Ground-Based Passive Radar Imaging Using Geostationary Satellites—Perspectives and Constraints

Besides traditional remote sensing based on synthetic aperture radar (SAR) satellites that deliver high-resolution and well-georeferenced images from Earth’s surface, there is a big and steadily increasing need for continuous observation of small local areas that cannot be satisfied by the current satellite programs. In contrast to the aforementioned monostatic satellite missions, bistatic configurations employing satellites of opportunity as illuminators and locally separated stationary (passive) receivers observing the local scene of interest feature some attractive benefits like moderate costs and short repeat intervals. In this letter, we highlight the challenges of imaging radar using geostationary satellites as transmitting sources. As an example, data from an experiment of this bistatic configuration obtained with a low-cost receiver system is analyzed and presented. For comparison, the parameters and results of an experiment using the high-resolution SAR satellite PAZ as a transmitter are also shown.