Reactive image-based collision avoidance system for unmanned aircraft systems
Degen, Shane C. (2011) Reactive image-based collision avoidance system for unmanned aircraft systems. Masters by Research thesis, Queensland University of Technology.
Approximately 20 years have passed now since the NTSB issued its original recommendation to expedite development, certification and production of low-cost proximity warning and conflict detection systems for general aviation . While some systems are in place (TCAS ), ¡¨see-and-avoid¡¨ remains the primary means of separation between light aircrafts sharing the national airspace. The requirement for a collision avoidance or sense-and-avoid capability onboard unmanned aircraft has been identified by leading government, industry and regulatory bodies as one of the most significant challenges facing the routine operation of unmanned aerial systems (UAS) in the national airspace system (NAS) [3, 4]. In this thesis, we propose and develop a novel image-based collision avoidance system to detect and avoid an upcoming conflict scenario (with an intruder) without first estimating or filtering range. The proposed collision avoidance system (CAS) uses relative bearing ƒÛ and angular-area subtended ƒê , estimated from an image, to form a test statistic AS C . This test statistic is used in a thresholding technique to decide if a conflict scenario is imminent. If deemed necessary, the system will command the aircraft to perform a manoeuvre based on ƒÛ and constrained by the CAS sensor field-of-view. Through the use of a simulation environment where the UAS is mathematically modelled and a flight controller developed, we show that using Monte Carlo simulations a probability of a Mid Air Collision (MAC) MAC RR or a Near Mid Air Collision (NMAC) RiskRatio can be estimated. We also show the performance gain this system has over a simplified version (bearings-only ƒÛ ). This performance gain is demonstrated in the form of a standard operating characteristic curve. Finally, it is shown that the proposed CAS performs at a level comparable to current manned aviations equivalent level of safety (ELOS) expectations for Class E airspace. In some cases, the CAS may be oversensitive in manoeuvring the owncraft when not necessary, but this constitutes a more conservative and therefore safer, flying procedures in most instances.
Impact and interest:
Citation counts are sourced monthly from and citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||QUT Thesis (Masters by Research)|
|Supervisor:||Mejias Alvarez, Luis, Ford, Jason , Gonzalez, Luis F., & Walker, Rodney|
|Keywords:||collision avoidance, unmanned aircaft systems, unmanned aerial vehicles, uninhabited aerial systems, UAS, UAV, image-based visual servoing, sense and avoid, see and avoid, sense and act, obstacle avoidance, collision risk, guidance, control, gimballed camera, nonlinear aircraft control, control and simulation, MATLAB, Monte Carlo simulation, equivalent level of safety, ELOS, national airspace system, feature based manoeuvring, position-based avoidance, intruder alert, bearings-only tracking|
|Divisions:||Current > Research Centres > Australian Research Centre for Aerospace Automation
Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
|Institution:||Queensland University of Technology|
|Deposited On:||10 Nov 2011 23:54|
|Last Modified:||10 Nov 2011 23:54|
Repository Staff Only: item control page