Miniaturized Multispectral VNIR/SWIR Imager for Small Satellites - System Design

In this article we will present miniaturized optical payloads for 3U CubeSat satellite format. Optical payload consist of imaging unit based on a sensor with a wide spectral response (from Visual to Short Wave Infra-Red). Many small band pass filters (up to 20) can be put in front of the sensor to achieve multispectral imaging with squared sensor. This way the rectangular sensor acts like a line scan sensor with group of lines detecting same spectrum. Optical payload performance is limited by satellites physical constraints and weight. Optics consists of multiple lens design with high aperture size and high wavelength transmission. Miniaturization has big influence on performance of optical instrument, leading to limitations on spatial resolution. We pay special attention to provide decent effective ground sampling distance appropriate for sensing of vegetative and environmental processes on Earth. Special attention was devoted to the options for appropriate Sun-Synchronous orbits (SSO) regarding revisit frequency and global coverage limited by imager performance and satellite lifespan limitation. With predicted satellite SSO orbit at height of 487 km (19D290R) global coverage can be made in 19 days and revisit frequency of3.2 days for observed latitudes above 46° (northern Europe).