In 2004, Orion developed an innovative field station design that leveraged one enclosure, one wireless transceiver and one power source to house and support multiple GPS receiver-antenna pairs. The MultiPoint GPS station integrated a high-performance GPS antenna (fixed phase center, 27 dB pre-amp gain and low-elevation phase rolloff) with high-grade, low-attenuation coaxial cables to support remote GPS antenna placement. Stations were deployed at distances of up to 150 meters from the base enclosure to enable local, multiplexed monitoring clusters.
The MultiPoint system evolved partly from our experience with tall-building monitoring projects in 1999-2000 that coupled precise RTK GPS with strong motion accelerometry on the Century Plaza Towers in Los Angeles and the Pacific Gas and Electric Building in San Francisco, CA. The PG&E system used tens of meters of low-loss coaxial antenna cables to pass GPS RF signals to receivers located in the telecommunications center of the Tower's penthouse, showing the potential for extended cable runs. Once a reliable multiport, multiplexing wireless transceiver was identified, we redeveloped the system for remote operations.