Potential and shortcoming of small satellite for topographic mapping

Kurzfassung

High resolution mapping systems follow the trend to smaller ground sample distances (GSD) making use of the best technology available at the given time. From the 80 m GSD of ERTS in 1972, the GSD now approached 1 m and even less for civil applications. Mass and power consumption of spacecrafts and imaging instruments follow similar trends in conjunction with the immense improvements in very divers fields of technology. SAR systems are an alternative to passive optical systems; they also benefit from the technology improvements. But the most promising prospects for high resolution mapping with small satellites are connected with passive optical systems. The paper tries to give a MTF based metrics and analytical method to assess how far we can go with decreasing instrument size and decreasing the GSD at the same time and what features the spacecraft needs to provide. In this context the paper deals with such important parameters for topographic mapping with small satellites like spatial resolution, radiometry, pointing accuracy and stability. The parameters are derived from a MTF based metrics. It is shown that the imagers as well as the spacecraft bus need to follow certain rules to allow high resolution imaging aboard of small satellites.