Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering and Computer Science

First Advisor

Dennis Helder

Abstract

Earth observation satellite sensors can experience significant post-launch changes in their performance characteristics no matter how well they are calibrated prior to launch. These changes arise as a result of many factors, including rigors of the launch itself, the space environment in Earth orbit in general, the operating environment of the spacecraft, and the most significant of all being the aging of the sensors and their subsystems. Even well-built, stable and well characterized sensors require evaluation and monitoring of changes in the months immediately following launch but also over the lifetime of their operation [ 1]. The work presented in this thesis presents methods to characterize and radiometrically calibrate a hyperspectral sensor, the EO-1 Hyperion, by first performing cross calibration with a multispectral sensor, the Landsat 7 ETM+, and then absolute radiometric calibration using the reflectance based approach of vicarious calibration. The test site used for the characterization of the Hyperion sensor is a region inside the Libya 4 Pseudo Invariant Calibration Site (PICS). For cross calibration with ETM+, test sites were chosen across the globe. For absolute calibration, a standard test site, the South Dakota State University (SDSU) vegetated test site at Brookings, SD, was used to record the ground reflectance and atmospheric data. Hyperion data over the Libya 4 PIC site was first used to characterize the Hyperion sensor. A method implementing the RSR profiles of Landsat 7 ETM+ and reflectance data from the Hyperion sensor was used to simulate the ETM + multispectral data. Cross comparison between the simulated and actual measured ETM+ data provided results indicating agreement to within 4% between the two data sets for the wavelengths that fall within the six reflective ETM+ bands. The largest disagreement occurred for the band of wavelengths corresponding to ETM+ Band 2. These results only show the radiometric stability of the Hyperion sensor from a multispectral point of view. To extend this to absolute radiometric calibration, the reflectance based method of vicarious calibration was used to individually recalibrate the 196 calibrated bands of the Hyperion sensor. This study utilized the vegetated long-term standard calibration site near Brookings, South Dakota. The absolute radiometric gain of the Hyperion sensor has varied by less than +/-10% from the prelaunch values for the Visible and Near Infrared (VNIR) channels, and was within 20% for the Short Wave Infrared (SWIR) channels. The long term relative characterization of Hyperion was performed using a Pseudo Invariant Calibration Site (PICS) inside Libya, referred to as the Libya 4 PICS. The Libya 4 PICS has shown long term stability over the past 25 years at the sub 3% level. This characterization evaluated the long term stability of the Hyperion's absolute calibration over the past 11 years and showed it to be at the sub 3% level with no significant degradation over its lifetime. The long term relative calibration can be tied to the recent absolute calibration to extend the absolute knowledge back through the entire 11 year history of the Hyperion sensor.

Library of Congress Subject Headings

Detectors -- Calibration
Imaging systems -- Image quality
Remote sensing -- Equipment and supplies

Publisher

South Dakota State University

Download

Share

COinS
 

Rights Statement

In Copyright