GNSS in Remote Sensing and Earth Science

Transcription

1 GNSS in Remote Sensing and Earth Science James L Garrison School of Aeronau:cs and Astronau:cs Division of Environmental and Ecological Engineering School of Electrical and Computer Engineering (courtesy) ION- US Panel at the 4th China Satellite Naviga:on Conference (CSNC 2013)

2 GNSS in Remote Sensing Basic GNSS and its complica:ons Atmosphere/Ionosphere propaga:on Atmospheric Bending Reflectometry Conclusions

3 Basic GNSS Naviga:on τ 2 τ 3 τ 4 τ 1 4+ Observa:ons cτ 1 = cτ 2 = cτ 3 = cτ 4 = 4 Unknowns (X X 1 ) 2 + (Y Y 1 ) 2 + (Z Z 1 ) 2 +ct b (X X 2 ) 2 + (Y Y 2 ) 2 + (Z Z 2 ) 2 +ct b (X X 3 ) 2 + (Y Y 3 ) 2 + (Z Z 3 ) 2 +ct b (X X 4 ) 2 + (Y Y 4 ) 2 + (Z Z 4 ) 2 +ct b

4 Complica:ons τ 2 τ 3 τ 4 Variable Propaga:on speed τ 1 Atmospheric bending Mul:path

5 One person s Noise is another one s Signal

6 Complica:ons τ 2 τ 3 τ 4 Variable Propaga1on speed τ 1 Atmospheric bending Mul:path

7 Precipitable Water Vapor (PWV) [hzp:// Global Ionosphere Maps [CODE: hzp://aiuws.unibe.ch/ionosphere/ ]

8 Ionospheric Observa:ons of Seismic Events satellite IEC = N ( l) dl receiver e GNSS Network IEC(t) Time

9 GEONET GPS Ground mo:on (GPS) Tsunami Wave March 11, 2011 Earthquake and Tsunami [Yang et al, 2011]

10 March 11, 2011 Earthquake and Tsunami [Yang et al, 2011]

11 Complica:ons τ 2 τ 3 τ 4 Variable Propaga:on speed τ 1 Atmospheric bending Mul:path

12 Airborne Radio- occulta:on PREDICT Campaign Hurricane [Murphy, et al., 2012]

13 Complica:ons τ 2 τ 3 τ 4 Variable Propaga:on speed τ 1 Atmospheric bending Mul1path

14 Ocean Reflectometry Fundamental Physics: Rougher surface = larger distribution in path delays Receiver glistening zone glistening zone

15 Ocean Roughness/Wind Speed This phenomenon can be observed in visible light at sunset: (water is calm inside the red ellipse) (From Chapron and Ruffini, GNSS- R workshop, Barcelona. Photo taken at Le Conquet, BriZany)

16 Ocean Roughness/Wind Speed Airborne measurements: Example Waveform Hurricane Dennis, 2005 [Garrison, et al, 2002 ] [Katzberg, et al, 2006]

17 Ocean Roughness/Wind Speed Ocean roughness correc:on of radiometry (Ocean salinity measurements) [S. Katzberg, SCSU] [Garrison, et al, 2011]

18 Soil Moisture Reflectometry P T Vegeta:on canopy P R α ΓP T Soil T g

19 GNSS- R Soil Moisture Sensing Before Rain Aker Rain [Masters, et al. 2004, Katzberg, et al. 2006] 3-19

20 GNSS- R Soil Moisture Soil Moisture signature in geode:c sta:ons [Larson, et al 2008, 2008a]

21 GNSS- R Soil Moisture Ongoing work (Garrison, et al): Long- term calibra:on of GNSS reflectometry vs. in- situ soil moisture, snow & ice Agricultural Center for Research and Educa:on (ACRE)

22 Save the Date October 10-12, 2012 Workshop on Reflectometry using GNSS and Other Signals of Opportunity (GNSS+R) PURDUE UNIVERSITY, WEST LAFAYETTE, INDIANA, USA The purpose of this workshop is to provide a forum for exchange of technical and scientific information between researchers working in various applications and methods of remote sensing using reflectometry with signals of opportunity. For more information visit: GNSS+R 2014 Date and Loca1on to be Announced!

23 Conclusions GNSS signals designed for posi1oning Varia:ons in the Earth s atmosphere, ionosphere, ocean and land mass introduce many complica1ons Fixing these complica:ons was (and is) a large part of the research that made GNSS work These errors oken present new and useful measurements of the underlying geophysical processes

24 Conclusions GNSS remote sensing provides valuable informa:on for many applica:ons: Seismic Hazards (tsunami warning) Weather (water vapor) Tropical storms (water vapor change, wind speed) Agricultural produc:on (soil moisture) Climate change (soil moisture, sea ice)

25 References Garrison, J. L., Komjathy, A., Zavorotny, V.U., and Katzberg, S.J., Wind Speed Measurement from Forward ScaZered GPS Signals, IEEE Transac:ons on Geoscience and Remote Sensing, Vol. 40, No. 1, Jan. 2002, pp Garrison, J.L., Voo, J.K., Yueh, S.H., Grant, M.S., Fore, A.G., and Haase, J.S., Es:ma:on of Sea Surface Roughness Effects in Microwave Radiometric Measurements of Salinity Using Reflected Global Naviga:on Satellite System (GNSS- R) Signals, IEEE Geoscience and Remote Sensing Le4ers, Vol. 8, No. 9, p , Nov Katzberg, S. J., O. Torres, and G. Ganoe (2006), Calibra:on of reflected GPS for tropical storm wind speed retrievals, Geophys. Res. Le4., 33, L18602, doi: /2006gl Katzberg, S.J., Torres, O., Grant, M.S., Masters, D., U:lizing calibrated GPS reflected signals to es:mate soil reflec:vity and dielectric constant: Results from SMEX02, Remote Sensing of Environment, Vol. 100, Issue 1, 15 January 2006, Pages Larson, K.M., Small, E.E., Gutmann, E.D., Bilich, A.L., Braun, J.J., Zavorotny, V.U., Use of GPS receivers as a soil moisture network for water cycle studies. Geophys. Res. Le4., Vol., 35, Issue 24, Dec DOI: /2008GL Larson, K.M., Small, E.E., Gutmann, E.D., Bilich, A.L., Axelrad, P., Braun, J., Using GPS mul:path to measure soil moisture fluctua:ons: ini:al results, GPS Solu?ons, Vol. 12, Issue 3, pp , DOI: /s

26 References Masters, D., Axelrad, P., Katzberg, S.J., Ini:al results of land- reflected GPS bista:c radar measurements in SMEX02, Remote Sensing of Environment, Vol. 92, Issue 4, 30 Sept. 2004, Pages Murphy, B.J., Haase, J.S., Muradyan, P., and Garrison, J.L., Moisture variability in a developing cyclone as measured by airborne GPS radio occulta:on, 30th Conference on Hurricanes and Tropical Meteorology, April 2012, Ponte Vedra Beach, Florida Yang, Y., Garrison, J. L., Galvan, D. A., Komjathy, A., and Mannucci, A. J., Analyses and Classifica:ons of Traveling Ionospheric Disturbances from the 2011 Japan Tohoku Earthquake/Tsunami Event, Abstract NH54A- 08 presented at 2011 Fall Mee:ng, AGU, San Francisco, Calif., 5-9 Dec., 2011.