1. DamageMap Prototype Using Real-time GPS Point Positioning
Hudnut, K. W., E. Safak, A. Borsa,
J. Langbein, K. Stark, D. Barseghian,
I. Stubailo, M. Kohler, P. Davis
Strong Motion Forum
EERI Annual Conference
Universal City, California 9 February 2007

2. foundation for real-time structural damage detection and response
GPS network infra-
structure forms the
foundation for real-time
structural damage
detection and response
System design & performance tests
Telemetry upgrades
Algorithm develop-
ment and tests
Implementation

3. Sensor technology GPS Gyro Accelerometer position displacement
velocity
acceleration
Frequency response

4. Proper transducers for DamageMap: accelerometers, GPS, gyros, tiltmeters
Langbein & Bock (2003)
Courtesy
of John
Langbein
(USGS)

5. GPS high-rate (1 Hz) analysis
Larson, Billich and Choi - see Ji et al.
Sidereal filtering (Larson, Choi)
Stacking (Billich)
Significant reduction in long-period drift
Compares well now with our static GPS displacements

6. Doubly-integrated seismic vs
Doubly-integrated seismic vs. GPS for Parkfield 2004 PHOB)
Raw GPS solution in blue
Filtered GPS in green
Seismic in red (Boore)
These show results prior to
final GPS analysis step of
stacking, shown previously

7. Erdal Safak (USGS)

8. Factor Building at UCLA Prototype for DamageMap
PI’s Erdal Safak, Monical Kohler and Paul Davis

9. Viper
Shuttle
Ashtech Z-12
NavCom rx’s

10. Initial GPS Data from Factor Building
Y RMSE = 5 cm
X RMSE = 9 cm
100 times better than normal GPS accuracy (SPS now near PPS performance of % w/ S/A off)
Available worldwide $1400/yr.

11. Real-time StarFire
Post-processed (TRACK)

13. Multi-taper power spectra (TRACK)
Multipath:
- red noise
- peaks from large
individual reflectors
5.5 hrs.
2 seconds

14. Slider tests GPS antenna moved along a track
Precisely recorded displacements and times
Real-time and precisely post-processed data

17. Gyros and MEMS with GPS
Stable gyro technology is costly but MEMS-gyro and FOG are lower cost and approaching accuracy
Barbour & Schmidt, 1998

18. Summary
Future earthquake monitoring systems will allow faster and better response
Tools support rapid and accurate decision-making by emergency responders
DamageMap concept
Measure structural damage directly - don’t need to know anything else - ‘quick & easy’ and simple, robust reliable design
obtain more accurate displacement observations
new instrumentation for dynamic and static displacement address deficiencies due to double-integration of accelerometer records
R&D effort for DamageMap instrumentation - we completed an initial demonstration of PPP GPS using USGS Venture Capital and ANSS start-up funds, but R&D program funding support has not been maintained and major funding and long-term support for implementation has not yet been identified
We are far from being prepared for a Big One in California - it is time to “step it up” - use new technology, fix problems ahead of time

19. Ken Hudnut
Dept. of the Interior - U. S. Geological Survey
525 South Wilson Ave.
Pasadena, CA