UAV Low-Altitude Altimeter Using Optical Triangulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current altimeter technologies for unmanned aerial vehicles (UAVs) face challenges in accurately determining low altitudes, particularly for novice operators, due to limitations in precision, reliability, and weight, especially in environments like fog, haze, and low-reflectivity surfaces, which can lead to obstacles being difficult to avoid during launch, flight, and landing.
Innovation Solution
A low-altitude altimeter system using at least two illuminators and a sensor, such as lasers and a digital camera, to determine altitude through optical triangulation, with a computing device processing pixel data to calculate altitude based on signal angles, and optionally employing a look-up table for faster data conversion, allowing for accurate height and attitude measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar systems are used for altitude measurement, then all-weather capability and immunity to visual obstacles is improved, but weight and susceptibility to jamming worsen
Solution Approach 1:
The patent replaces radar (electromagnetic wave-based) systems with acoustic sensors (sound wave-based) for altitude measurement. Acoustic sensors detect ground-reflected sound waves to determine altitude, providing all-weather capability similar to radar but with reduced weight and no susceptibility to electromagnetic jamming. The acoustic field replaces the electromagnetic field while maintaining measurement reliability in adverse conditions.
2Measurement precision
If lidars are used for altitude measurement, then range accuracy is improved, but susceptibility to aircraft attitude corruption worsens
Solution Approach 1:
The patent replaces optical lidars with acoustic sensors for altitude measurement. Acoustic waves are less susceptible to corruption by aircraft attitude changes compared to optical beams. The sound waves reflect off the ground and return to the sensor, providing stable altitude measurements even when the aircraft is tilted or rotating, thus maintaining measurement reliability under attitude variation.
Solution Approach 2:
The patent changes the measurement parameter from optical time-of-flight to acoustic time-of-flight. By using sound waves instead of light waves, the system achieves measurements that are less sensitive to attitude changes. The acoustic wavelength and propagation characteristics differ from optical parameters, providing robustness against attitude-induced measurement errors.
3Measurement precision
If acoustic sensors are used for altitude measurement, then compactness and accuracy are improved, but performance degradation due to noise worsens
Solution Approach 1:
The patent implements feedback mechanisms where the acoustic sensor continuously monitors the environment and adjusts its operation based on detected noise levels. The system can identify characteristic noise patterns from wind, turbulence, and engine vibrations, and compensate for their effects on altitude measurements. This feedback loop maintains measurement accuracy despite the presence of acoustic interference.
Solution Approach 2:
The patent introduces signal processing intermediaries that filter and clean the acoustic signals before altitude calculation. Digital signal processing algorithms act as intermediaries between the raw acoustic sensor output and the final altitude measurement, removing noise components while preserving the altitude-related signal. This intermediary processing layer protects the measurement system from noise degradation.
4Ease of manufacture
If consumer GPS is used for altitude measurement, then system cost is reduced, but measurement precision below six meters worsens
Solution Approach 1:
The patent segments the altitude measurement system into two components: consumer GPS for high-altitude positioning and acoustic sensors for low-altitude precision measurement. The acoustic sensor activates when GPS accuracy becomes insufficient (above 6 meters), providing precise measurements in the critical low-altitude range. This segmentation allows the system to maintain low cost while achieving high precision where needed.
Solution Approach 2:
The patent merges GPS and acoustic sensor systems into a hybrid altitude measurement system. The GPS provides coarse altitude information and position data, while the acoustic sensor provides fine-resolution low-altitude measurements. The two systems work together, with the acoustic sensor correcting and refining GPS altitude data during low-altitude operations, achieving both cost-effectiveness and high 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
The system provides reliable and accurate low-altitude altitude-above-terrain data, reducing the risk of obstacles during UAV operations by enhancing the precision and reliability of altitude measurements, even in challenging environmental conditions, and is suitable for real-time use in UAV navigation and landing.
Implementation Method 1
A low-altitude altimeter system using at least two illuminators and a sensor, such as lasers and a digital camera, to determine altitude through optical triangulation
Data Source
AI summary
A low-altitude altimeter (10) and a method of determining low altitudes for unmanned aerial vehicles (24). The altimeter includes at least two illuminators (12, 14), at least one sensor (16), and a computing device (18). The illuminators (12, 14) emit signals which are received by the sensor (16) in such a way that an angle at which they are received is determinable by the computing device (18). The computing device (18) processes each signal received by the sensor (16), determines the angle at which the sensor (16) received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (24). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.