From: Boudewijn Ambrosius and Danny van Loon (DEOS/DUT) Subject: [IGSMAIL-1636] New station WSRT at Westerbork, the Netherlands Date: Thu, 26 Jun 1997 9:02:11 PDT ****************************************************************************** IGS Electronic Mail Thu Jun 26 9:02:11 PDT 1997 Message Number 1636 ****************************************************************************** Author: Boudewijn Ambrosius and Danny van Loon (DEOS/DUT) Subject: New station WSRT at Westerbork, the Netherlands Dear colleagues, On June 26, 1997, a new station has become operational in Westerbork, the Netherlands. It is situated at the premisis of the 'Westerbork Synthesis Radio Telescope' (WSRT), which falls under the responsibility of the ASTRON organization in the Netherlands. We have decided to use the WSRT acronym as the 4-character ID of the station. It will be operated by the 'Delft Institute for Earth Oriented Space Research' (DEOS) at 'Delft University of Technology' (DUT) in the Netherlands, which is also already acting as the operational center for KOSG, IRKT and MDVO. The new station WSRT has been established because DUT has decided to close down its facility in Kootwijk (KOSG), probably next year. Of course we regret this decision, but it is necessary for reasons of cost reductions and to enhance the efficiency of the organization. KOSG has been active as a GPS station since the early days of IGS and it already participated in the GIG-91 campaign. Its reliable and successful operations were the main reasons why it received the status of 'core' station in the global IGS network. We would like to transfer this role to the new WSRT station which is only 100 km away from Kootwijk. In order to ensure a smooth transition, we will try to keep both stations running in parallel for at least one full year. Therefore, we would like to call on all the IGS data analysis centers to start including WSRT in their analyses immediatly. From our part, we will invest a strong effort to determine an accurate tie between KOSG and WSRT. This will include mobile SLR colocations at both stations and possibly special measurement campaigns with Water Vapor Radiometers, to improve the vertical connection. In fact, WSRT has the potential to become even a better station than KOSG. One of the reasons is that the external frequency standard for WSRT is a Hydrogen Maser, whereas KOSG relies on a Rubidium clock. In addition, the radio telescope, on which grounds the new station is hosted, will also start to make VLBI observations in the near future, thus providing an direct colocation with another important space-geodetic technique. Furthermore, regular colocations with mobile SLR are planned and the station will also be equipped with a gravimetric platform. It will be designated the status of principal geodetic reference station for the Netherlands, as soon as all techniques are operational, and so it will take over the role of Koowtijk. The antenna of the GPS system at WSRT is mounted on a 18 m long mast, standing on a concrete platform which is firmly embedded in a geologically stable sand layer. The vertical position of the antenna is stabilized with an Invar-wire/spring system, similar to the construction used in Metsahovi (METS). The GPS system consists of an Allan Osborne TurboRogue SNR-12 RM receiver (ser.no. 209) connected to a Dorne Margolin T chokering antenna (ser. no. 273). As already mentioned, the external frequency standard is provided by a Hydrogen Maser, which is also the primary reference for the radio astronomical observations at this site. The approximate coordinates of the station are (in WGS'84): X = 3828739 m Y = 443305 m Z = 5064887 m and the height of the antenna reference point (bottom of chokering) above the geodetic marker on top of the mast is 379.5 mm. A station log sheet with complete information will be submitted at the end of next week. As of June 26, 1997 (DOY 177), the data will be submitted to the European Regional Data Center at IfAG in Germany, which will take care of further distribution to the IGS community. Test data which have been collected since May 2, 1997, will be available on request. Requests should be sent to: Boudewijn.Ambrosius@lr.tudelft.nl. Last but not least we would like to thank all the organizations and individuals in the Netherlands who have worked hard to realize this new high-quality station. We hope it will provide a valuable contribution to the IGS and that it will last for a very long time. Boudewijn and Danny [Mailed From: Boudewijn Ambrosius ]