FAQ: Passive
Description cards for passive control points are available on the UGRF website. Navigate to the passive control section. Search for the specific passive point or CORS station to download its description card. The description includes coordinates, photos, and site information.
The methodology of observation, computation and adjustment of UGRF guarantees that the obtained positional accuracy of the geodetic points is better than:
- 20 mm in the horizontal and 30 mm in the vertical position for 1st Order.
- 30 mm horizontally and 40 mm vertical for 2nd Order.
- at the 95% confidence level.
First-order points: same accuracy as CORS station, suitable for high-accuracy geodetic applications.
Second-order points: Centimeter-level precision, typically used for general surveying tasks.
- 20 mm in the horizontal and 30 mm in the vertical position for 1st Order.
- 30 mm horizontally and 40 mm vertical for 2nd Order.
- at the 95% confidence level.
First-order points: same accuracy as CORS station, suitable for high-accuracy geodetic applications.
Second-order points: Centimeter-level precision, typically used for general surveying tasks.
The passive points have been processed from CORS stations. Their coordinates are available in UGRF Reference System.
The Arc1960 system was established with classical methods of surveying, which lacked the precision of modern GNSS technology. Using Arc1960 for the 1st and 2nd order points would lead to potential inconsistencies, as it was based on a local ellipsoid. Additionally, GNSS equipment relies on the WGS84 ellipsoid, a global reference system, making it incompatible with the local reference system of Arc1960.
This discrepancy could introduce errors in transformations between the two systems, affecting the accuracy and reliability of the coordinates. Therefore, UGRF focuses on using WGS84 and ITRF for better precision and consistency across the network.
Using ARC60 would degrade the quality of the points and process.
This discrepancy could introduce errors in transformations between the two systems, affecting the accuracy and reliability of the coordinates. Therefore, UGRF focuses on using WGS84 and ITRF for better precision and consistency across the network.
Using ARC60 would degrade the quality of the points and process.
The former control points, based on Arc1960, were outdated and insufficient for modern geodetic and GNSS applications. There were not enough existing points to get a properly dense geodetic network.
Report damaged or missing points to the UGRF support team through the email address mlhud.ugrf@gmail.com. Provide the control point’s name, location, and a brief description of the issue on ground.
The older passive control points were established in the Arc1960 coordinate system, which is based on outdated systems, leading to inaccuracies in modern geodetic applications. The UGRF network offers higher precision, better consistency with global standards, and compatibility with GNSS technologies, making it the preferred framework.