Aircraft Heading Research Articles

Complexity analysis of air traffic based on complex networks under TBO mode

Since the complex network constructed according to the unified separation standard does not take into account the differences in the operation of aircraft types, it cannot meet the refined requirements of air traffic complexity analysis under trajectory based operation (TBO). To solve this problem, an air traffic complexity analysis model based on complex networks to distinguish different aircraft types is proposed. Firstly, a calculation model for lateral flight safety intervals of different aircraft types is established, an aircraft precise protection zone is constructed, and the basis for determining the aircraft connection in the flight conflict network is optimized. On the basis of considering information such as aircraft heading and speed, flight conflict judgment pays attention to the different performance and status of aircraft, so that the flight conflict network can be closer to the operation mode of TBO. Through experimental simulation of the TBO operation environment and verification using radar data from Gaoqi Airport, the results show that compared with the previous flight conflict network, the model can refine the horizontal separation standards between aircraft, reduce the complexity of the airspace, reduce the workload of controllers, and improve the operation efficiency of the airspace, and provide more space for aircraft to autonomously select the optimal trajectory.

Swarm Division-Based Aircraft Velocity Obstacle Optimization Considering Low-Carbon Emissions

In the pursuit of sustainable aviation, this paper presents an innovative approach that adopts a swarm division strategy to enhance and refine the velocity obstacle (VO) method, guided by a low-carbon principle. A dynamic elliptical protection zone model forms the core of this innovative approach. Specifically, this dynamic elliptical protection zone is created based on the difference in aircraft velocity, and a swarm division strategy is introduced in this process. Initially, aircraft that share the same route and type, and have similar velocities and distances, are grouped into swarms. Then, the characteristics of the swarms, such as mass points, velocities, and protection zones, are recorded. Second, the collision cone (CC) between swarms is established, and planar geometrical analysis is used to determine the optimal relief velocity and heading of aircraft on the low-carbon objective while ensuring a safe interval between aircraft in the swarm during the relief period. Additionally, a swarm control algorithm is utilized to adjust the velocity of the aircraft by a small margin. Finally, simulation experiments are conducted using Python, revealing that the swarm relief efficiency of the enhanced VO method sees a notable increase of over 33%. Concurrently, the need for adjustments decreases by an average of 32.78%, while fuel savings reach as high as 70.18%. The strategy is real-time and operational, significantly reduces the air traffic controller (ATC) workload, improves flight efficiency and safety, and contributes positively to the reduction in carbon emissions, which is beneficial for the environment.

FORMATION OF WORLDVIEW AND PROFESSIONAL ORIENTATIONS OF AIRCRAFT DESIGNER O. ANTONOV

The article provides a thorough comparative and historical analysis of the process of formation of worldview and professional guidelines in the activities of Oleg Antonov, a prominent master of the national aircraft construction and design industry. In particular, the author, based on numerous biographical materials, highlights certain issues of shaping the worldview of the future founder of the aviation industry in his early youth, outlines the range of interests and hobbies related to Oleg Antonov's own beliefs and the influence of his immediate environment.The author highlights the initial steps of Oleg Antonov's amateur activities towards the creation of the first aircraft, in particular, his participation in the «club of aviation amateurs» organized by him in Saratov in his youth. The first experience of the future aircraft designer's participation in the second All-Union glider rally in the Crimea and his confirmation in choosing his future profession are highlighted.The author emphasizes the importance of Oleg Antonov's fateful meetings in his youth with future prominent spacecraft and aircraft designers S. Korolev, S. Ilyushin, and test pilots S. Anokhin and K. Arceulov.The author points out that despite the failure in Koktebel due to the fact that the Golub glider did not take off due to certain design flaws, O. Antonov used this experience as a springboard to the big world of aircraft construction, taking into account all his mistakes and embarking on the path of improving and modernizing the models he had already created. This event can be classified as the starting point of the national gliding industry and Oleg Antonov's professional growth.The author emphasizes that all subsequent aircraft designs by O. Antonov's design bureau were distinguished by their high-tech component and innovative design approaches. The author emphasizes the fact that in his professional activities, O. Antonov solved all the tasks he set with due regard to the laws of aerodynamics, design, strength testing, manufacturability, etc. Such a credo of professionalism was laid down at the initial stage of O. Antonov's formation as an aircraft designer and head of a leading design bureau.

An Efficient Aircraft Conflict Detection and Resolution Method Based on an Improved Reinforcement Learning Framework

With the steady increase of air traffic column, an auxiliary decision tool is required to compensate the operation redundancy deficiency of more sectors of air traffic control. To solve the problem of nonconflict high-density departure and arrival traffic flow, this method is expected to rapidly establish and maintain safe separation with more flexible changing strategies for aircraft heading and speed. This paper proposes an improved reinforcement learning framework to achieve conflict detection and resolution. The proposed framework includes the first development of an air traffic flow model based on a multiagent Markov decision process. The goal reward function was then maximized by improved Monte-Carlo tree search combined with an upper confidence bound tree. Three simulation scenarios were designed for illustrating the improvements of the proposed algorithm, with the results indicating that the algorithm could establish and maintain safe separation between 20 agents in the simplified hexagon-shaped airspace of Huadong, China. Furthermore, the proposed method was demonstrated to reduce the number of conflicts between aircraft agents by up to 26.32% compared to previous research.

RAIH-Det: An End-to-End Rotated Aircraft and Aircraft Head Detector Based on ConvNeXt and Cyclical Focal Loss in Optical Remote Sensing Images

In airport ground-traffic surveillance systems, the detection of an aircraft and its head (AIH) is an important task in aircraft trajectory judgment. However, accurately detecting an AIH in high-resolution optical remote sensing images is a challenging task due to the difficulty in effectively modeling the features of aircraft objects, such as changes in appearance, large-scale differences, complex compositions, and cluttered background. In this paper, we propose an end-to-end rotated aircraft and aircraft head detector (RAIH-Det) based on ConvNeXt-T (Tiny) and cyclical local loss. Firstly, a new U-shaped network based on ConvNeXt-T with the same performance as the Local Vision Transformer (e.g., Swin Transformer) is presented to assess the relationships among aircraft in the spatial domain. Then, in order to enhance the sharing of more mutual information, the extended BBAVectors with six vectors captures the oriented bounding box (OBB) of the aircraft in any direction, which can assist in head keypoint detection by exploiting the relationship between the local and overall structural information of aircraft. Simultaneously, variant cyclical focal loss is adopted to regress the heatmap location of keypoints on the aircraft head to focus on more reliable samples. Furthermore, to perform a study on AIH detection and simplify aircraft head detection, the OBBs of the “plane” category in the DOTA-v1.5 dataset and the corresponding head keypoints annotated by our volunteers were integrated into a new dataset called DOTA-Plane. Compared with other state-of-the-art rotated object and keypoint detectors, RAIH-Det, as evaluated on DOTA-Plane, offered superior performance.

Research on Drag Reduction and Heat Prevention of Hypersonic Vehicle Combined Model with Reverse Jet and Slot Blowing

A novel strategy combining reverse jet with slotted blowing is proposed in this paper, and two-dimensional (RANS) is used to numerically investigate the flow characteristics of a reverse jet. The numerical results show the jet from the aircraft head ejects backward, pushing the shock away and reducing aerodynamic heating and shock wave resistance. The jet from the middle slot ejects backward and the effective solution reduces the viscous resistance of the fuselage. This new strategy not only further reduces the total resistance but also provides good thermal protection for the aircraft. Compared with the aircraft model, the stagnation point temperature and resistance are reduced by 25.0% and 28.0%, respectively, with the addition of multiple jets.

Automatic Landing for Carrier-Based Aircraft Under the Conditions of Deck Motion and Carrier Airwake Disturbances

This article studies the automatic landing problem for the carrier-based aircraft in the presence of deck motion and carrier airwake disturbance. First, an automatic regressive model based prediction algorithm is proposed to generate the motion information of the deck, which in turn is used to generate corrections in the commands of the aircraft's heading and flight path to guarantee landing accuracy. Then, a fast fixed-time stable system (FFSS) is proposed. Based on the FFSS, the sliding-mode-based command differentiators are designed to estimate the first-order derivatives of the reference commands in finite time. Moreover, using the modified reaching law, the incremental sliding mode control (ISMC) is presented to design the landing guidance and control system to provide fast and accurate flight control to touchdown, where the airwake disturbances are compensated by the designed adaptive super twisting extended state observers (ASTESOs). Besides, to improve the stability during the final approach, an approach power compensation subsystem maintaining the angle of attack is proposed using the ISMC and ASTESO. The stability of the closed-loop system is analyzed using the Lyapunov theorem. Finally, comparative simulation results demonstrate the effectiveness of the proposed control scheme over state-of-the-art methods on the landing accuracy and robustness.

Analysis of quantum scattering characteristics for a cone illuminated with multiphoton in the remote sensing scene

The quantum radar cross sections (QRCS) for the targets are the critical basis for the optimization designs of stealth structures and quantum detection strategy. According to the three-dimensional structure of the conical surface, the one-dimensional Fourier expression of conical multiphoton QRCS in a gradually illuminated area is established using the two-dimensional Fourier expression of QRCS. The advantages of the derived expression in computational complexity are analyzed and verified by simulations. The influence of radius, height, and incident photon numbers on the QRCS for a cone is analyzed. The results show that there are scattering peaks in the center and the direction orthogonal to the side. The scattering peak in the center is proportional to the bottom radius and inversely proportional to the height. In addition, the height mainly affects the side scattering peak, and with the increase in height, the side scattering peak becomes sharp. With the radius increase, the scattering peaks at the center and both sides become sharp. With the increase of incident photon number, the width of scattering main lobe will be narrowed, and the peak difference between main lobe and side lobe will be increased, which indicates that fewer photons are beneficial to the detection of sidelobe, and more photons are beneficial to the detection of the main lobe. This work will help optimize the quantum detection strategy and stealth structure design of the missile and aircraft head, which will provide prior information for research in many fields, such as photonic technology, radar technology, and precision metrology.

THEORETICAL ANALYSIS ON HYPERSONIC MHD SHOCK STAND-OFF DISTANCE OF BLUNT BODY

High speed and shock compression behind the bow shock of an aircraft head result in very high temperature, which would subsequently lead to a conductivity plasma flowfield around the vehicle. The plasma gas provides a direct working environment for the application of magnetic field. The magnetohydrodynamic (MHD) flow control, which uses the magnetic field to alter the trajectory of ions or electrons, can improve the aerodynamic characteristics of hypersonic vehicles effectively. As an intuitive aerodynamic phenomenon in the field of hypersonic MHD flow control, shock stand-off distance has attracted close attention from researchers. Under the influence of the applied magnetic field, the shock stand-off distance will change with it, of which the value can directly reflect the effect of the MHD flow control. However, the relevant theoretical models are still limited, and further development in this field is consequently needed. Focusing on dealing with this problem, MHD hypersonic shock stand-off distance of the spherical model is theoretically studied in this paper. By means of radially integrating the continuity equation and applying mathematical method of variable separation to the momentum equation, the analytical expression of MHD shock stand-off distance is obtained. The theoretical analysis was performed under the assumption of low magnetic Reynolds number, and the common-used dipole distribution of magnetic field as applied. The results show that the MHD stand-off distance of shock increases with the increase of magnetic interaction parameter. Moreover, the regularity can be found that as the speed of inflow becomes higher, magnetic interaction parameter can be viewed as the primary impact factor of shock stand-off distance under hypersonic condition. The theoretical model in this work can rapidly evaluate the effect of MHD control, and it can provide theoretical guidance to the design of experiment scheme and the analysis of results.

Aircraft Detection above Clouds by Sentinel-2 MSI Parallax

Detection of aircrafts in satellite images is a challenging problem when the background is strongly reflective clouds with varying transparency. We develop a fast and effective detection algorithm that can find almost all aircrafts above and between clouds in Sentinel-2 multispectral images. It exploits the time delay of a few seconds between the recorded multispectral images such that a moving aircraft is observed at different positions due to parallax effects. The aircraft speed, heading and altitude are also calculated accurately. Analysing images over the English Channel during fall 2020, we obtain a detection accuracy of 80%, where the most of the remaining were covered by clouds. We also analyse images in the 1.38 μm water absorption band, where only 61% of the aircrafts are detected.

RESEARCH PROGRESS ON MAGNETOHYDRODYNAMIC FLOW CONTROL UNDER TEST CONDITIONS WITH HIGH TEMPERATURE REAL GAS EFFECT

High speed and shock compression behind the bow shock of an aircraft head result in very high temperature, which would subsequently lead to a conductivity plasma flowfield around the vehicle. The plasma gas provides a direct working environment for the application of magnetic field. The magnetohydrodynamic (MHD) flow control, which uses the magnetic field to alter the trajectory of ions or electrons, can improve the aerodynamic characteristics of hypersonic vehicles effectively. It has potential prospects on aerodynamic force control and aerodynamic heating management. Besides, the development of superconducting materials and electromagnetic technology contribute to a great upsurge of MHD flow control research significantly. Although research work has been carried out in the field of MHD flow control at home and abroad, its experimental investigation is still challenging. And for the measurement of pressure and heat flux, there is no systematic conclusion because of the limited test conditions and measurement techniques. The results of different researchers may be different from each other and from the theoretical results and numerical simulations. Thus, the influence on the shock stand-off distance, pressure and heat flux under MHD flow control deserves an in-depth investigation. Besides, the numerical simulations and theoretical methods do also need reliable experimental data for variation. The aim of this review paper is to summarize and discuss the developments on MHD flow control technology based on high temperature real gas effect, including the experimental technique, numerical method, and the influence rules and dynamics mechanism of MHD flow control. Its development trend is also discussed and prospected in the paper.

The Flow Field, Particle Distribution, and Determination of the Optimal Sampling Area around Aircraft

AbstractParticle trajectories around an aircraft will change during a flight; therefore, analyzing particle distribution around the aircraft is necessary to accurately sample aerosols. Both computational fluid dynamics (CFD) simulations and wind tunnel experiments are employed to optimize the sampling zones around an aircraft. The wind tunnel model is the Harbin Y-12, similar to the Twin Otter and King Air. The aircraft head is taken as the coordinate original point. The coordinate X is parallel to the wings, the coordinate Y is parallel to the fuselage, and the coordinate Z is perpendicular to the fuselage. The results show that the closer the distance to the central line for the X direction is, the greater the velocity error is. A suitable position for sampling is under the fuselage because of low turbulence, convenient connection pipelines, and safety considerations. The shadow and enhancement zone area thicknesses gradually increase with increasing particle size. The shadow zone thickness under the fuselage is approximately 20, 70, 110, and 350 mm for particle sizes of 1, 10, 20, and 50 μm, respectively. The greater the distance from the aircraft head for the Y direction is, the smaller the velocity error is. The attack angle has no obvious effect on the flow speed at different positions. The CFD simulation results are in basic agreement with the wind tunnel experiment results. The optimal sampling zone is approximately 2300–6500 mm for the Y direction for the aircraft head, 250–500 mm for the X direction for the aircraft head, and 490–600 mm for the Z direction under the fuselage of aircraft.

Variational bias correction for Mode-S aircraft derived winds

A variational bias correction (VarBC) technique is proposed within the three-dimensional variational (3D-Var) assimilation system of the Météo-France convective scale model AROME to remove biases present in horizontal wind components derived from aircraft Mode-S data. A set of two predictors derived from the geometry between ground and air speeds has been chosen in order to correct the aircraft speed and heading. Data collected from a set of 8 ADS-B antennas located over France for two periods in 2018 (April and October) have been used to assess the VarBC. Thanks to the availability of anchoring data (radiosoundings, AMDAR aircraft reports), the adaptive bias correction scheme is very efficient for improving the quality of Mode-S derived winds to a level that is similar to those from AMDAR and Mode-S bias corrected by the KNMI. The heading bias correction is the most important one in order to reach background departure values around 2.5 m/s. The behaviour of the VarBC is assessed more precisely for specific aircraft where its capacity to adapt to rapid changes due for example to aircraft maintenance is demonstrated. Moreover, when examining separately predictors for both wind components they appear to converge most of the time towards similar speed and heading corrections. Additional quality controls have allowed to reach background departure values of 2.2 m/s while increasing by a factor of ten the number of aircraft observations to be assimilated in the AROME-France domain.

Gray System-Based Identification and Pre-Culling of Outliers Applied to Magnetic Sensor in Aeromagnetic Compensation

In aeromagnetic surveys, poor aircraft heading and weather may frequently cause a classical optically-pumped sensor to enter into or close to its dead zone, which results in unavoidable outliers that seriously reduce aeromagnetic compensation. To address these problems, a method to identify rapidly and pre-cull magnetic outliers based on the gray system theory is proposed to reduce their negative influence during the estimation of coefficients and target detection robustness. By constructing a gray region of aeromagnetic data and then checking whether the data at the end points of the region are normal, aeromagnetic outliers can be culled. The simulation results show that even if the outlier rate is increased to 20%, the average of the correct culling rate of the proposed method can still reach 99.67%, at which the culling effect is highly robust. We constructed an experimental survey platform and conducted a flight test. The results show that the improvement ratio of the proposed method can reach 4.36, which is 10.38 times higher than the conventional method.

Research on Control Technology of Jet and Rectifying Cone Combined Flow Field

As an active flow field control technology, reverse jet and rectifier cone can significantly affect the flow field around the high-speed aircraft and reduce the drag and heat of high-speed aircraft to a certain extent. In this paper, the CFD numerical method is used to simulate and analyze the flow around the bluff body front rectifier cone and the reverse jet interference flow field. Further considering the combination of the two, the flow field structure around the bluff body under the combination of rectifying cone and reverse jet flow was simulated. Research shows, for the flow field of a single reverse jet, the pressure ratio of the reverse jet to the main flow has a significant effect on the drag reduction performance. With the change of the pressure ratio of the jet to the main flow, two modes of long jet and short jet will appear. The structure of the short jet modal flow field is relatively stable. However, with the increase of attack angle, the shear layer of free flow will attach to the shock wave and form hot spot, which is a great threat to high-speed aircraft. When the rectifier cone and the reverse jet are combined, within a certain angle of attack, the wall will not form a reattachment shock wave. The area behind the bow shock and in front of the aircraft head is a free-state zone, which has a good cooling effect on the aircraft head. At the same time, the static pressure on the wall is reduced, which has a very good drag reduction effect.

Design of experiments: X-59 sonic thump carpets in the eastern United States

NASA is conducting a series of computational experiments to quantify atmospheric effects on low noise sonic booms. In the current study, simulated cruise nearfield pressure data from NASA’s X-59 Quiet Supersonic Technology aircraft were propagated from the aircraft to the ground at four cardinal headings through five years of realistic atmospheric profiles at 30 locations across the eastern USA. Statistical design of experiments was used to select the locations where primary sonic thump carpet widths (CW) and metric levels at the ground were computed. Atmospheric profiles were taken from the Climate Forecast System Reanalysis database, which contains reanalyzed atmospheric profiles four times daily. Decision tree analyses were performed to determine relative importance of predictors for CW and metric levels. Predictors included were latitude, longitude, date, time of day, season, climate, aircraft heading, and ground elevation. Results of this study indicate the propagation resolution needed to adequately characterize the distributions of CW and ground metric data in terms of the necessary separation distance between propagation locations and the total number of atmospheres through which to propagate. This resolution will be used for a follow-on study of simulated X-59 carpets across the entire US mainland.

Aircraft and Ship Velocity Determination in Sentinel-2 Multispectral Images.

The Sentinel-2 satellites in the Copernicus program provide high resolution multispectral images, which are recorded with temporal offsets up to 2.6 s. Moving aircrafts and ships are therefore observed at different positions due to the multispectral band offsets, from which velocities can be determined. We describe an algorithm for detecting aircrafts and ships, and determining their speed, heading, position, length, etc. Aircraft velocities are also affected by the parallax effect and jet streams, and we show how the altitude and the jet stream speed can be determined from the geometry of the aircraft and/or contrail heading. Ship speeds are more difficult to determine as wakes affect the average ship positions differently in the various multispectral bands, and more advanced corrections methods are shown to improve the velocity determination.

SOFIA Flight Planning and Execution

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is NASA’s airborne observatory. Observing with SOFIA has different challenges than observing from a ground based, or even space-based observatory. Although pointing SOFIA is similar to pointing an alt/az telescope, positioning the telescope requires not only the telescope assembly but also the aircraft. SOFIA’s telescope assembly can move in altitude nominally between 20∘ and 60∘. Since the telescope is pointed out the left side of a modified Boeing 747, the azimuth is determined by the aircraft heading. As a result, observing plans become the basis for a flight plan, and the science observation and aircraft operations are intrinsically linked. This paper will discuss flight planning and execution on this unique observatory.

The Flow Visualization CFD Studies of the Fuselage and Rolled-up Vortex Effects of the Chengdu J-10-like Fighter Canard

Fighter aircrafts with high maneuverability and swiftness are due to fuselage effects, caused by canard-fuselage-main wing configuration. Even though the flows around fighters are highly complex, mostly they create rolled-up vortices capable to delay stalls and increase maximum lifts (Calderon, Wang & Gursul, 2012; Mitchell & Delery, 2001; Boelens, 2012; Chen, Liu, Guo & Qu, 2015). The vortex dynamics analysis method employment is introduced, in this case we focus only on the fighter canard. It characterizes the vortex core, develops the pitching moment & main wing total lift, and exploits the vortex centre visualization, the strength, negative surface pressure and its trajectory.This paper explains the influence of the fighter fuselage, it generates rolled-up vortex effects, causes the flow deflected by the fighter fuselage head, strengthen the vortex centre to become vortex core. Above the aircraft head, due to the curved contour head effect, the second vortex centers are developed makes the vortex center above the head more dynamic. Comparing with fighter without fuselage, the flow property changes, for Chengdu J-10-like model with fuselage, are concentrated at the canard leading edge, where the negative pressures are stronger, since the maximum axial velocities of the vortex centre are higher, and give more distinctive vortex breakdown locations.

In-flight stability of quantum cascade laser-based infrared absorption spectroscopy measurements of atmospheric carbon monoxide

Airborne carbon monoxide (CO) measurements based on Quantum cascade Laser infrared Absorption Spectroscopy (QLAS) were performed on the German High-Altitude Long-range Observatory (HALO) aircraft during test flights in January 2015. Here we investigate the in-flight stability of TRISTAR (TRacer In-Situ Tdlas for Atmospheric Research), a multilaser QLAS instrument for the detection of tropospheric CO, methane and formaldehyde (HCHO). During one test flight the instrument was probed with tank air to measure a constant mixing ratio of CO and zero air for HCHO. Here we investigate the instrument stability for the CO channel of TRISTAR and identify potential noise sources as well as environmental processes that limit the stability of the instrument. The 1σ reproducibility of the constant CO measurement yields a value of 1.2% (2.9 ppbv) corresponding to an optical density limit of 0.001 for a 5-s average. The CO precision is ultimately limited by an etalon fringe originating from the double corner-cube White cell, whose phase and amplitude changes with the aircraft heading.