Trimble, a Sunnyvale, Calif., developer of global positioning system (GPS) technology, announced that the Institute of Geological and Nuclear Sciences Ltd. (GNS), in New Zealand, has purchased 40 Trimble NetRS reference station receivers to expand continuous global positioning system (CGPS) networks across the North and South Islands of New Zealand. In 2001, GNS bought 20 Trimble 5700 continuously operating reference station receivers to create a backbone CGPS network for Land Information New Zealand (LINZ) in the North Island of New Zealand and for use in GPS campaign surveys. The new NetRS receivers will be used to expand the network to the South Island. The GPS information is used to monitor plate tectonic movements in New Zealand related to the Australia-Pacific Plate Boundary as well as volcanic activity in the central North Island.