Azimuth ambiguity suppression method for along track interferometry SAR ocean current inversion

Abstract

The invention relates to an azimuth ambiguity suppression method for along track interferometry SAR ocean current inversion, and belongs to the technical field of ocean remote sensing. The method comprises the following steps of: converting an along track InSAR two-channel SAR complex image corresponding to a certain region of a sea surface which has ocean currents to be measured to range frequency-Doppler frequency domain after registration; calculating a covariance matrix of an along track InSAR by using independent identical distribution samples of a range frequency dimension; calculating acurve of along track interferometry characteristic spectrum entropy which changes with Doppler frequency according to the calculated covariance matrix; according to the curve, finding maximum pointsin a left half part and a right half part of the curve separately; then removing all Doppler units at the left side of the left side maximum points of the curve and removing all Doppler units at theright side of the right side maximum points of the curve; determining a threshold value of the characteristic spectrum entropy by using an adaptive iterative method; removing Doppler units with the characteristic spectrum entropy greater than the threshold value; and calculating range velocity of the ocean currents by using an interference method based on obtained InSAR data.

Description

technical field [0001] The invention belongs to the technical field of marine remote sensing, and relates to an azimuth fuzzy suppression method suitable for along-track interferometric SAR aiming at ocean current inversion in coastal sea areas. Background technique [0002] Ocean currents are one of the most basic and important elements in many processes in the ocean and meteorology fields, and they have a restrictive effect on various biological, chemical and physical processes in the ocean. Ocean currents govern the movement of ocean water around the globe, transporting and mixing nutrients, salts, gases, organisms and heat throughout the ocean. This means that understanding the existence, direction and speed of ocean currents is important for business, social services and scientific research. For example, industries such as oil and gas exploration require reliable current data to ensure safe working conditions; ships rely on current information for route planning, to mi...

AI Technical Summary

Problems solved by technology

However, this method has an obvious disadvantage: because some pixels are discarded in the SAR image domain, the flow field information in some areas will be lost

Therefore, this method is not suitable for sea surface scenarios and cannot be applied to flow field inversion

To sum up, so far, there is no effective along-track InSAR azimuth ambiguity suppression algorithm for ocean current inversion in the "near-shore" sea area.

Images