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In this work, we propose a path planning method for a fleet of a fixed wing UAVs. This online 3D method is based on the artificial potential field (APF) to calculate the necessary controls for each agent in the formation. To do that, we propose a model of potential field that takes into account the formation of the fleet of UAVs. We propose, also, a geometric model of the formation. Simulation results...
Formal verification of industrial systems is very challenging, due to reasons ranging from scalability issues to communication difficulties with engineering-focused teams. More importantly, industrial systems are rarely designed for verification, but rather for operational needs. In this paper we present an overview of our experience using hybrid systems theorem proving to formally verify ACAS X,...
The problem of optimal multi-criteria conflict avoidance between multiple unmanned aerial vehicles is considered. The procedure of sequential synthesis of the conflict-free flight trajectories using multi-criteria dynamic programming has been developed. Selection of the optimal combination of conflict-free trajectories is performed using linear convolutions of optimality criteria
We consider the design of a barrier regulator — a special regulator, which tries to minimize the effect of state-space constraints violation in dynamical systems, creating a soft barrier in their state space. We employ a time-suboptimal predictive control strategy for discrete-time linear systems based on the minimization of a polyhedral distance function. Computationally, our approach reduces to...
Airborne network plays an important role in operations of Air Force. Due to the rapidly-changing topologies, limited wireless communication spectrum, latency, and priorities of tasks, it is vitally important to have dynamic spectrum management between aircrafts and base station in airborne networks. Particularly, we encounter two major challenges: (1) uncertainty about channel quality, in terms of...
With increasing numbers of air traffic, and new kinds of air traffic emerging, new strategies are being developed in air traffic management to guarantee the safety of air traffic. Decision support tools in operation today barely extend beyond safety net features providing last-minute alerts for evasive actions. Tools with a greater time horizon to facilitate timely and gentle corrective action are...
This paper addresses the air traffic control problem of conflict detection and resolution (CDR) under intent uncertainty, in a multiple model (MM) trajectory information processing framework. The conflict detection is based on a predicted probability of conflict. The problem of conflict resolution (CR) is formulated as one of a chance-constrained model predictive control, whereby the constraint is...
We consider the detection component of a conflict detection and resolution system for air traffic management. A conflict is an event of a close encounter between two aircraft in the near future. The collision alert system has to balance between declaring alerts timely to true threats and reducing the false alarms. We compare two conflict detection schemes, namely, geometric and probabilistic method,...
In military environment an operator needs to evaluate the tactical environments in real-time and make decisions to protect the assets against the enemy threats by selecting the appropriate means to engage the enemy target. This work is related to the reconnaissance (including the automatic identification and classification) of targets with hostile behaviors in relation to one point of interest located...
Synthetic aperture radar (SAR) processing techniques and approaches, which are required for the operation under unstable flight conditions, are described in the paper, including frame-based data processing, compensation of motion errors, and autofocusing. Performance of the methods is illustrated on radar data obtained with Ku-band and X-band airborne SAR systems.
Recently increasing attention has been paid to multirotor small-scale autonomous helicopters. The most studied rotor layout is the so-called quadrotor helicopter, also called quadcopter. However, these UAVs can be seen as lacking agility as they cannot move in their horizontal plane and thus have to rotate to perform translations. In this work, we develop on a layout involving only three rotors with...
This paper presents a new development of collision avoidance algorithm that ensures an Unmanned Aerial Vehicle (UAV) can avoid multiple intruders autonomously. Firstly, the Markov Decision Process (MDP) based approach generates the multiple threats resolution logic for the collision avoidance system. Secondly, the optimal trajectory is smoothed by the differential flatness technique where the constraints...
Bearing in mind the risks aviation industry is facing recently, this paper proposes a wind field estimation formulation for an F-16 fighter aircraft. Focus of the work is two-fold. A lateral-directional, non-linear guidance controller is developed first to ensure tight ground track control without violating saturation limits of bank angles. For trajectory tracking, path following vectorial computations...
This paper studies the geometric pseudospectral method, which refers to the Gauss pseudospectral method that is extended to the special Euclidean group SE(3) for UAVs trajectory planning. On SE(3), a complete left invariant rigidbody dynamical UAV model is established in a body-fixed frame, including kinematical and dynamical models. For the kinematical model, the equivalent Lie algebra equation corresponding...
It is very important for searcher to predict the lost plane falling rang. The motion equation of lost plane is built with additional mass and random force, and solved by using difference method abd random number, the trajectory is calculated by using integral method, the lost plane falling rang is determined by using probability distribution contour map.
GR-strip (Geography-Referenced stripmap) imaging mode is a new imaging mode of SAR (Synthetic Aperture Radar), it is very different from the normal stripmap imaging mode. Operating in this mode, trajectory of aircraft can be un-parallel to swath, thus a higher flexibility is obtained due to the reduces of limitation for radar trajectory. Meanwhile, the characteristic of unlimited swath in azimuth...
Reference governors enforce pointwise-in-time state and control constraints by temporarily modifying the reference command to a nominal closed-loop system whenever the danger of constraint violation exists. In this paper we propose a reference governor with the added capability of resetting internal closed-loop system states as necessary to avoid constraint violation. With this approach the constrained...
This paper addresses the active target defense differential game where an Attacker missile pursues a Target aircraft. A Defender missile is fired by the Target's wingman in order to intercept the Attacker before it reaches the aircraft. Thus, a team is formed by the Target and the Defender which cooperate to maximize the distance between the Target aircraft and the point where the Attacker missile...
The UAV (Unmanned Aerial Vehicles) they have demonstrated their enormous capabilities in military and civilian applications in recent years. They have become an indispensable tool in the field of defense, security and support for the development of a nation. Similarly, the technological development has allowed these aircraft to fly autonomously thanks to electronic control systems called autopilots...
This paper details the design and performance assessment of a unique collision avoidance decision and control strategy for autonomous vision-based See and Avoid systems. The general approach revolves around re-positioning a collision object in the image using image-based visual servoing, without estimating range or time to collision. The decision strategy thus involves determining where to move the...
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