Validation of the TET-1 satellite imaging sensor

Abstract

The release of greenhouse gases and aerosols from �res has a large in uence on global climate: on average, �res are responsible for up to 30% of anthropogenic CO2 emissions. Currently, however, there are no suitable instruments for more precisely estimating the quantity of emissions and thus their impact on the climate. The German Aerospace Center (DLR) is contributing to the FireBIRD constellation, which will consists of the two satellite TET-1 (Technology Test Platform) launched 2012, and BIROS (Bispectral Infrared Optical System) to be launched in 2016. FireBIRD is mainly dedicated to scienti�c investigation of the issues involved as well as to early �re detection from space. The satellite and detector approach is based on proven DLR technology achieved dur- ing the BIRD (Bispectral Infrad Detection) mission, which was launched in 2001 and was primarily used for observation of �res and volcanic ac- tivity until 2004. The Payload of TET and BIROS (equal sensor system) has spectral channels in visible (VIS), near infrared (NIR), mid-wave (MIR) and a thermal infrared (TIR) channel. In the spatial domain the instrument has 5184 pixels for the VIS/NIR and 1000 pixels for the MIR/TIR channel with a Ground Sampling Distance (GSD) of about 40m (VIS/NIR) and 160m (MIR/TIR). The paper describes the satellite as well as sensor system itself and gives some results of sensor data takes form the TET Satellite. For the scienti�c use of the TET-1 and later of BIROS data it is essential to know the reached performance of the optical instruments operating in-orbit. The main part of the paper explains the validation results of the sen- sor system. The procedures and parameters includes measurements of the dark signal (DS), noise behavior and signal to noise (SNR). The ge- ometrical imaging performance will be described using the modulation transfer function (MTF). With the calculated attitude parameters a direct georeferencing is pos- sible. Deviations of spatial features from expected absolute geolocation gives an information of the accuracy of the attitude measurement system.