An Evaluation of the High Accuracy Reference Network relative to the Continuously Operating Reference System

The establishment of the Continuously Operating Reference Station (CORS) network has provided the user community with a set of vastly improved positional coordinates. Data from these CORS sites are accessible through the INTERNET and, with the proper procedures, can be used in conjunction with GPS observations to densify the High Accuracy Reference Network (HARN). A nationwide A-Order GPS survey has recently been observed and analyzed. This survey provides ties between the CORS network and the HARN throughout the conterminous United States. In this paper, I will discuss the magnitude of the horizontal positional discrepancies thus found between CORS and HARN sites. In addition, I will discuss the methods that were used to reduce most of the larger discrepancies. Finally, I will discuss the known positional discrepancies that currently remain between CORS and HARN sites.