National Reference Frame

The NRF provides the connection between national geodetic and vertical datums, and international reference systems.

This page summarises the main characteristics of the network.

Purpose

To enable the link between official geodetic and vertical datums and international reference systems to be determined and monitored.

Density

  • At least one geodetic datum reference mark (GDRM) on the stable part of each tectonic plate (Pacific, Australian, Antarctic)
  • Vertical datum reference mark (VDRM) to be co-located with each GDRM

Accuracy

  • Order: 0
  • Tier: Horiz A (0.05 m), Vert A (0.05 m)
  • Class: Horiz II (0.003 m, 3x10-8m/m), Vert II (0.003 m, 3x10-8m/m)
  • Class evaluation radius: all NRF marks

Mark characteristics

  • GDRM normally continuous GNSS
  • VDRM normally absolute gravity
  • May co-locate with other observation systems (VLBI, DORIS)

Location

  • To enable GNSS collection (GDRM)
  • To enable absolute gravity collection (VDRM)

Mark access

  • Data available from LINZ website
  • No physical access to mark