Comparison of the spatial and radiometric resolution of ERS and Metop C-band radars

摘要

ERS-1/2 and Metop-A/B satellites carry a very similar radars operating at similar frequencies (5.3/5.255 GHz) and same polarization (VV). However, the radars on-board the satellites of these two missions differ in the pulse waveform, bandwidth and slightly in geometry. Moreover, the on-board and the on-ground processing is different. This paper investigates the spatial and radiometric resolution of these radars and the resolution enhancement between ERS (1991-2011) and Metop (2006-) missions. The spatial resolution assessment implies the computation and the comparison of the Spatial Response Function (SRF) of both systems. The SRF involves mainly the antenna gain pattern, the pulse waveform and the different on-board filtering stages. The radiometric resolution depends mainly on the signal to noise ratio (SNR) and the number of averaged independent samples (N). Furthermore, the correlation of the measurement samples in a resolution cell is computed to assess the independence assumption. The metric used to quantify the radiometric accuracy in scat-terometry is called K_p which is the relative standard deviation. A comparison of K_p parameter extracted from the nominal products of the two missions confirms the expected performance based on the SNR, N and correlation analysis.