ERS-1 radar altimeter in-flight performance

The ERS-1 radar altimeter, designed by Alenia Spazio S.p.A. under ESA contract, has been correctly operating in flight since July 1991. In this paper the results of the estimated height accuracy, derived from the 3-day repeat orbit data analyzed according to the collinear track method, are presented together with a short overview of the previous work done in the field of performance assessment. The results obtained are rather encouraging: values in the range 3.9 (best result achieved)-4.7 cm of total r.m.s. noise in height measurement, well below the ESA design requirement of 10 cm r.m.s. value.<>