Services · 02
Position & height control-network measurement and processing
Establishing, measuring and adjusting horizontal and vertical control networks, tied to the state coordinate and height systems and to the MONREF-97 reference frame.
What this is
A control network is a set of permanently monumented ground points whose positions are fixed, by relative measurement, in latitude and longitude or in x and y. It is the frame every later measurement hangs from: survey done without one is only ever self-consistent, and cannot be reconciled with anyone else’s work.
What you end up with
A coordinate and elevation catalogue tied into the national system — after which every survey done on that site agrees with every other, and with the state record.
- 01Horizontal network measurement and adjustment
- 02Class II and III levelling
- 03Polygonometric traverse networks
- 04Coordinate and elevation catalogues
- 05Permanent monument installation and protection
- 06Measurement reports and adjustment results
Where it is used
- The reference frame for a large construction site
- Bringing a mine site onto one coordinate system
- Control along road and railway alignments
- Renewing a town or city network
- Long-run deformation and settlement monitoring
Specifications
- National GPS reference frame
- MONREF-97
- Points in the national network
- 3 760
- Network established
- 1997–2013
- Annual crustal motion
- 3–4 cm
In detail
Where Mongolia’s network comes from
Mongolia’s geodetic network was built between 1936 and 1961 on polygons 88, 89 and 90 of the Soviet first-order triangulation, extending it with second-order chains and second, third and fourth-order networks. The origin coordinates were carried from the astronomical observatory at Pulkovo, then in Leningrad province and now St Petersburg, in the 1942 coordinate system on the Krasovsky reference ellipsoid.
Why a network has to be renewed
Regional network campaigns since 1999, in which the company has taken part at five or six stations, have established crustal motion of 3–4 cm a year to the east-southeast. An old catalogue, in other words, drifts. Any project of consequence needs to be tied to a present-day measurement rather than to a figure captured decades ago.
The network as it stands
MONREF-97, the GPS reference frame covering the aimag centres and larger settlements, was established in 1997–1998. Together with the principal and mapping GPS networks that cover the rest of the country, 3,760 points were established between 1997 and 2013.
Standards and norms
Work is delivered against Mongolian statute and construction norms.
- —Law on Geodesy and Cartography
- БНбД 11-08-06Geodetic work in construction
- БД 11-104-06Establishing permanent geodetic points and marks
Want to talk through this scope together?