Miniaturized altimeter an innovative concept of miniaturized altimeter for constellations

Current dual frequency altimeter designs with a SAR mode such as the SRAL altimeter on-board Sentinel 3 have a mass of around 60 kg and a mode dependent power consumption of 90 to 100 Watts. These are typical figures for state-of-the-art instruments of this kind. However, for a potential constellation of altimeters aiming at improving temporal and spatial coverage, the mass and the power consumption need to be drastically reduced in order to be compatible with cost effective micro-satellites that can accommodate around 40/50kg & 50/100W for the whole altimetry payload (altimeter, radiometer, POD GNSS receiver and laser reflector). Starting from these objectives, the study of a miniaturized altimeter operating in Ku-band and C-band (for ionosphere delay correction) with a combined radiometer-altimeter antenna was performed by Thales Alenia Space in the frame of two ESA contracts (one for the instrument and electronics design and one for the antenna). This study is an extensive and innovative reconsideration of the altimeter design, taking into account all the technical and technological possibilities to achieve the challenge of keeping high altimetry performances while targeting a drastic reduction of volume, of mass, of telemetry rate and especially of power consumption (identified as the main issue), assuming an altimetry mission operational at the horizon of 2020.