Drone Position Control Under Bridges Without GPS Markers
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Solution Overview
Problem
In areas where GPS signals are difficult to receive, such as under bridges, it is challenging to accurately identify the position of a flying object like a drone, making it hard to determine which part of a structural object it is capturing.
Innovation Solution
A flying object control apparatus that sets multiple coordinate axes, uses different methods to identify the position of the drone along these axes, and controls its flight based on these positions, even in areas with poor GPS signal reception, by employing a setting unit, position identification unit, and flight control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS-based positioning is used in areas under bridges, then positioning can be performed using satellite signals, but positioning accuracy deteriorates due to poor signal reception environment
Solution Approach 1:
The patent introduces an intermediary positioning system consisting of ground-based transmitters and receivers that mediate the positioning function when GPS signals are unavailable. The ground transmitter transmits reference signals that the drone's receiver uses to calculate position relative to known ground points, effectively replacing the satellite-based intermediary with a ground-based intermediary in GPS-denied environments.
Solution Approach 2:
The system changes the fundamental parameter of signal source from satellite-based radio frequencies to ground-based optical or radio signals. By changing the positioning method from satellite triangulation to ground-reference signal processing, the system adapts to environments where the original parameter (satellite signal reception) is compromised.
2Measurement precision
If markers and transmitters are added to areas under bridges, then positioning accuracy improves, but device complexity and cost increase
Solution Approach 1:
The ground transmitters serve multiple functions: they act as positioning reference points, provide navigation guidance, and enable velocity measurement through signal Doppler shift analysis. This multi-functionality reduces the need for separate specialized devices for each function, thereby reducing overall system complexity despite the addition of ground infrastructure.
Solution Approach 2:
The system uses the drone's own receiver and onboard computer to process signals and calculate position, eliminating the need for external marking systems on the drone itself. The ground-based infrastructure provides the service, and the drone's existing sensors and processors self-service the positioning calculation without requiring additional complex onboard hardware.
3Measurement precision
If position identification is performed continuously on all coordinate axes, then positioning accuracy is maintained, but processing load and power consumption increase
Solution Approach 1:
The system performs partial position identification by focusing computational resources on the primary coordinate axis (flight direction) where continuous monitoring is critical, while using less frequent or estimated updates for secondary axes. This partial action approach maintains sufficient positioning accuracy for safe operation while significantly reducing the processing load and power consumption compared to continuous full-axis monitoring.
Solution Approach 2:
Instead of continuous position identification on all axes, the system uses periodic updates at strategically determined intervals. The ground transmitter sends signals at specific periods, and the drone processes position calculations periodically rather than continuously, reducing computational burden and power consumption while maintaining positioning accuracy through adequate sampling frequency.
Data Source
AI summary
The present invention aims to control position of flying object with respect to a structural object in a situation where it is difficult to perform positioning based on radio signals transmitted from a satellite. A position identification unit identifies position of flying object in troublesome GPS signal reception space, using different methods for coordinate axes. Specifically, position identification unit identifies position, on Z axis (first coordinate axis), of flying object in troublesome GPS signal reception space, based on distance from flying object to structural object (distance measured at time of position identification), and identifies positions, on X and Y axes (second coordinate axes), of flying object based on change in shape of structural object in respective axis directions of X and Y axes (second coordinate axes) (history of distance from flying object to bridge B measured multiple times until position identification).