A novel method for achieving SAR imaging by means of a microsatellite constellation

The current emphasis in the satellite industry is on replacing large satellite platforms with one or more smaller satellites, built at lower cost, yet able to accomplish similar mission objectives. However, it is recognized that such small satellites pose severe constraints on payload volume, mass and power. Thus, the power constraint of synthetic–aperture–radar (SAR) imaging is such that a microsatellite would seem inappropriate. The primary reason for the high–transmit–power requirement is that traditional SAR systems collect the backscatter. Thus, if the forward–scattered element is collected, then the resultant reduction in transmit–power could make it feasible for installation on a microsatellite. Based upon this principle, a novel method by which two microsatellites ‘fly’ in a specific formation to accomplish an SAR imaging mission, bistatically, is proposed. The satellites view a swath of 30 km (chosen to limit the amount of data), at a ground resolution of 30 m, from an altitude of 700 km. The transmitting satellite will be the ‘master’, with the receiver satellite ‘slaved’ off it for synchronization. Applications to a polar–ice–monitoring mission are discussed.