Theoretical Considerations of Bi- and Multistatic SAR

摘要

The report discusses a new system concept for ground surveillance based on bi- and multi-static synthetic-aperture radar (SAR). The system has a number of tactical advantages compared to mono-static SAR, e.g. reduced vulnerability and improved update rate. The missile threat is reduced since the transmitting platform is operated at larger stand-off distance and jamming threat is reduced since the receiving platforms are passive and do not emit radar signals. The update rate increases since receiver stand-off distance is reduced and the synthetic aperture can be completed in a shorter time. The disadvantages of bi-static SAR are technical difficulties associated with synchronizing the transmitter and receiver, and to focus the SAR image without information of the transmit antenna position. The report describes bi-static SAR image formation and a model for image resolution. The model is verified by simulations and formulas for image resolution are derived. It is shown that bi-static SAR requires approximately twice the aperture angle to achieve the same resolution as mono-static SAR.