L1

The L1 project was to design, build, and install inexpensive combined units consisting of L1-only Canadian Marconi Corp. (CMC) Allstar receivers with Freewave radios, along with custom-built GPS L1-only antenna and groundplane units, at field site with power systems and telemetry, for high-risk geo-hazardeous areas such as volcanoes and other locations. Post-processing required also using normal dual+frequency L1+L2 GPS receiver data at several sites ususally within a few 10's of kilometers in order to obtain position accuracy of a centimeter or less at the L1 sites.

Initial development began in late 1997 and L1 sites were installed starting in Oct 1998. Most sites ran until 2005-2008 with a few still running in the Galapagos until replaced in the summer of 2010. Many of the original L1 sites were replaced with dual+frequency L1+L2 GPS instrumentation, such as the Trimble NetRS, as the cost of high-precison dual-frequency receivers decreased over time.

Please see L1 sites using the Data Archive Interface.

Last modified: 2026-05-28  09:22:23  America/Denver