3D Information Processing for UAV Flight in GPS-Denied Spaces
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Solution Overview
Problem
It is challenging to control the flight of unmanned aerial vehicles (UAVs) in areas where navigation signals from navigation satellites are difficult to receive, such as under bridges or in tunnels, due to signal obstruction.
Innovation Solution
A flight control technique using a combination of a total station and a laser scanner that obtains point cloud data to determine the allowable movement range of the UAV, allowing it to maintain a constant distance from structures without relying on navigation signals. This involves pre-flight laser scanning to gather first point cloud data and real-time scanning during flight to gather second point cloud data, which is used to detect objects above and below the UAV, calculating the vertical movement range based on this data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flight control uses navigation signals from navigation satellites, then positioning accuracy is improved, but reliability deteriorates in areas with signal obstruction such as under bridges or in tunnels
Solution Approach 1:
The patent introduces laser scanners and total stations as intermediary devices to establish a ground-based positioning system. These devices act as mediators between the UAV and the control system, enabling positioning through laser ranging and coordinate calculation without relying on satellite navigation signals. The ground stations transmit laser beams to track the UAV and calculate its position using coordinate geometry, thus resolving the contradiction by providing an alternative positioning mechanism that works in signal-obstructed areas.
Solution Approach 2:
The patent replaces the electromagnetic-based satellite navigation system with a mechanical/optical-based ground-based laser tracking system. Instead of relying on radio frequency signals from satellites, the system uses laser beams for ranging and total station measurements for position calculation. This substitution enables reliable flight control in environments where satellite signals are blocked, as the ground-based optical system can operate independently of atmospheric conditions and signal obstruction.
2Difficulty of detecting and measuring
If laser scanning is performed in real-time during flight, then obstacle detection capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the obstacle detection function between two distinct components: ground-based laser scanners that perform real-time scanning during flight, and pre-flight laser scanners that create baseline point cloud data. This segmentation allows the system to use different scanning strategies for different purposes - real-time scanning for dynamic obstacle detection and pre-flight scanning for environmental mapping. The separation of functions reduces the complexity burden on any single device while maintaining comprehensive obstacle detection capability.
Solution Approach 2:
The patent performs preliminary laser scanning before flight to create point cloud data of the flight environment. This pre-acquired data serves as a baseline for comparing real-time scanning results, enabling the system to detect changes and obstacles more efficiently. By having the environmental map prepared in advance, the real-time system only needs to detect deviations from the baseline, reducing processing complexity during flight while maintaining high obstacle detection 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
Enables UAVs to fly safely and maintain a constant distance from ceilings or ground surfaces in areas with obstructed navigation signals, ensuring accurate positioning and obstacle avoidance.
Implementation Method 1
a laser scanner configured to perform laser scanning along a vertical plane
Implementation Method 2
the total station configured to track a target by using laser light
Data Source
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AI summary
A mobile body is controlled even in a place in which a navigation signal is difficult to receive from a navigation satellite. A three-dimensional information processing unit operates a device or a functional part which measures three-dimensional coordinates of a controlled target and operates a laser scanner or a laser scanning part which obtains three-dimensional point cloud data of the target. The unit includes a positioning section that operates the device or the functional part which measures the three-dimensional coordinates, to calculate the three-dimensional coordinates, and includes a scan controlling section that obtains the three-dimensional point cloud data from the laser scanner or the laser scanning part. The unit also includes a range calculator that calculates a movable range of the target from the three-dimensional coordinates and the three-dimensional point cloud data, and includes a controlled target position calculator that calculates a position of the target in the movable range.