On-orbit spatial calibration performance of Landsat 8 and 9 thermal infrared sensors

Abstract

The Landsat program has consistently provided high quality Earth imagery for over five decades. The Thermal Infrared Sensor (TIRS) on Landsat 8 and on Landsat 9, launched in Feb 2013 and Sept 2021 respectively, are nearly identical 2-band (10.9 and 12 micron) push-broom sensors extending the legacy of Landsat thermal measurements. Both Landsat 8 TIRS and Landsat 9 TIRS were built at NASA Goddard Space Flight Center. The pre-launch testing of both TIRS characterized the radiometric, spectral and spatial performance using essentially the same calibration ground support equipment system as well as analysis methodologies and techniques. Landsat 9 TIRS benefited from lessons learned from the original Landsat 8 TIRS so overall has better performance. Once on-orbit, it is challenging to evaluate the spatial calibration performance of a sensor. One technique is to use ocean coastlines in desert regions as a high contrast edge target. This paper focuses on the spatial characterization assessment of both sensors while on-orbit in terms of edge spread function, point spread function and modulation transfer function. It is shown that both Landsat 8 TIRS and Landsat 9 TIRS demonstrate consistent spatial performance over their respective mission lifetime and no significant change from the prelaunch derived estimates.