Registration of multi-frequency SAR imagery using phase correlation methods

The advancing development of low-cost small spacecraft platforms enables Earth observation constellation missions using a variety of imaging methods, including multistatic (single-transmitter, multiple-receiver) interferometric synthetic aperture radar (InSAR). Image registration is a necessary step preceding interferometric analysis of multistatic or repeat-pass SAR imagery. An effective image registration method for a potential InSAR constellation mission must not incur errors from distortions caused by imaging geometry and temporal changes in the terrain, and should as well be applicable to multi-frequency SAR registration and potentially multi-modal registration with optical imagery. Furthermore, the ability to register and process images onboard the spacecraft is desirable due to power and downlink limitations on a small platform. Herein we demonstrate a frequency-domain registration method on single-frequency, repeat-pass, and dual-frequency SAR imagery, for use in a future small satellite remote sensing constellation.