In this research, we aim to improve the accuracy of satellite-derived data by developing a new indirect calibration technique. The technique uses an optical sensor with improved traceability down to SI units. The spectrometer, along with supporting equipment, will be mounted aboard a remotely operated helicopter as an efficient and inexpensive remote sensing tool. The onboard instruments are controlled using a minicomputer connected to a ground computer via a remote network connection, so that real-time measurements can be observed and controlled on the ground by the operator. The spectrometer, which is to be a palm-sized detector, operates in the VIS-NIR spectral range. The technique has the potential to provide accurate, low-cost reference surface measurements for large and difficult terrains over a short period of time, which can then be used to calibrate and validate satellite-derived measurements. The optical sensor, selected to be a spectrometer photodiode array, will be calibrated against a fixed-point black body. This black body provides a high-emissivity, high-stability reference source of known spectral radiation over the emitted spectral range. However, the highest fixed point defined by the current International Temperature Scale (ITS-90) is the copper point at 1357.77 K [10], which is not high enough to provide sufficient optical power. at short wavelengths. this work aims to calibrate the spectrometer against a eutectic fixed point, which uses a metal-carbon alloy rather than pure metals [11]. These fixed points have the potential to provide a spectrally radiant black body source with melting points up to 3500 K [12]. However, thermodyn...... middle of paper ... sources, rather than lasers, will be studied. This approach provides a cheap, hence available, system that can be used to correct stray light in these photodiode arrays on a commercial scale.5- The radiometric performance of the photodiode array spectrometer needs to be evaluated. Correction for any inconsistency between laboratory and field measurements should be provided.6- Identify the blackbody temperature at the photodiode array spectrometer that can be calibrated and develop a system to calibrate the spectrometer relative to it .7- Develop the helicopter-based system and identify supporting equipment that can be used with a long photodiode array instrument. These should include an imaging camera and a global positioning system, so that the spectral and imaging characteristics of the site can be presented along with its spatial information..