In this paper the quadrotor dynamic model with nonlinear inputs is presented. Deadzone and saturation nonlinear inputs are considered for the quadrotor reflected to the actuators. The goal is to obtain a faithful mathematical representation of the mechanical system for system analysis and control design, not only in hover as presented in many works, but also in motion when take-off, land and flight for aerial navigation task. The model was implemented in Matlab/Simulink simulation model to optimize the design and to project control. Simulations of the model show that the nonlinear inputs must be considered in the control project.

This paper presents a communication network for a squadron of unmanned aerial vehicles (UAVs) to be used in the scanning rocket impact area for Barreira do Inferno Launch Center—CLBI (Rio Grande do Norte, Brazil), aiming at detecting intruder boats. The main features of communication networks associated with multi-UAV systems are presented. This system sends information through Wireless Sensor Networks (WSN). After comparing and analyzing area scanning strategies, it presents the specification of a data communication network architecture for a squadron of UAVs within a sensor network using XBee Pro 900HP S3B modules. A brief description is made about the initial information from the construction of the system. The embedded hardware and the design procedure of a dedicated communication antenna to the XBee modules are presented. In order to evaluate the performance of the proposed architecture in terms of robustness and reliability, a set of experimental tests in different communication scenarios is carried out. Network management software is employed to measure the throughput, packet loss and other performance indicators in the communication links between the different network nodes. Experimental results allow verifying the quality and performance of the network nodes, as well as the reliability of the communication links, assessing signal received quality, range and latency.

In this paper the hexarotor dynamic model with nonlinear inputs and full state back stepping technique is presented. Dead zone and saturation nonlinear inputs are considered reflected to the rotors. The goal is to obtain a faithful mathematical representation of the mechanical system for analysis and control design, not only in hover, but also in motion when take-off, land and flight for aerial navigation tasks. The model was implemented in Matlab/Simulink to optimize the design of control system. Simulations of the hexarotor model shows the performance of the control law and stabilizes with good tracking.

The use of unmanned aerial vehicles (UAV) to provide services such as the Internet, goods delivery, and air taxis has become a reality in recent years. The use of these aircraft requires a secure communication between the control station and the UAV, which demands the characterization of the communication channel. This paper aims to present a measurement setup using an unmanned aircraft to acquire data for the characterization of the radio frequency channel in a propagation environment with particular vegetation (Caatinga) and a lake. This paper presents the following contributions: identification of the communication channel model that best describes the characteristics of communication; characterization of the effects of large-scale fading, such as path loss and log-normal shadowing; characterization of small-scale fading (multipath and Doppler); and estimation of the aircraft speed from the identified Doppler frequency.