![Sample our Geography journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5937/TOC-Subject-Sample-2021-Geography.jpg"})
Abstract
On 25 February 2013, the Satellite for Argos and AltiKa (SARAL) was launched from the Indian Sriharikota launch site. The AltiKa payload consisted of an altimeter and a radiometer. This paper describes the AltiKa radiometer. This instrument has been studied for several years by CNES, TAS-F, ASTRIUM-F and a set of science laboratories, and AltiKa is the first compact instrument embedding simultaneously the altimeter and radiometer functions. AltiKa radiometer is a dual frequency instrument working in K (23.8 GHz) and Ka band (37 GHz), it is based on the total power principle, with direct detection receivers. On-ground acceptance tests exhibited a very high level of performance: less than 0.2 dB has been estimated for both sensitivity and absolute accuracy in both frequencies. This paper focuses on the in-flight performances that have been observed since the launch. All the instrument observable characterizations are nominal, and in-flight sensitivity has been estimated lower than 0.2 K.
Acknowledgements
The work presented in this paper involved a large team who has been contributing through the AltiKa development, ground tests, and assessment phase analysis, including CNES, ISRO, CLS, TAS-F, and Astrium-F, for many years. The authors would also like to thank the Astrium-F AltiKa radiometric receivers team, in particular Franck Bayles and Marc Trier. The authors are grateful to Marie-Laure Frery and to others CLS investigators for the activities during development and CALVAL. CLS has also provided inputs and figures included in this paper.