No abstract

Interferometric radiometry is a novel concept in remote sensing that is also presenting particular challenges for calibration methods. In this paper, we describe the calibration subsystem (CAS) developed for the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) interferometer of the Soil Moisture and Ocean Salinity (SMOS) satellite. CAS is important for the overall performance of the payload as it calibrates out the differences between the multiple receivers of MIRAS. SMOS is in the final phase of development and is due to launch in 2008.

No abstract

An L-band noise injection radiometer (NIR) has been designed and implemented by Helsinki University of Technology Laboratory of Space Technology for the SMOS (Soil Moisture and Ocean Salinity) mission of ESA [1]. The work is performed as a part of ESA's MIRAS Demonstrator Pilot Project-2 (MDPP-2) under a subcontract for EADS-CASA. Other partners in the MDPP-2 NIR project are Toikka Engineering Ltd. and Ylinen Electronics Ltd.NIR will work as a part of the MIRAS (Microwave Imaging Radiometer Using Aperture Synthesis) instrument. Its main purpose is (1) to provide precise measurement of the average brightness temperature scene for absolute calibration of the MIRAS image map and (2) to measure the noise temperature level of the internal active calibration source for individual receiver calibration. The performance of NIR is a decisive factor of the MIRAS performance.The challenge in the implemented, so-called blind correlation, method is the fact that there is additional noise in the correlated signal due to using the noise injection method. The main objective of this paper is to demonstrate the feasibility of this technique.

An airborne L-band two-dimensional interferometric radiometer by aperture synthesis, HUT-2D, is under development and construction at LST/HUT (Laboratory of Space Technology / Helsinki University of Technology) in co-operation with Ylinen Electronics Ltd. The instrument consists of 36 antenndreceiver elements and an FPGA-based digital correlator and it will be accommodated onboard the LST/HUT remote sensing aircraft, Short SC-7 Skyvan.