WISCORS Information |
Benefits of a CORS network |
The Wisconsin Department of Transportation (WisDOT) Geodetic Surveys Unit is developing a statewide Global Navigation Satellite System (GNSS) reference station network, called the Wisconsin Continuously Operating Reference Stations (WISCORS) Network. This network consists of over 80 permanent GNSS reference stations that can provide GNSS corrections to mobile users in real-time. Mobile users properly equipped to take advantage of these GNSS corrections can position in the field to the 2 centimeter accuracy level in real-time.
The mission of the WisDOT Geodetic Surveys Unit is to apply state-of-the art methods of precise positioning and advanced geodetic techniques to establish and maintain the horizontal and vertical geodetic control infrastructure across the state of Wisconsin. A principal objective in that mission is the establishment and operation of a permanent GNSS CORS network in Wisconsin.
- CORS are established at an approximate 50 kilometer spacing across the state of Wisconsin.
- Network software is necessary to configure and monitor the quality of data from the reference stations, compute corrections, and output the corrections in real-time to mobile users in the field.
- Full GNSS-capability: WISCORS reference stations track both the United States NAVSTAR Global Positioning System (GPS) and the Russian Federation (GLONASS) global navigation satellite systems.
- WISCORS observation data is archived and available online via the WISCORS Web Server for users who desire to post-process field collected data.
Benefits of a CORS Network
- Eliminates the need and cost for another receiver to act as a base.
- Eliminates the resource time associated with equipment setup at the base site.
- Greatly enhances consistency of coordinate determination.
- Reduces the need for permanent monumentation on a local level.
- Reliability and redundancy is ensured.
The WisDOT Geodetic Surveys Unit is partnered with the federal government (NOAA-NGS), state and local government agencies, and multiple educational institutions in the development, implementation and operation of the system.
Through cooperative agreements, host site partners have agreed to contribute facilities, power, and access to high-speed internet service. WisDOT has supplied nearly all of the GNSS hardware, all of the materials and supplies needed to construct the CORS monuments, all of the information technology (IT) components and network software needed to operate the system.
The WISCORS field components installed at a host site partner facility include:
- Concrete pillar monument or building mount monument
- GNSS receiver and GNSS antenna
- Coaxial cable, plastic conduit, and lightning suppressor
- Enclosure boxes to house equipment and electrical components
The current design of the WISCORS concrete pillar monument features a 36 inch diameter by 12 foot deep concrete foundation, with a top concrete obelisk that extends 8 feet above the foundation. The concrete obelisk is 20 inches square at the bottom and 12 inches square at the top, with a decorative inset panel on each of the four sides. The WISCORS building mount monument is constructed of welded stainless steel tubing and is anchored at the top of an exterior wall of a concrete or masonry structure. A standard threaded leveling adapter is utilized for both the concrete pillar and building mount monument.
The CORS construction process includes the installation of a continuous 1.5 inch plastic conduit, which is used to carry the coaxial cable from the antenna atop the monument to a lightning suppressor. From the lightning suppressor, the coaxial cable is carried in conduit to the electrical enclosure box, which contains the GNSS receiver and a battery backup unit. A dedicated electrical outlet is also installed inside the enclosure box to provide power for the GNSS receiver. Metal tubing conduit can be used to carry an Ethernet cable from the GNSS receiver to the high speed internet access point at the facility.
WISCORS concrete pillar monument at Kewaunee, Wis.
WISCORS building mount monument at Winneconne, Wis.
GNSS receiver and battery backup unit installed at a WISCORS host site facility.