Single-Satellite SAR Reconstruction for Bridge Displacement
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Solution Overview
Problem
Existing bridge displacement analysis using satellite-based synthetic aperture radar (SAR) can only determine Line Of Sight (LOS) displacement, making it difficult to accurately determine the direction and magnitude of actual bridge displacement without data from multiple satellites.
Innovation Solution
An information processing apparatus and method that calculates bridge displacement using irradiation-direction displacement data from a single satellite, employing constraint conditions and parameter updates to derive accurate displacement amounts in specific directions through iterative processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If displacement analysis uses two artificial satellites in different orbits (2.5D analysis), then the direction and magnitude of actual bridge displacement can be determined, but the applicability is limited to very few cases where the same target is irradiated by two different satellites
Solution Approach 1:
The patent transforms the problem from a 2D projection measurement (LOS displacement) to a 3D displacement reconstruction by introducing temporal dimension (multiple observation times) and utilizing the geometric relationship between satellite orbit, target object, and displacement direction to calculate three-component displacement vectors from single-satellite observations
2Adaptability or versatility
If displacement analysis uses only one satellite, then the applicability is improved, but the ability to determine the direction and magnitude of actual bridge displacement is insufficient
Solution Approach 1:
The patent employs iterative optimization where initial displacement estimates are refined through feedback loops that minimize the difference between observed LOS displacement and calculated LOS displacement from the three-component displacement vector, progressively improving measurement precision
Solution Approach 2:
The patent changes the parameter representation from direct LOS displacement to three-component displacement vectors (east-west, up-down, north-south directions) that can be derived from single-satellite observations through geometric relationships and iterative optimization
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
Enables precise calculation of bridge displacement in both bridge axis and vertical directions using data from a single satellite, improving accuracy and applicability of displacement analysis.
Implementation Method 1
bridge displacement analysis that uses satellite-based synthetic aperture radar (SAR) has been proposed. In bridge displacement analysis using satellite SAR, radio waves are emitted from a satellite toward a bridge at set intervals and the reflected waves are received
Implementation Method 2
The phase difference between the reflected waves is then calculated by interference processing
Data Source
AI summary
An information processing apparatus includes; a data acquisition unit that acquires irradiation-direction displacement data that was generated by irradiating a target object with radio waves from a flying object and indicates an amount of displacement of the target object in an irradiation direction of the radio waves; a constraint condition calculation unit that, using a constraint condition defining a relationship between a specific parameter and an amount of displacement of the target object, calculates a set-direction displacement amount candidate that satisfies the constraint condition; a displacement calculation unit that calculates an irradiation-direction displacement data candidate by applying the set-direction displacement amount candidate to an expression showing a relationship between the irradiation-direction displacement data and the amount of displacement in the set direction; and a parameter update unit that updates the specific parameter using a difference between the irradiation-direction displacement data candidate and the irradiation-direction displacement data.