Airborne Gravity Gradient Data Terrain Correction
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Solution Overview
Problem
Existing methods for processing airborne gravity gradient data struggle to accurately distinguish between small gravity gradient anomalies caused by valuable materials and larger variations due to topographical changes in the terrain, especially when the materials are located below the surface.
Innovation Solution
A method that involves calculating a theoretical gravity gradient response of the terrain using provided terrain and flight path data, and then correcting the gravity gradient data by subtracting this response from the measured data to isolate anomalies from deeper sources, using techniques such as curve fitting and adaptive sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If gravity gradient data is collected over terrain with topographical changes, then coverage area is increased, but measurement precision deteriorates due to larger terrain-induced variations masking small anomalies
Solution Approach 1:
The patent extracts and removes the terrain effect component from the total gravity gradient signal by calculating theoretical terrain response and subtracting it from measured data, isolating the anomaly signal from deeper sources
Solution Approach 2:
The patent performs preliminary calculation of theoretical terrain gravity gradient response before anomaly detection, using terrain data and flight path information to pre-compute what the terrain contribution should be, enabling subsequent subtraction to isolate anomalies
2Loss of time
If terrain correction is performed using existing methods, then processing time is reduced, but measurement precision deteriorates due to insufficient accuracy in distinguishing terrain effects from anomalies
Solution Approach 1:
The patent calculates theoretical terrain response in advance using provided terrain data and flight path information, enabling efficient subtraction from measured data without requiring complex real-time processing during the actual anomaly detection phase
Solution Approach 2:
The patent creates a theoretical model copy of the terrain gravity gradient response based on terrain data, which can then be directly subtracted from measured data to isolate anomalies, avoiding the need for complex inverse problems
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 enhances the detection of small anomalies from deeper sources by effectively removing terrain effects, improving the precision of locating valuable materials like ores or oil deposits.
Implementation Method 1
Valuable materials in the ground, such as ores or oil deposits, can be detected directly or indirectly using suitable airborne gravity gradiometers... Such valuable materials usually have a density other than that of surrounding materials, which results in a local variation or 'anomaly' in gravity gradient
Implementation Method 2
The measured gravity gradient data is integrated in the time domain and then corrected for terrain effects
Data Source
AI summary
The present disclosure provides a method of processing gravity gradient data indicative of an output generated by an airborne gravity gradiometer that is moving along a flight path over a terrain. The method comprises the step of providing the gravity gradient data. The gravity gradient data comprising gravity gradient data elements that are associated with respective flight path segments of the airborne gravity gradiometer. Further, the method comprises providing terrain data indicative of a topography and a density or a density distribution of the terrain above a datum that is below the surface of the terrain over which the airborne gravity gradiometer is moved. The method also comprises providing information concerning the flight path of the airborne gravity gradiometer in three dimensions. In addition, the method comprises calculating the gravity gradient response of the terrain using the provided terrain data and the provided information concerning the flight path. The gravity gradient terrain response data is calculated for a plurality of locations of the gravity gradiometer along at least some of the flight path segment. In addition, the method comprises correcting the gravity gradient data by forming a difference between the calculated gravity gradient terrain response of the terrain topography and the gravity gradient data.