Edit GNSS Vector Values¶
Use this dialog to specify the estimated standard deviations for transformed directions, zenith distances, and distances. These values are used for weighting the observations.
Where to Find the Dialog¶
Select the icon for Gemini Terrain Settings..., then choose Land Surveying: Instruments under Common Settings.
Description¶
You can also enter estimated parameters for an area in a given coordinate system or datum for the selected GNSS receiver. This information is used to correct transformed observations in the calculations.
Number¶
Internal numbering system for the GNSS receiver.
If you need to enter the receiver number using the Replace function in the list window, use the format 9/1, 9/2, ..., 9/9.
Name¶
Designation of the GNSS receiver.
Standard Deviation¶
- Constant part: Distance-independent standard deviation, specified in gon.
- Distance-dependent part: Distance-dependent standard deviation, specified in gon/km.
- Centering: Estimated centering accuracy, specified in meters.
Total Standard Deviation (Std)¶
Std² = (StdC + D × StdA)² + (StdS)² for distance.
Std² = (StdC + D × StdA)² + (StdS/D)² for direction.
Std² = StdC² + (D × StdA)² + (StdS/D)² for zenith distance.
Here, StdC and StdA are the constant and distance-dependent parts of the observation, respectively, StdS is the centering accuracy, and D is the distance. This total standard deviation is transferred to the observation unless you have entered other values or requested an updated standard deviation.
Note
If you use the formulas to calculate the standard deviation for a given observation, pay attention to the units.
Alternative 1: Convert gon to radians (PI/200) before entering the values in the formula, i.e., for the constant and distance-dependent parameters. Finally, convert the result back from radians to gon (200/PI).
Alternative 2: Convert the centering part (StdS/D) to gon (200/PI). Then all terms will have the unit gon. This gives the same result as alternative 1.
Example
Values for standard deviation calculation:
| Observation Type | Constant Part | Distance-Dependent Part | Centering |
|---|---|---|---|
| Direction Measurement | 0.00013 gon | 0.0000 gon/km | 0.003 m |
| Zenith Distance | 0.00026 gon | 0.0000 gon/km | 0.003 m |
| Distance Measurement | 0.001 m | 0.002 m/km | 0.003 m |