Multi-stage UAV Landing Detection System
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Solution Overview
Problem
Existing landing detection systems for UAVs face challenges with accuracy due to aerodynamic ground effects, GPS signal deterioration, and sensor saturation, leading to false or missed detections, which can result in unsafe disarmments.
Innovation Solution
Implementing a multi-stage landing detection method that includes static, thrust, shock, and free-fall tests, where a UAV is deemed landed only after passing multiple tests to ensure accurate detection and avoid false positives, thereby safely disarming the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single landing detection test is used, then the system complexity is low, but the detection accuracy and reliability are insufficient due to false or missed detections
Solution Approach 1:
The landing detection system is divided into multiple independent detection tests: barometric pressure test, GPS test, accelerometer test, and shock test. Each test independently evaluates a specific aspect of landing conditions, and their results are combined to make the final landing determination. This segmentation allows each test to focus on specific parameters, improving overall reliability while maintaining manageable complexity through modular design.
2Measurement precision
If barometer data is used for landing detection, then altitude information is available, but aerodynamic ground effects cause false readings near the ground
Solution Approach 1:
The system uses multiple intermediate detection mechanisms (GPS position data, accelerometer readings, shock detection) to verify landing conditions alongside barometric pressure data. These intermediary tests help distinguish between actual landings and false barometric readings caused by aerodynamic ground effects, as they measure different physical phenomena that are less susceptible to the same environmental interference.
3Measurement precision
If GPS sensors are used close to the ground, then position data is available, but signal deterioration due to multipath effects reduces accuracy
Solution Approach 1:
The system merges multiple detection methods including barometric pressure, accelerometer data, shock detection, and GPS positioning into a unified landing detection algorithm. By combining these diverse measurement sources, the system compensates for the weaknesses of individual sensors (such as GPS multipath effects) through cross-validation, where agreement among multiple independent tests confirms a true landing event.
4Measurement precision
If accelerometer and gyroscope readings are used to detect landing, then motion data is available, but sensor saturation due to shocks causes missed detections
Solution Approach 1:
The system performs preliminary detection using shock sensors and barometric pressure changes before relying on accelerometer and gyroscope data. By detecting the initial shock event and sustained low-altitude condition first, the system can then interpret subsequent accelerometer readings with contextual knowledge, preventing misinterpretation of saturation artifacts as continued motion when the vehicle has already landed.
5Reliability
If an extended time period is required before setting landed state, then false detections are reduced, but the response time to safely disarm the vehicle is delayed
Solution Approach 1:
The system applies different time thresholds and confidence requirements to different detection tests based on their reliability. High-confidence tests (such as shock detection combined with barometric pressure) can trigger landing state more quickly, while tests prone to false positives require longer verification periods. This partial application of extended verification only where needed maintains safety while reducing overall detection time.
Data Source
AI summary
The disclosure describes systems and methods for detecting an aerial vehicle landing. One method includes performing at least two of a plurality of landing tests to detect the landing of the aerial vehicle. The plurality of landing tests include a static test, a thrust test, and a shock test. Upon a detection of the landing by one of the at least two landing tests performed, the method further includes performing a free-fall test to detect a free fall of the aerial vehicle. The free fall of the aerial vehicle is a change in altitude of the aerial vehicle above an altitude change threshold. Upon a lack of a detection of the free fall by the free-fall test, the method includes setting a landed state for the aerial vehicle. Upon a detection of the free fall by the free-fall test, the method includes setting an in-air state for the aerial vehicle.