A Matching Method for Establishing Correspondence Between Satellite Radar Altimeter Data and Transponder Data Generated During Calibration

This letter presents a method for matching satellite radar altimeter data and transponder data generated during in situ calibration. The transponder generates a measurement error when it measures the arrival time of the altimeter´s transmitted signal and embeds the error in both the transponder´s recorded data and the altimeter´s recorded data. The second-order finite difference sequence of this error sequence can be extracted from the raw data; thus, the correspondence between two identical but mismatched second-order difference sequences can be uniquely established. The measurement error is utilized, and a data matching method that can uniquely establish the correspondence between the altimeter´s recorded data sequence and the transponder´s recorded data sequence is presented. This postprocessing method does not increase the real-time signal processing workload of the transponder. Furthermore, the principles underlying this method can be used for any transponder that can adjust the response signal delay during calibration.