Safe Landing Point Search Using Contour Lines and Largest Empty Circles
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Solution Overview
Problem
Existing methods for landing unmanned aerial vehicles (UAVs) face challenges such as high maintenance costs, susceptibility to disturbances, and complexity in real-time position and altitude corrections, especially when guiding UAVs to moving landing points.
Innovation Solution
A safe landing point search device that uses contour line information from a terrain map to identify a safe landing point by generating contour lines based on a triangulated irregular network and searching for largest empty circles (LECs) within these contour lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If image-based automatic landing method using camera is used, then additional manpower and facilities are reduced, but processing complexity increases and processing time is delayed due to real-time position and altitude corrections using additional sensors
Solution Approach 1:
The patent extracts and removes the need for additional sensors (GPS, inertial sensors, laser sensors) that were previously required for real-time position and altitude corrections. By using contour line information from terrain maps to directly determine landing points, the system eliminates the complex integration of multiple sensor data streams, thereby reducing device complexity while maintaining efficient processing time.
Solution Approach 2:
The patent uses contour line information from terrain maps as a simplified representation (copy) of the actual terrain structure. Instead of processing raw 3D spatial data from multiple sensors, the system works with 2D contour line representations that capture essential elevation information, reducing computational complexity while preserving the necessary geometric relationships for safe landing point identification.
2Adaptability or versatility
If real-time image processing is performed during tracking of landing target, then moving landing point guidance is enabled, but recognition algorithm and operation occupy large part of image processing time, delaying immediate reaction of flight vehicle
Solution Approach 1:
The patent performs preliminary actions by pre-generating contour line information from terrain maps before the landing process. The contour lines representing different elevation levels are prepared in advance, allowing the system to quickly query safe landing areas without performing complex real-time 3D reconstruction or terrain analysis during the critical landing phase, thus enabling fast response while maintaining adaptability to moving targets.
Solution Approach 2:
The patent transitions from processing 3D spatial data to working with 2D contour line representations. By converting the three-dimensional terrain information into two-dimensional contour maps with elevation labels, the system reduces computational dimensionality and complexity, enabling faster processing speeds while maintaining the ability to adapt to moving landing points through efficient 2D image processing techniques.
3Measurement precision
If contour lines are generated using terrain map and largest empty circle searching is performed, then safe landing point identification accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent employs the largest empty circle (LEC) searching algorithm as a computationally efficient method to identify safe landing points. Instead of using complex optimization algorithms or exhaustive search methods, the LEC approach provides a simple geometric solution that quickly identifies areas with sufficient clearance from obstacles, achieving high identification accuracy with minimal computational resources and complexity.
Data Source
AI summary
A safe landing point search device for searching for a safe landing point of an unmanned exploration device that lands on and explores a celestial body, includes a terrain map obtaining unit configured to obtain a terrain map, a contour line generating unit configured to generate contour lines based on a reference minimum height value and a height interval value by using the terrain map, a largest empty circle (LEC) searching unit configured to search for one or more LECs having a radius greater than or equal to a lower-limit radius in a contour line map including the contour lines, and a safe landing point outputting unit configured to output a safe landing point having a largest radius among the one or more LECs and transmit the safe landing point to the unmanned exploration device.