Abstract: In order to meet the current demand for high-precision calibration of satellite-borne remote sensors, a high-altitude spectral radiance meter has been developed, which can be applied to the radiance method instead of the traditional site calibration method to improve calibration accuracy. The instrument has a spectral range from 400 nm to 2500 nm, and can be mounted on a high-altitude balloon platform to measure the reflected radiance to the ground directly at an altitude from 18 km to 35 km. The opticalmechanical system of the instrument is mainly composed of a front integrated lens barrel, a dispersion module and the optical-mechanical temperature control module. In order to verify the reliability of the high-altitude spectral radiance meter and the accuracy of the measured data, a comparison experiment between this instrument and the SVC spectrometer of Spectra Vista (USA), as well as a high-altitude flight experiment, was carried out in Dachaidan, Qinghai. The experimental results show that there is good consistency in the radiance measured by the two instruments, with a deviation of the two instruments generally within ±1% and a maximum deviation within ±3.5%. In the high-altitude flight experiment, the instrument can keep stable at an altitude of 25 km in the six-hour flighting, and the temperature of each module and detector remains at the setpoint. In the end, the result of high-altitude measurement radiance was obtained. The experimental result has verified the reliability of the entire instrument, indicating that the developed instrument can meet the high-precision calibration requirements of satellite remote sensors and is suitable for the high-altitude high-precision measurement.

Key words: remote sensing, opto-mechanical design, radiance basis method, welkin