AN: G41B-03
TI: Estimates of GPS and Monument Noise From the Bay 
    Area Regional Deformation (BARD) Permanent Array
AU: N E King
AF: USGS, Menlo Park, CA 94025
EM: nking@isdmnl.wr.usgs.gov
AU: H Johnson
EM: johnson@jota.ucsd.edu
AU: W H Prescott
AF: USGS, Menlo Park, CA, 94025
EM: wprescott@isdmnl.wr.usgs.gov
AU: M H Murray
EM: mmurray@cotopaxi.Stanford.EDU
AU: J L Svarc
AF: USGS, Menlo Park, CA 94025
EM: jsvarc@isdmnl.wr.usgs.gov
AU: R Clymer
EM: rich@seismo.berkeley.edu
AU: B Romanowicz
EM: barbara@seismo.berkeley.edu
AB:   
      
    A permanent GPS array in northern California provides a
    high-quality geodetic profile from the Farallon Islands
    to the Sierra Nevada. This profile spans the San Andreas,
    Hayward, and Calaveras faults. The U. S. Geological
    Survey (USGS), the University of California at Berkeley
    (UCB), Stanford University, and Trimble Navigation
    established the array in 1993-1994. There are two
    different monument designs; USGS monuments are four
    stainless steel rods driven about 12 m into alluvium
    while UC Berkeley monuments are stainless steel rods set
    into a drill hole in rock. In 1996 USGS began to use the
    new choke ring antennas, allowing us to estimate how this
    antenna design affects GPS noise. Sufficient data now
    exists to estimate the magnitude of white, $1/f$, and
    $1/f^2$ noise, discriminate between error models, and
    begin to evaluate the contributions of geologic setting,
    monument design, and antenna type to the error. Estimates
    of white noise are typically 2 to 3 mm in the horizontal
    and about 10 mm in the vertical. Estimates of monument
    noise, using the random-walk ($1/f^2$) model, are
    typically 2 to 5 $\rm$ mm/yr$^{1/2}$.  
SC: G
DE: 1209
DE: 8155
DE: 1294
MN: Fall Meeting 1996