Spaceborne SAR Interferometry for Airport Obstruction Charts

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Solution Overview

Problem

Current methods for creating accurate tridimensional geographic information data for aeronautical infrastructure, such as Airport Obstruction Charts, are slow, costly, and often obsolete due to the limitations of airborne LiDAR technology, which requires low flight altitudes, causes airfield operation disruptions, and takes too long to process, while spaceborne SAR offers a more efficient but underutilized alternative for obstacle data acquisition.

Innovation Solution

Implementing spaceborne Synthetic Aperture Radar Interferometry technology to rapidly generate and update Digital Surface Models, integrating with other data types for precise obstacle detection and chart updates, allowing for frequent updates without disrupting airfield operations and meeting ICAO's Annex 15 requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If airborne LiDAR is used for obstacle data acquisition, then measurement precision is improved, but loss of time increases and productivity decreases

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoiddata acquisition and processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/optical LiDAR system with a spaceborne SAR interferometry system. The SAR system uses radar waves instead of laser beams, and the interferometry processing method enables rapid detection of obstacle height changes without requiring complex point-by-point processing, thus reducing time loss while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from airborne to spaceborne platforms, adding the temporal dimension to the observation. By using SAR interferometry with multiple satellite passes over time, the system can detect obstacle height changes and update obstruction charts rapidly, achieving both high precision and fast update rates that were not possible with single-pass airborne LiDAR.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If airborne LiDAR is used for data acquisition, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex airborne LiDAR processing system with a spaceborne SAR interferometry approach. The SAR system uses established radar processing techniques and interferometry algorithms that, while computationally intensive, benefit from the stable platform and systematic data collection approach, reducing overall system complexity compared to coordinating multiple airborne sensors and processing streams.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If airborne LiDAR is used for obstacle detection, then measurement precision is improved, but loss of time increases due to processing requirements

Engineering Contradiction:
Improveobstacle height accuracyVSAvoidchart update rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent adds the temporal dimension through spaceborne SAR interferometry with multiple satellite passes. This enables the system to detect obstacle height changes over time and produce updated obstruction charts at rapid intervals (weekly or monthly), dramatically improving productivity and chart update rate while maintaining the precision needed for aviation safety.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spaceborne SAR system provides continuous or near-continuous monitoring capability as satellites pass over the area of interest. This continuous data collection enables ongoing detection of obstacle changes without interruption, maintaining high productivity and enabling frequent chart updates unlike the periodic airborne LiDAR surveys.

Inventive Principle:
Principle #20Continuity of useful action

4Productivity

If spaceborne SAR interferometry is used for data acquisition, then productivity is improved, but measurement precision may be compromised

Engineering Contradiction:
Improvedata acquisition speedVSAvoidobstacle detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent employs interferometry processing that compares phase information from multiple SAR images to detect changes in obstacle height. This feedback mechanism allows the system to maintain high measurement precision by analyzing the phase differences and temporal changes, ensuring accurate obstacle detection while achieving rapid data acquisition through spaceborne platforms.

Inventive Principle:
Principle #23Feedback

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 reduces data acquisition and update times, enhances accuracy, and allows for continuous monitoring of obstacles, ensuring safer airport operations with improved temporal and spatial resolution, fulfilling ICAO's numerical requirements and reducing operational costs.

Implementation Method 1

spaceborne Synthetic Aperture Radar platforms

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

interferometric data using synthetic aperture radars

Methodology Applied
Scientific EffectInterferometry: Interference

Data Source

PatentEP2330435B1Method to generate airport obstruction charts based on a data fusion between interferometric data using synthetic aperture radars positioned on spaceborne platforms and other types of data acquired by remote sensors
Publication Date: 2015.09.16 ANA AEROPORTOS DE PORTUGAL
  • EP2330435B1 patent drawingFigure 1
  • EP2330435B1 patent drawingFigure 2
  • EP2330435B1 patent drawingFigure 3a~3c

AI summary

The proposed invention describes a method to generate Airport Obstruction Charts, based on a fusion between interferometric data acquired by Synthetic Aperture Radars positioned in spaceborne platforms, and other types of data acquired by remote sensors. It is characterized by the following stages;- Conversion of pre-existent analog data of the surveyed areas to digital format:-Vectorization of the data;- Data analysis already in digital format;- Generation of Digital Surface Model (MDS, being the input data structure to be used by the Land Change Detection Algorithm, in raster format;- Comparison between the initial Digital Surface Model and the new data acquired in a later epoch;- Comparison between the base Digital Surface Model (MDS) and the altimetric data structure derived from interferometric data obtained from the Synthetic Aperture Radars positioned in spaceborne platforms;- Registration and georeferencing of the Digital Surface Model (MDS);- Cut the image to ensure that all the surveyed area is correctly identified;- Resampling of the raster models to be compared with those obtained between the initial and latter epochs, in order to present the same number of pixels either in line or column, representing the same surveyed area;- Detection of land changes in order to compare the elevations in both digital surface models (MDS) obtained from different epochs, to produce a third raster model;- Overlay between the raster images of the objects considered as obstructions and the Airport Obstruction Chart in vector format;- New obstructions validation;- and dissemination of the new Airport Obstruction Charts to the relevant authorities.