Insar Absolute Phase Fuzzy Estimation Method Based on Coarse Digital Elevation Map

Abstract

The present invention discloses a coarse digital elevation map-based InSAR (interferometric synthetic aperture radar) absolute phase fuzzy estimation method. The main objective of the invention is to solve the problem of requiring ground accurate control points and the problem of complicated calibration computation in real-time digital elevation map generation of an existing radar. The method includes the following steps that: 1) the reference average height of a target scene is determined according to the coarse digital elevation map of the target scene; 2) a scene center slope distance is estimated according to the reference average height of the target scene; 3) the unwrapping phase and absolute phase of the scene center reference point are calculated; 4) the absolute phase fuzzy number of the whole scene is calculated according to the unwrapping phase and absolute phase of the scene center reference point; and 5) a real-time digital elevation map is obtained through inversion according to the absolute phase fuzzy number of the scene. With the coarse digital elevation map-based InSAR absolute phase fuzzy estimation method of the invention adopted, the absolute phase fuzzy number of a ground scene according to which no ground accurate control points exist and height changes sharply, can be estimated correctly and quickly. The method can be applied to the real-time signal processing system of an airborne radar.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and in particular relates to an absolute phase ambiguity estimation method of an interferometric synthetic aperture radar InSAR, which can be used in a radar real-time signal processing system for the purpose of obtaining a digital elevation map of a ground scene with elevation fluctuations. Background technique [0002] The application of interferometric synthetic aperture radar InSAR is extremely extensive, and the most direct application is to obtain digital elevation maps. The digital elevation map of the ground scene obtained by single flight through InSAR relies on the wave path difference of the radar beams of the two antennas, which is reflected in the phase of the radar echoes of the two antennas. Solving the absolute phase of the whole scene from the radar echo is the prerequisite for obtaining the digital elevation map of the whole scene. When there is no precise control poi...

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Problems solved by technology

Moreover, when the above method performs real-time estimation, the inversion of the angle of view under the antenna is required, and the arc cosine calculation is required, and the result of the arc cosine should be between [-π / 2, π / 2]. Therefore, the disadvantage of the above method is that : The correct result of the inverse cosine calculation needs to be judged and obtained, otherwise there will be problems in the inversion, and this method is not suitable for radar platforms with drastic changes in motion state, and the situation where the height of the scene fluctuates greatly

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