A Simple Offset “Calibration” Method for the Accurate Geographic Registration of Ship-Borne X-Band Radar Intensity Imagery

Abstract

X-band radar remote sensing of the ocean surface using ground-based installations and radar intensity imagery is a mature technology for the determination of ocean wave properties. In order to transition the analytical methods to data collected from a moving vessel the accurate geo-registration of radar images must be performed. However, finite offsets in azimuth, range and time are generated by the physical installation of equipment aboard a vessel that may not be measurable. This paper details a simple, yet robust method to “calibrate”data recorded by an arbitrary equipment installation to allow accurate geo-registration of the radar imagery. Time-integrated radar images are generated using a set of time-stamped radar intensity images and high-frequency, high-accuracy vessel heading and position information (from global satellite navigation systems and inertial navigation systems). The time-integrated image sharpness is found to be maximal for correctly determined angular, range, and time offsets. The requirements to form an operational system from the proposed method are also discussed.

Keywords

• Radar remote sensing
• radar imaging
• calibration
• sea surface