Altika Instrument for Space Altimetry with Improved Performances and Ocean Sampling : Development Status and First Test Results

Altika instrument is a new class of altimeter allowing the compatibility of the altimetric payload (altimeter, radiometer, localisation system) with a micro-satellite. The key feature of the concept is the selection of the Ka-band for the single-frequency altimeter that avoids the need for a second frequency (necessary with Ku-band) to correct the ionosphere delay, and allows the same antenna to be shared by the altimeter and the radiometer to ease payload accommodation. This concept also improves the range measurement accuracy in a ratio of 3:1 thanks to a wider bandwidth and to a better pulse to pulse echo decorrelation. Development of AltiKa instrument (integrated altimeter and radiometer) has started in Thales Alenia Space in January 2005 for a FM delivery end of 2008 and a launch in 2009. This paper reminds instrument design, key technologies involved, altimeter and radiometer parameters, expected altimeter and radiometer performances, status of the instrument development and available test results.