Semi-Permanent GPS Station Design for High Resolution, High Accuracy Strain Monitoring in the Basin and Range Abstract

abstract

  • The Basin and Range (B&R) is an example of a tectonic province which is characterized by slow secular deformations of a spatial complexity that can only be fully revealed by sufficiently high resolution (~20 km) geodetic measurements over a large area (10^6 km^2). Furthermore, an important requirement for unbiased estimation of secular strain is to adequately sample seasonal variation in station position, which implies a required temporal resolution of ~0.1 yr. It is therefore likely that, in provinces such as the B&R, the temporal resolution of <<0.01 yr provided by continuous GPS can be relaxed in favor of providing enhanced spatial resolution. For example, if each GPS receiver shares its tracking time between a pair of stations every few weeks, the spatial resolution can be doubled, at the acceptable cost of decreasing the temporal resolution. Apart from increasing the spatial resolution of secular signals, this strategy also creates a possible opportunity to capture co-seismic signals with high spatial resolution, by providing a dense GPS network with accurate pre-seismic coordinates in the earthquake region. The response to potential earthquakes would be rapid and vastly simplified.
    Here I present the design of a recently installed network of 30 stations serviced by 17 receivers in the B&R province (funded by the DOE Geothermal Program). The GPS stations are entirely mobile except for a rock-bolt monument, which has such low enviromental impact that permitting process is radically simplified (or not deemed necessary). Key design features include ability to rapidly redeploy the GPS systems, the requirement that the antenna phase center be repeatable to << 1 mm, and that theft or vandalism is deterred. A potential side-benefit of such a design is reduced multipathing due to the lack of large metallic structures around and under the antenna, such as the reinforced monuments and chain link fences often associated with permanent GPS stations. Also, such a design allows for the purchase of 2 or 3 GPS stations sets (serving 4-6 stations) for the price of just one permanent GPS station.

publication date

  • 2004

presented at event