Estimation of modulation transfer function for the Vietnamese satellite VNREDSat-1 by using the permanent test site

Modulation transfer function (MTF) is the magnitude response of an optical system to sinusoids of different spatial frequencies, it is defined as the normalization of the Fourier transform of the Point Spread Function (PSF). MTF is not only an important factor in evaluating image quality but also an indicator to estimate the performance of payload on optical remote sensing satellite, especially for high spatial resolution small satellites. The data used in the analysis are from VNREDSat-1 launched on May 7, 2013, and they are in 2.5-meter ground sample distance (GSD) in the panchromatic band. The classical slant-edge method for permanent test site is used to estimate MTF, thereby evaluating the VNREDSat-1 performance. The archived results proved that image quality has been ensured during the designed life of 5 years; moreover, those are also the basis for Vietnam to finalize regulations in terms of validation and calibration for optical remote sensing satellite since it has its own test site. © 2021 Space Research Institute of the Russian Academy of Sciences. All rights reserved.