Accuracy Analysis of the InSAR Altimeter in Relative Elevation Measurements of the Sea Surface

This study introduces an interferometric synthetic aperture radar (InSAR) altimeter for sea-level elevation measurement. To evaluate the system capability and demonstrate that the InSAR altimeter can meet the application requirements of sea-surface elevation measurement, the main factors affecting relative elevation accuracy are analyzed. The mathematical expressions for each elevation measurement parameter and sea-surface elevation are derived along with the error transfer coefficients between each elevation measurement parameter and relative sea-surface elevation accuracy. Using the single-control variable method, the sensitivity of each elevation measurement parameter to relative elevation accuracy is obtained. By introducing the parameter values into the derivation formula of theoretical analysis, theoretical results are obtained. The theoretical results are compared with the simulation results, which helps to verify the validity of the error analysis. Results reveal that the interference phase error is the main factor affecting the accuracy of relative ocean height measurements. This work could significantly guide the subsequent design of the InSAR altimeter system.