High-speed Unmanned Aerial Vehicle Research Articles

Air-to-Ground Wireless Links for High-Speed UAVs

As unmanned aerial vehicles (UAVs) are becoming more popular and the demand for wireless links for UAVs is increasing, it is crucial to develop air-to-ground (A2G) wireless links for high-speed UAVs. Suffering from the high mobility and limitation of transmission power of UAVs, A2G wireless links become unstable to provide high quality communication services. In this paper, we design robust A2G wireless links for high speed UAVs, where conjunct power control is developed together with switched beamforming to maximize the power efficiency and minimize the fluctuation of A2G wireless links of millimeter wave (mmWave) signal transmission. We first present channel models for A2G wireless links of high-speed UAVs, which can be virtually seen as multiple-input multiple-output (MIMO) channels. To maximize the power efficiency, a conjunct power control problem is formulated to allocate powers for wireless links between antenna arrays on UAVs and access points (APs). For switched beamforming, beamformers are designed to provide a certain time-invariant signal-to-interference-plus-noise ratio (SINR) to minimize the SINR fluctuation of A2G wireless links. From theoretical analysis and numerical results, it is shown that the proposed architecture is able to provide robust and high quality A2G wireless links for high-speed UAV communication systems.

Research Progress of Anti-jamming Technology of Unmanned Aerial Vehicle(UAV) Data Link

An high-speed stealth UAV will be developed by an aviation research institute. Data link is an important part of UAV system. In order to have a deeper understanding of data link system, this paper was made through studying many recent academia papers. The basic composition and working principle of UAV data link system was introduced in this paper, the current UAV data link interference and anti-interference technology was expounded, the key problems faced by the development of UAV data link anti-interference technology were summarized, and the future development trend of UAV data link anti-interference technology was pointed out.

Dynamics and Directional Stability of High-Speed Unmanned Aerial Vehicle Ground Taxiing Process

The bifurcation analysis method is used to study the high-speed unmanned aerial vehicle (UAV) dynamics and directional stability during the steering process on the ground. A UAV nonlinear ground taxiing dynamic model is built considering the effects of large-angle-steering motion on the interactive aerodynamic forces. The single-parameter bifurcation analysis is first conducted to study the influence of the UAV rectilinear velocity on the system stability performance. The bifurcation parameter plane is divided into several parts by the bifurcation points to analyze different kinds of UAV steering motion states. Then the analysis of the UAV loading features and the kinetic characteristics gives further insight into the instability mechanism of the system. Moreover, the dual-parameter bifurcation analysis is carried out, and the effects of the main-wheel span and the nose wheel steering angle are investigated. Results indicate that the Bautin bifurcation and the Fold-Hopf bifurcation both increase the unstable region of the UAV ground steering dynamic system.

Research on Roll Attitude Control of UAV Based on Active Disturbance Rejection Control

The roll attitude control of small high-speed unmanned aerial vehicle (UAV) is very difficult compared to the conventional low-speed UAV. The dynamic pressure is large and the moment of inertia is too small, which cause the aileron is sensitive to manipulation. The roll attitude may oscillate due to the actuator rate limiting. In response to this feature, the active disturbance rejection control (ADRC) is added to compensate the nonlinear part of the system, so that the system is close to an integral link. The problem of the actuator rate limiting can be solved by tuning the gain of the angular rate control to change the system bandwidth. On the other hand, the rolling motion is, in general, coupled from the yawing and sideslip motions. ADRC can decouple the roll channel and the yaw channel, solving the nonlinear problem of control. Combination with the requirements of frequency and time domain, design the roll attitude controller. The UAV nonlinear simulation results show that the roll attitude control based on ADRC meets the flight control requirements.

An Integrated Adaptive Kalman Filter for High-Speed UAVs

In order to solve the problems of filtering divergence and low accuracy in Kalman filter (KF) applications in a high-speed unmanned aerial vehicle (UAV), this paper proposed a new method of integrated robust adaptive Kalman filter: strong adaptive Kalman filter (SAKF). The simulation of two high-dynamic conditions and a practical experiment were designed to verify the new multi-sensor data fusion algorithm. Then the performance of the Sage–Husa adaptive Kalman filter (SHAKF), strong tracking filter (STF), H∞ filter and SAKF were compared. The results of the simulation and practical experiments show that the SAKF can automatically select its filtering process under different conditions, according to an anomaly criterion. SAKF combines the advantages of SHAKF, H∞ filter and STF, and has the characteristics of high accuracy, robustness and good tracking skill. The research has proved that SAKF is more appropriate in high-speed UAV navigation than single filter algorithms.

Development of Mobile Ground Control System and GPS Base Auto Tracking Antenna

Flight test of both rocket and high speed Unmanned Aerial Vehicle (UAV), which is currently developed by LAPAN, can not be separated from the need for a monitoring system of all the attitude of the vehicles. Utilizing and combining some of the available equipment components into a ground control system (GCS) equipped with GPS based auto tracking antenna, makes it easy in previous flight test activities that only do tracking antenna manually. This ground control system is equipped with automatic tracking antenna that always leads to the vehicle, so that the data attitude of flying the vehicle will be maximally monitored and analyzed directly with ease. This system has been tested on a laboratory scale related to testing using hardware in the loop simulation system

Channel estimation for high speed unmanned aerial vehicle with STBC in MIMO radio links

This paper proposes a channel estimation method based on Kalman filter and adaptive estimation with space-time block code (STBC) and multiple antenna systems [multiple input single output (MISO) and multiple input multiple output (MIMO)\ for high speed UAVs. Simulations have been done in time-varying Rayleigh faded channels for BPSK and QPSK. The proposed technique shows a very good error for severely faded channels. Application of Alamouti STBCs with diversity based on multiple antennas provides improved performance in faded wireless channels. Alamouti transmit diversity scheme, however, relies on the availability of accurate channel state information (CSI) for unmanned aerial vehicles (UAVs). Simulation results show that our proposed method achieves accurate estimation for the SNR and Doppler shift in a wide range of velocities and SNRs.

Channel estimation for high speed unmanned aerial vehicle with STBC in MIMO radio links

This paper proposes a channel estimation method based on Kalman filter and adaptive estimation with space-time block code (STBC) and multiple antenna systems [multiple input single output (MISO) and multiple input multiple output (MIMO) for high speed UAVs. Simulations have been done in time-varying Rayleigh faded channels for BPSK and QPSK. The proposed technique shows a very good error for severely faded channels. Application of Alamouti STBCs with diversity based on multiple antennas provides improved performance in faded wireless channels. Alamouti transmit diversity scheme, however, relies on the availability of accurate channel state information (CSI) for unmanned aerial vehicles (UAVs). Simulation results show that our proposed method achieves accurate estimation for the SNR and Doppler shift in a wide range of velocities and SNRs.

Low ICI Symbol Boundary Alignment for 5G Numerology Design

Symbol boundary alignment, with respect to waveform selection, has an important impact on the numerology design for fifth-generation mobile applications. The current symbol boundary alignment, along with orthogonal frequency division multiplexing (OFDM) waveform, strongly suffers from intercarrier interference (ICI) especially in unmanned aerial vehicles (UAV) communications. This happens when the mobility causes Doppler effect which results in loss of orthogonality in OFDM. The available solutions for overcoming the ICI problem suffer from high complexity, low spectral efficiency, and incompatibility with the current radio access technologies. This paper presents a novel symbol boundary alignment, called Low ICI Symbol (LICIS) boundary alignment numerology, to avoid the disadvantages of the available solutions. LICIS utilizes large subcarrier-spacing to reduce the ICI power (e.g., around 5-dB ICI power reduction with subcarrier spacing of 30 kHz in high-speed UAV communications). Moreover, LICIS is based on the same reference clock as local thermal equilibrium (LTE) which guarantees its compatibility with the current LTE numerology. In addition, this approach places only one guard-interval at the end of a sequence of OFDM symbols and creates a subslot. This leads to less overhead and preserves the spectral efficiency. Furthermore, a pre-fast Fourier transform (FFT) multipath channel equalizer is considered for removing the intersymbol interference between the OFDM symbols occurring within the subslot. Only one additional FFT and IFFT operations are required for the equalizer which creates an acceptable complexity increment compared to the complexity of other available solutions. Numerical and analytical evaluations show the superior performance of the proposed technique in terms of reliability and spectral efficiency

Синтез управления маневром уклонения беспилотного летательного аппарата с учетом терминальных ограничений

Introduction. The solution to the problem of development of suboptimal evasive strategy of unmanned aerial vehicle (UAV) under the conditions of uncertainty of the current motion characteristics, and the future behavior strategy of the interdictor is considered. The FV (flying vehicle) control is organized with maximum efficiency. Herewith, the maneuvering FV trajectory must satisfy the requirements of optimality for some given functions of the phase variables at the final time and the conditions of its path through a specified terminal area space. The initial conditions and the dynamic facilities of the evading and opposing FV at the initial time are assumed to be known. The evading FV control is developed by its onboard guidance and navigation system in real time on nonlinear position feedback control. The work objective is to build an algorithm for solving the problem of synthesis of terminal optimal control of motion of center of mass of highspeed UAV that allows searching for the optimal control in function of the current coordinates of the object. Consideration of the problem in this formulation distinguishes it from the classical conflict tasks on the prosecution to be solved with the involvement of the theory of differential games, and demands computationally efficient solution methods. Materials and Methods. For the UAV operating under the conditions of violent disturbances, the most effective hard constraints on the phase variables and control are the so-called methods of optimal terminal control that implement adaptive algorithms with projection. Therefore, the solution to the formulated problem can be obtained precisely with the use of their ideology. Research Results. A new method of piecewise-software terminal control of the UAV motion is developed. It differs from the known ones in that it is based on the procedure of searching a control strategy upon the best guaranteed result with the terminal restrictions. A methodology for calculating the management strategy for the FV evasive maneuver in a slow loop of the terminal control system is worked out. It is characterized in that instead of the forecast procedure in speed-up time and calculation of residuals, the conversion of a boundary value problem to a one-point task of integration of the ordinary differential equations system with account for the occurrence of non-zero terminal member in the cost functional, is used. Discussion and Conclusions. Despite the fact that the development of a suboptimal guidance strategy in the terminal area of the evading FV is not in the form of synthesis, the control software adapts to the current conditions. This is achieved through the iterative procedures of regular recalculation of terminal conditions that are equivalent to the periodic circuit feedback. Thus, the evading FV is brought to a specified terminal area through software, while evading an interdictor is developed as synthesis. Limitations to the method are the terms that the movement model of the opposing FV is known, and it forms a natural control of the evader intercept.

DFM: A Distributed Flocking Model for UAV Swarm Networks

Flocking of the unmanned aerial vehicle (UAV) network refers to utilize the node’s autonomous mobility to satisfy the principle of cohesion, separation, and alignment. A network with flocking ensures the connectivity between high-speed UAV nodes and simplifies the design of various swarm applications. In this paper, we propose a novel distributed flocking model for UAV swarm networks. The model follows the Boid principle and establishes the master–slave transmission mode among the nodes. The slave node performs the distributed autonomous regulation. An effective flocking method is proposed, which is based on the positioning and communication capabilities of Wi-Fi. The slave node can sense and adjust their distance and direction from the master node. The simulation and experimental results show that our model can guarantee the connectivity between all nodes and has $1.4\times $ the network goodput gain outperforms the traditional flying ad hoc network.

Design and Analysis of High-Speed Unmanned Aerial Vehicle Ground Directional Rectifying Control System

Design and Analysis of High-Speed Unmanned Aerial Vehicle Ground Directional Rectifying Control System