Bistatic SAR image formation

Synthetic aperture radar (SAR) allows all-weather, day-and-night surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, in which the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This paper presents part of the work undertaken at QinetiQ examining the techniques and additional complications involved in producing high-resolution bistatic SAR imagery. The work presented here focuses on a fully airborne, synchronised bistatic SAR demonstration using QinetiQ’s enhanced surveillance radar and the Thales/QinetiQ airborne data acquisition system, which took place in September 2002. Some of the bistatic imagery from the trial are presented here and compared and contrasted with the monostatic imagery collected at the same time.