GPS antenna monuments and mounts supported by UNAVCO: Options and Effectiveness

Many different monumentation types and antenna mounts have been used in UNAVCO-supported projects for campaign, semi-permanent and long-term continuous GPS sites. We describe nine monuments and mounts currently in popular use in UNAVCO-supported projects as options to the greater scientific community, and compare results from these monuments and mounts for data quality. The designs range in height from 0 to 3 meters; substrates into which they are installed include soil, bedrock, and concrete; and costs range from approximately 30 to 15000. In many places outside the US, logistical, economical, and material restraints make installation of deep- and shallow-drilled braced monuments at best difficult and at worst impossible. Is a 1000 deep-drilled braced monument significantly better than a 150 stainless steel mast set into bedrock? We make a first order comparison of commonly used monument and mount types using existing site data from the science community. Preliminary results suggest that the effect of monument type on multipath is outweighed by the effect of the site environment.