In this paper, an onboard vision-based system for the autonomous landing of a low-cost quadrotor is presented. A novel landing pad with different optical markers sizes is carefully designed to be robustly recognized at different distances. To provide reliable pose information in a GPS (Global Positioning System)-denied environment, a vision algorithm for real-time landing pad recognition and pose estimation is implemented. The dynamic model of the quadrotor is established and a system scheme for autonomous landing control is presented. A series of autonomous flights have been successfully performed, and a video of the experiment is available online. The efficiency and accuracy of the presented vision-based system is demonstrated by using its position and attitude estimates as control inputs for the autonomous landing of a self-customized quadrotor.

Unmanned Aerial Vehicles (UAVs) have recently shown great performance collecting visual data through autonomous exploration and mapping, which are widely used in reconnaissance, surveillance, and target acquisition (RSTA) applications. In this paper, we present an onboard vision-based system for low-cost UAVs to autonomously track a moving target. Real-time visual tracking is achieved by using an object detection algorithm based on the Kernelized Correlation Filter (KCF) tracker. A 3-axis gimbaled camera with separate Inertial Measurement Unit (IMU) is used to aim at the selected target during flights. The flight control algorithm for tracking tasks is implemented on a customized quadrotor equipped with an onboard computer and a microcontroller. The proposed system is experimentally validated by successfully chasing a ground and aerial target in an outdoor environment, which has proven its reliability and efficiency.

In recent years, cooperative multi-UAV systems have shown great performance in a variety of potential applications. Aiming at the problem of fixed-wing UAVs cooperative formation flight, this paper presents a low-cost system based on Pixhawk autopilot for keeping the shape of the formation. The kinematic relationship of a leader-follower UAV formation is established and a fuzzy PID control law is designed for the follower to maintain the expected position relative to the leader. Wireless data transmission between the leader and followers is achieved by using several radio telemetry modules. The proposed formation control system is validated by a series of successful flight experiments using 3 small-scaled UAV models, which has proven its feasibility and reliability.

This paper presents an integrated guidance and control (IGC) law for the strapdown homing missile with consideration of the field-of-view (FOV) constraint and actuator saturation. Given that the commonly-required guidance information, such as the inertial line-of-sight (LOS) angle and/or its angular rate, cannot be measured by the strapdown seeker, a detailed IGC model considering the gravity and timevarying missile velocity is first derived based on the only measurable information, the body-LOS (BLOS) angle. Then a novel IGC controller is designed for this model by means of the integral-type Barrier Lyapunov Function (iBLF) based dynamic surface control technique. This IGC controller following the pure tracking principle is capable of forcing the BLOS angle to track the negative angle of attack while satisfying the FOV constraint and actuator saturation in an integrated manner, thereby guaranteeing a precise attack on a stationary ground target. The stability of closed-loop system and the boundedness of constrained BLOS angle are both proved strictly, and the performance of proposed IGC controller is thoroughly testified by method comparisons and Monte-Carlo analysis. INDEX TERMS Actuator saturation, body-LOS (BLOS) angle, dynamic surface control, FOV constraint, integral-type Barrier Lyapunov Function (iBLF), integrated guidance and control (IGC).

Abstract. Loitering munitions would quickly reach the target area in the complex battlefield environment, and perform a variety of application advantages, such as total field reconnaissance, flexible cruise monitoring, weather monitoring, the battlefield damage assessment, relay communication and target attack, which has attached the widespread attention around the world. In this paper, each functional system model of the typical loitering munitions has been established. With the fact that the loitering munitions are faced with the problem of complex terrain, its launch battlefield environment and launch strategies under different terrain is analyzed and studied. And through the wind tunnel test of aerodynamic characteristics, the dynamic model of a small loitering munition is developed. In a typical topographical environment, based on genetic algorithm, trajectory optimization for a launch loitering munition is accomplished, eschewing the battlefield obstacles, the calculation results have great significance in technical guidance to engineering practices.