ESTAR TO SMOS DEVELOPMENT OF

INTERFEROMETRIC RADIOMETRY FOR REMOTE SENSING FROM SPACE

David M. Le Vine Goddard Space Flight Center

Greenbelt, MD 20771

Outline

ESTAR

• Short History– Description

– Plans for Space• Hydrostar

• SMOS

– Today: 2D-STAR

• Lessons Learned– RFI

– Scene Dependent Calibration

– Null feed backESTAR image of “Delmarva” Peninsula south of NASA’s Wallops Island Facility

ESTAR

• Hybrid– Real along track

– Synthetic across track

• Antenna Array– 8-element dipole stick

– H-pol only

– 5 sticks

– 7 baselines

• Objective– Demonstrate viability of aperture

synthesis for remote sensing

– Apply to SM and OS

ESTAR Hardware

Walnut Gulch Watershed

ESTAR Image TB vs Soil Moisture

ESTAR (Solid); PBMR (open)

Remote Sensing Campaigns

• Soil Moisture– Walnut Gulch Watershed

1991– Little Washita Watershed

1992, 1994– Southern Great Plains

Experiment: SGP- 97,-99 – Soil Moisture Experiment:

SMEX-02

• Ocean Salinity– Delaware Coastal Current

Experiment, 1993– Gulf Stream Experiment,

1999

HYDROSTARESTAR in Space: Proposed to First NASA ESSP Call

1. 2.

3.

4.

DeployedResolution < 30 km( 5.8 x 9.5 m array)

Deployment of Antenna (16 Slotted Waveguide Sticks)

2D-STAR

• Synthesis in two dimensions• Array of patch antennas• Multiple configurations • V and H-pol

2D-STAR Installed on NASA P3-B Aircraft

SMEX-03: Huntsville, AL

Above: Landsat, false color image of SMEX-03 site. Tennessee River at lower right.

Right: 2D-STAR image during SMEX-03; H-pol (top) and V-pol (bottom)

Lessons Learned

RFI is a problem even in the restricted band at 1.413 GHz

ESTAR image crossing the Chesapeake Bay near Richmond, Virginia showing effects of RFI

RFI in zero spacing channel

Noise Injection is Stable

• Used for ESTAR zero spacing

• Employed Basic Correlator

• Proved to be extremely stable

ESTAR TO SMOS DEVELOPMENT OF

INTERFEROMETRIC RADIOMETRY FOR REMOTE SENSING FROM SPACE

David M. Le Vine Goddard Space Flight Center

Greenbelt, MD 20771

C. Swift, T. Jackson, A. Tanner, C. Ruf, A. Griffis, J. Isham,P. Gaiser, M. Goodberlet , M. Haken, J. Fuchs, R. Aldridge, ProSensing Staff, M. Kao, J. Good

BACK UP

Scene Dependent Artifacts

• Reconstruction noise– G-matrix (anechoic chamber)– Antenna coupling

• Scene dependence– Gibbs phenomena

• ESTAR – Coupled with incidence angle– Scene-dependent Inverse “filter”