will display the full coordinates and description of both the occupy and backsight points.
• From Job: This will recall an occupied point, instrument height, backsight point and backsight orientation from another job. You should use this option when you are already set up, have previously taken a backsight and other measurements and wish to start a new job with the same backsight orientation and information. This is known as the Restore Occupation feature. Select your "source" raw file containing the last backsight used. The occupied point and backsight point will be added to the current job file automatically.
• Backsight: Continues to the Backsight screen.

Backsight

The backsight dialog has Setup and Results tabs showing the results of a measurement to the backsight.

• Set Angle Option List: Indicate the preferred method for setting the reference angle in backsight:
  • Set to Zero: This is the most commonly used option. A message is sent to the instrument to set it to zero, then the backsight is taken at a zero reference angle. Angles are then typically turned to the right from zero.
  • Set to BS Azimuth: In this scenario, the backsight direction in the instrument is set to the azimuth of the backsight. For example, if the backsight azimuth is 180°, then an angle to the right of 10° would read 190° from the instrument. This is useful in underground mine surveying because it ensures that the readings displayed by the total station always refer to true azimuth (e.g. "azimuth" surveying vs "set zero").
  • Set To: Allows the user to set a desired value.
  • Use Current: Uses whatever direction reading is already in the instrument.
• Turn to BS: With robotic total stations, you have the option to automatically turn to the backsight. This button will turn the instrument to the previously set backsight angle so that a Check Angle or Set Angle can be performed. Once you press ✅ to go back to the foresight screen, the instrument will automatically prompt if you want to return to the previous foresight position.
• Set Angle and Read: This button will set the horizontal angle and read the distance to the backsight. The program defaults "focus" to this button on the assumption that in most cases, you will be taking a distance measurement to the backsight.
• Set Angle: This button will only set the horizontal angle. If you are just backsighting an object or plumb bob without a measurement, you would choose Set Angle.
• Check Angle: This button will simply read the angle currently in the instrument and compare it to the reference angle (no distance comparisons are made).
• Check: This enables the surveyor to determine whether the instrument has drifted off the point. Based on what is presented here, the surveyor may decide to reset the BS angle, or to actually re-level and re-shoot the BS point. More commonly, you would do a Check Backsight after taking a large set of foresights. You may want to be sure that you haven't bumped the instrument or experienced settlement in the tripod legs.

Tapping ✅ completes the backsight setup and continues into the survey command.

Types of Total Station Backsights - Handling Missing Information

The SurvPC backsight procedure will allow last minute entry of the backsight coordinate values if none are found or will calculate the backsight coordinates using the azimuth and distance of the measurement. If both the Occupy and Backsight Points have coordinates (non-zero northings, eastings and elevations), the backsight azimuth is computed, and the coordinate values are not altered.

Known Occupy Point and Backsight Azimuth to Backsight Point of Unknown Coordinates

In the case that the coordinates of the Occupy Point are known and you shoot a backsight point of unknown coordinates, a backsight point will be calculated. Note that when a zero-coordinate backsight point is encountered, the program will prompt the user to Enter Coordinates or Use Azimuth. This prompt appears only when the Use Azimuth option has been selected. If you choose only to Set Angle, the backsight point will not be calculated, but is still a viable entry in the raw file. Some raw file processing programs make use of this backsight point with zero coordinates as a backsight azimuth reference. It is recommended that you use distinct new point IDs for all foresight points. Don't re-use a backsight point ID that serves as a "dummy" point to initiate the "set zero" backsight, unless you plan to re-use it for the same backsight again.

Remote Benchmark

In this orientation option, the elevation of one or more remote, but known, points are used to compute the elevation of the Occupied Point.

• Read: You have the option to transfer the elevation from a single benchmark by taking a reading on it, any number of times, in any face. You may also use multiple benchmark points, any number of times, in any face.
• Results: The readings taken on the benchmark(s) are reported in the Results dialog. All of the readings taken will determine an average instrument point elevation.
• Store: Click Store to update the instrument point elevation and store the point record into the raw data file.
• Confirm NEZ: This option will display the full coordinates and description of both the occupy (station) and remote points.

Robotics

The term Robotics applies to any supported motorized (one-man) total station.

• PowerSearch: For Leica, the PowerSearch option will conduct a fast search, typically less than 10 seconds. PowerSearch will find the prism regardless of the original direction the instrument is pointing.
• Search: This button will initiate a search to look for the prism or reflector. For Leica, Search initiates an ATR search. Pressing the Search or Quick-Lock buttons will lock the instrument to the prism and put the instrument back into tracking mode.
• Quick-Lock: Topcon has a search option called Quick-Lock which appears when configured for Topcon 800/8000 Remote using RC2. A Quick-Lock search will find the prism in less than 15 seconds.
• Standby: This button takes the instrument out of tracking mode. This is useful, for example, in allowing the user to set the prism pole down to drive a stake.
• Turn to Pt/Angle: This button opens an additional dialog that prompts you for a point or angle to turn to.
  More Information

  

  • Turn to Vertical: When enabled, the instrument will also turn to the vertical component of the point.
  • Search After Turn: When enabled, the instrument searches and attempts to lock on a prism after turning the angle.
  • Turn Left/Right 90, Turn 180: Common angle turns to minimize user entry when needed.
  • Change Face: Reverses the face of the instrument.
• Check BS (Backsight): This button will engage the instrument to automatically check the backsight and lead the user to the Backsight screen.

Occupation

Note: The visibility/usage of the Occupation method is controlled by the Configure - Show Advanced Backsight option.

The advanced Occupation command allows for multiple backsight points to be used to orient the instrument, conducting a least squares analysis on all measurements taken. It is sometimes referred to as the Multiple Backsight command.

In the example below, the goal is to better determine the location of Point 1 from several available backsights:

Although it is sufficient to simply backsight to point 4, from known occupied point 1, taking additional measurements to points 2 and 3 can lead to an "averaged" backsight and best fit orientation. Points 2-4 become Observations. Furthermore, if point 1 is not known, the position can be determined by the least squares calculations, similar to a Resection. Even if point 1 is known, if the calculated position is saved and not overwritten, then a redundant position for point 1 can be stored to the Raw File, leading to more precise calculation of point 1 by Network Least Squares methods.

In the above example, points 2 and points 3 can be considered to be towers and sighted for angle only measurements (points that might reside in an external Control File), while the measurement to point 4 would include both angle and distance.

Observations

Observations are the two or more backsight points you want to use to solve the Occupied Point location. When adding Observations, you can indicate which aspect(s) of the readings you'd like to use.

• Use Known E/N: When enabled, the horizontal coordinate of the point is used in the solution.
• Use Known Elev: When enabled, the vertical elevation of the point is used in the solution.
• HA: When enabled, the horizontal angle as recorded by the total station is used.
• ZE: When enabled, the zenith angle as recorded by the total station is used.
• SD: When enabled, the slope distance recorded by the total station is used.

As Observation points are specified, they are listed within the At: dialog box as shown below:

The goal of Observations is to load in advance all targets that will be used for the multiple backsight measurement. When distance measurements are involved, the prism offset can be entered distinctly for each measurement.

• Settings (gears): Permits customization of the types of information that is reported and the method in which information is gathered.
  More Information

  The Settings option includes the following settings:

  

  Solution

  • Collimation: Leads to a report on the collimation of the total station instrument provided that both direct and reverse measurements are taken to the same foresights.
  • Zero Index: This, when enabled, will allow the Zero Index errors computed and displayed in the Solution report.
  • Refraction Coefficient: This option should be selected only if the instrument itself does not automatically apply refraction correction in the reported readings.

  Sets Order

  • Sets Order: The two choices are to:
    1. take ALL backsight direct readings first followed by all backsight reverse readings (BD-BD/BR-BR), or,
    2. take the reverse reading following each backsight direct measurement (BD-BR/BD-BR).

  Measurement Accuracy

  • Horizontal Circle: Estimation of accuracy and is used in Least Squares calculations.
  • Vertical Circle: Estimation of accuracy and is used in Least Squares calculations.
  • Distance: Estimation of accuracy and is used in Least Squares calculations.
• Add: Use this option to include other backsight points in the solution.
• Edit: Use this option to re-configure the parameters associated with a selected backsight observation.
• Up/Down: Use these options to change the prompting order of the observation(s).
• Solve: Use this button to determine the current solution and review the results.
• Measure: This button will record the measurement(s) associated with a backsight observation.

General Process

1. When the entire list of targets has been entered, you then select the target and then tap Measure.
2. You will be prompted to turn to the target in direct face and take the reading. After the first measurement is taken, you are asked if you wish to complete the set to the rest of the points.
3. When all direct measurements are taken, you will be asked to continue the measurements in reverse face. If you do not wish to do both direct and reverse, you answer N and then continue. The program will announce, Set Complete. You will return to the list of targets and can then click ✅ to continue.
4. Here, you will either be led to the results screen showing the successful calculation, or it will report Unable to retrieve solution results. The computed results are shown by clicking Solve.

   Note: An added feature of the Advanced Occupation routine is the calculation of the occupied point coordinates. The degrees of freedom is the difference between the number of observations and the number of unknowns. The degrees of freedom increase if more redundant measurements are taken, such as reverse readings or multiple distance readings.

5. If you have taken both direct and reverse readings, the report includes data on the collimation of the instrument, provided that the collimation option is turned on within the Settings option.
6. When set to an actual field instrument, the Target dropdown appears. Prism Offsets can be changed for each total station measurement taken that includes a distance reading.
7. If measuring angle-only readings to objects such as radio towers and church steeples, you can stay in prism mode but just click off the SD (slope distance) component.
8. After cycling through all targets and being prompted for reverse readings (optional), you are returned to the target list. If you highlight a target and click Measure again, you are in effect launching another set of readings.
9. After completing a set, you can accumulate multiple readings which can vary from target to target, depending on whether you choose to skip certain target readings, do direct only, etc. Each direct and reverse measurement counts as a reading. You can turn all readings to a target on or off and by clicking Edit, you can turn any individual reading to a target on or off.
10. When the process is complete and you exit Advanced Occupation, the program adjusts the backsight orientation with the following prompt, after which it announces Operation Complete. Angle Set.
11. Within the Edit option, you can toggle off aspects of the reading. If you want to delete the entire entry in the list of targets, click Edit and click the Eraser icon at the top of the screen and click on All (lower right).

Note: For robotic total stations, the instrument will turn automatically to the direct and reverse positions for the selected targets, provided that within Configure - Sets, the Auto Turn, Auto Read and Robotic Set Order options are being used.