Analysis of an Improved Temperature Management Concept for SAR System Calibration Transponders

Abstract:
For the radiometric calibration of spaceborne synthetic aperture radar systems, active targets with known backscatter, so called transponders, are used. These serve as an external absolute reference, and the quality of the derived calibration parameters depends on the quality of the deployed transponders. Due to the temperature dependent behavior of the implemented active radio frequency components the transponder radar cross section is sensitive to the temperature of the components. This effect requires the implementation of a reliable and precise temperature management system to stabilize the temperature of the radio frequency components to a constant value under all relevant environmental conditions. In order to fulfill the increasing requirements for future transponders towards radiometric accuracy temperature control concepts must be further developed. For this purpose, an existing temperature management systems is analyzed and a control design concept is investigated. Finally the functionality of the implemented temperature management system is verified with measurements of the complete transponder system in a climatic chamber.