UAV Crop Height Measurement Using Barometric and SONAR Sensing
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Solution Overview
Problem
Conventional methods for automatically measuring crop height and characteristics, such as those using UAVs with image analysis or LIDAR systems, are either error-prone or require expensive and bulky equipment, making them unsuitable for low-cost UAVs.
Innovation Solution
A method and system utilizing a low-cost UAV equipped with a barometric pressure altimeter and SONAR sensor to determine crop height by calculating the difference between the UAV's elevation and the distance to the ground surface, with optional wind correction, allowing for accurate and cost-effective measurement of crop characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LIDAR systems are used on UAVs to measure crop height, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The measurement system is segmented into two independent components: a barometric altimeter for measuring UAV elevation and a SONAR sensor for measuring distance to crop tops. This segmentation allows each sensor to operate independently within its optimal range, achieving accurate crop height measurement without requiring complex integrated systems like LIDAR.
Solution Approach 2:
The patent introduces an intermediary calculation method where crop height is derived as the difference between altimeter elevation and SONAR distance measurements. This intermediary approach uses simple, low-cost sensors combined with computational processing to achieve measurement precision previously only available from expensive LIDAR systems.
2Adaptability or versatility
If image analysis is used to construct three-dimensional models for crop height estimation, then measurement capability is improved, but measurement precision deteriorates due to noticeable error
Solution Approach 1:
The patent replaces optical/image-based measurement systems with acoustic and pressure-based sensing systems. The SONAR sensor uses sound wave propagation to measure distance directly, while the barometric altimeter uses atmospheric pressure to determine elevation, substituting the indirect optical triangulation method with direct physical measurements that yield higher precision.
3Device complexity
If standard equipment on low cost UAVs is used, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent demonstrates that standard, multi-functional equipment already present on low-cost UAVs (barometric altimeter for navigation and SONAR for obstacle avoidance) can be repurposed for precise agricultural measurement. This universal application of existing sensors eliminates the need for specialized expensive equipment while maintaining measurement precision.
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 accurate and efficient measurement of crop height and characteristics using standard equipment on low-cost UAVs, reducing errors and operational costs while maintaining robustness against elevation changes and wind effects.
Implementation Method 1
collecting first data that indicates an elevation of the UAV with a barometric pressure based altimeter of the UAV
Implementation Method 2
collecting second data with a Sound Navigation and Ranging (SONAR) sensor of the UAV that indicates a distance to a nearest object on the ground surface
Data Source
AI summary
A method and apparatus for automatically determining a characteristic of a crop using an unmanned aerial vehicle (UAV) includes operating the UAV at an elevation above a ground surface of a field and collecting first data that indicates an elevation of the UAV with a barometric pressure based altimeter of the UAV. Second data is collected with a SONAR sensor of the UAV that indicates a distance to a nearest object on the ground surface. The SONAR sensor has a SONAR sensor range and the elevation above the ground surface is less than the SONAR sensor range. The method further includes receiving the first data and the second data on a processor, and determining a height of the nearest object above the ground surface with the processor based on the first data and second data. Output data that indicates the height of the nearest object is presented on a display.