Abstract
The ocean surface current vector contains velocity and direction information, and its acquisition method has important research value in marine applications. Multi-aperture along-track interferometric (MA-ATI) SAR is a novel method of current vector detection. However, due to the lack of real experimental data validation, complex marine environment and diverse system parameters have an uncertain impact on the current measurement ability of MA-ATI SAR. Therefore it is necessary to analyze the measurement accuracy and error of this method in theory. Based on the current measurement principle of MA-ATI SAR, this article deduces and establishes the accuracy and error simulation model, and analyzes the influence of radar parameters and marine environment on the velocity and direction results. In the simulation results, the airborne MIMO-SAR radar parameters is more suitable to use MA-ATI method for accurate current measurement, and the accuracy of current measurement is higher for the current with high velocity and direction close to azimuth. It is found that the variation of wind direction will lead to obvious errors in MA-ATI current results, and it is pointed out that accurate current results can be obtained by iteratively correcting the velocity error of sub-apertures using M4S model.
Highlights
I N 1987, Goldstein and Zebker proposed the Along-Track Interferometric SAR (ATI-SAR) technology [1], which provided the possibility of retrieving large-scale and highresolution ocean surface current fields
The change in wind speed mainly causes the change of ocean surface roughness, which changes the signal-tonoise ratio of the ocean surface echo signal and the change of coherence coefficient, which in turn affects the accuracy of the current measurement, but the literature [20] has shown that the dependence of ATI signal on wind speed is not obvious under moderate wind speed conditions, so this paper does not discuss in detail the influence of wind speed on the experimental results
Multi-Aperture Along-Track Interferometric (MA-ATI) is a new method for detecting two-dimensional current field using existing ATI data, but the application effect in actual data is not clear
Summary
I N 1987, Goldstein and Zebker proposed the Along-Track Interferometric SAR (ATI-SAR) technology [1], which provided the possibility of retrieving large-scale and highresolution ocean surface current fields. The interferometric phase is proportional to the ocean surface velocity in the radar line-of-sight direction, so the traditional ATI-SAR can only measure the range velocity component of the current, and it is difficult to retrieve current vectors. The effects of different radar parameters and current parameters on the accuracy of velocity and direction are simulated and analyzed It analyzes the current vector measurement errors caused by the wind field, and gives an error correction method. Yoshida et al [8] verified the effectiveness of MA-ATI in estimating ocean surface directions through time domain signal simulation, but only analyzed the results of a group of airborne parameters under different sub-aperture squint angles, and pointed out that it is necessary to carry out simulation under more parameters before actual data processing. This paper analyzes the accuracy and error of MA-ATI current measurements, and simulates the results under different system and environmental parameters
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