GPS installations
Transcript of GPS installations
GPS-soil moisture measurements at SMAP ISST
xenon.colorado.edu/reflections/GPS_reflections/PBO_H2O.html
Eric Small, Geological Sciences, CU Boulder [email protected]
Kristine Larson, Aerospace Engineering, CU Boulder
John Braun (UCAR/COSMIC)
Funding and support
NSF-ATM, NASA UNAVCO
Use GPS multipath for L-band environmental sensing
“ignore” direct signal
Focus on the multipath
Detrended multipath signal
Soil moisture phase shift and frequency change Vegetation amplitude
Sensing Footprint SMAP ISST, Oklahoma
~1000 m2
9 test sites: Identical GPS and hydrology infrastructure and gravimetric and vegetation sampling
SMAP ISST-C
200 m
SMAP ISST 3 standard GPS (2.5 m) 1 raised GPS (6 m)
CS616 Five at 2.5 and 7.5 cm probes outside the pen
Estimates from GPS phase shift SMAP ISST Site D
Day of Year (2010)
Vegetation water content
2.5 cm 7.5 cm
GP
S P
HI
SMAP ISST Site D GPS phase shift and CS616 soil moisture
GPS PHI
Vol.
Soi
l Moi
stur
e (x
100)
7.5 cm 2.5 cm
GPS PHI
Vol.
Soi
l Moi
stur
e (x
100)
Correlation higher with soil moisture at 2.5 cm
Estimates from GPS reflector height SMAP ISST Site A
Day of Year (2010)
Vegetation water content
2.5 cm 7.5 cm
Ref
lect
or h
eigh
t (cm
)
SMAP ISST Site A GPS reflector height and CS616 soil moisture
GPS refl height (cm)
Vol.
Soi
l Moi
stur
e (x
100)
7.5 cm 2.5 cm
GPS refl height (cm)
Vol.
Soi
l Moi
stur
e (x
100)
Correlation higher with soil moisture at 2.5 cm
Comparison to gravimetric soil moisture
ISST Site A: 2010
For 2010, GSM from calibrated theta probe
2011 efforts at ISST
Soil moisture Comparison between GPS sites, including tall antenna Comparison to in situ probes and other methods
Vegetation Identify vegetation signal in multipath data
Sensing vegetation: winter wheat site