Multi-Temporal MAI Interferogram Stacking for Along-Track Displacement
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Solution Overview
Problem
Current multi-temporal multiple aperture SAR interferometry (MAI) technologies face limitations in measuring small-scale ground surface displacement in the along-track direction with sufficient precision, typically only able to detect displacements of tens of centimeters or more, while struggling to observe continuous displacements occurring at a few centimeters per year.
Innovation Solution
A method and apparatus for stacking multi-temporal MAI interferograms, involving interferogram generation, residual interferogram creation by removing low-frequency phase components, and stacked interferogram formation using complex conjugate multiplication, with error correction via polynomial models, to enhance precision and coherence, thereby improving the measurement of ground surface displacement in the along-track direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MAI measurement schemes are used, then large-scale ground surface displacement (tens of centimeters to meters) can be observed, but small-scale continuous displacement (few centimeters per year) cannot be detected with sufficient precision
Solution Approach 1:
The patent segments the measurement process into multiple temporal interferogram observations and stacks them together. By dividing the observation into multiple interferometric pairs acquired at different times and combining them through stacking, the precision is improved from centimeter-level to millimeter-level, enabling detection of small-scale continuous displacement that cannot be observed with single-pair MAI schemes.
2Measurement precision
If multi-temporal MAI interferogram stacking is performed, then precision of along-track displacement measurement is improved to centimeter or higher level, but measurement of large-scale displacement becomes less effective
Solution Approach 1:
The patent applies preliminary error correction to each individual interferogram before stacking. By correcting phase errors, atmospheric artifacts, and geometric distortions in advance for each interferometric pair, the stacking process becomes more effective and the final measurement achieves higher precision without requiring overly complex post-processing.
3Measurement precision
If conventional InSAR is used, then displacement in LOS direction can be measured, but displacement in along-track direction cannot be measured with sufficient precision
Solution Approach 1:
The patent transitions from measuring only LOS direction displacement (conventional InSAR) to measuring along-track direction displacement by utilizing the temporal dimension through multi-temporal interferogram stacking. This dimensional approach enables precise measurement of ground surface displacement in the along-track direction, complementing the conventional LOS measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly enhances the precision of ground surface displacement measurement in the along-track direction to a level of 1 cm/yr, enabling accurate observation of minute displacements, such as those in geotectonic movement areas, and facilitating the extraction of three-dimensional ground surface displacement data.
Implementation Method 1
generating a stacked MAI interferogram based on a phase difference between the stacked forward-looking interferogram and the stacked backward-looking interferogram
Implementation Method 2
generating residual forward-looking interferogram and residual backward-looking interferogram by removing low-frequency phase components from InSAR interferograms
Data Source
AI summary
An apparatus and method for stacking multi-temporal MAI interferograms Disclosed are disclosed herein. The apparatus includes a processor configured to: generate a forward-looking InSAR (Interferometric Synthetic Aperture Radar) interferogram and a backward-looking InSAR interferogram of multi-temporal interferometric pairs; generate a residual forward-looking interferogram and a residual backward-looking interferogram by removing low-frequency phase components from the forward-looking InSAR interferogram and the backward-looking InSAR interferogram; generate a stacked forward-looking interferogram and a stacked backward-looking interferogram by separately stacking the residual forward-looking interferogram and the residual backward-looking interferogram; and generate a stacked MAI interferogram based on a phase difference between the stacked forward-looking interferogram and the stacked backward-looking interferogram.