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

Bo Liu,Lifu Chen,Xiaohong Sui,Weiya Kong,Zhengfang Lu

doi:10.1109/access.2021.3058767

Abstract

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.

Highlights

Satellite radar altimeters can be used for sea-level measurement and to obtain the global ocean geoid [1]
Satellite radar altimetry has been utilized for over three decades; the first space-borne radar altimeter on the geodetic satellite (GEOSAT) was used to acquire high-precision ocean surface topography (OST). Altimetry missions, such as TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3, have provided a large amount of sea elevation data, which provides a basis for scientific research
Simulation results of the relative elevation accuracy of each elevation measurement parameter error are shown in Fig. 3a–f

Summary

INTRODUCTION

Satellite radar altimeters can be used for sea-level measurement and to obtain the global ocean geoid [1]. Satellite radar altimetry has been utilized for over three decades; the first space-borne radar altimeter on the geodetic satellite (GEOSAT) was used to acquire high-precision OST Altimetry missions, such as TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3, have provided a large amount of sea elevation data, which provides a basis for scientific research. Ge et al [13] analyzed the error sources in InSAR measurements, showing that the different degrees of decorrelation factors have different effects on the relative ocean elevation measurement accuracy in radar bands. Liu et al [1] deduced the relationship between relative ocean height measurement accuracy and system parameters; their theoretical results show that interferometric phase error is the primary factor affecting the accuracy of relative ocean elevation measurements.

INSAR ELEVATION MEASUREMENT PRINCIPLE

CONCLUSION