Lightweight is a substantial theme in the research and development of aerospace and aeronautical equipment due to its decisive impact on the comprehensive performance and operational efficiency of the equipment. Over the past decades， a handful of innovative optimization design approaches， emerging high-performance materials， and revolutionary manufacturing technologies have been uninterruptedly developed， and the level of lightweighting in aerospace and aeronautical equipment has been significantly advanced. However， the increasing demands for comprehensive performance and multifunctionality of the next generation of equipment present serious challenges to existing lightweight design and manufacturing technologies. Therefore， with a particular emphasis on the layout design， electromechanical system design， materials and structures， high-performance manufacturing and assembly， this paper analyzes the posed challenges and future perspectives.

UAV aerial images have more complex backgrounds and a large number of dense small targets compared with natural scene images, which impose higher requirements on the detection network. On the premise of ensuring real-time object detection, a YOLOv5-based UAV real-time dense small object detection algorithm is proposed for the problem of low accuracy of dense small object detection in UAV view. First, combining Spatial Attention Module (SAM) with Channel Attention Module (CAM), the fully connected layer after feature compression in CAM is improved to reduce the computational effort. In addition, the connection structure of CAM and SAM is changed to improve the spatial dimensional feature capture capability. In summary, a Spatial-Channel Attention Module (SCAM) is proposed to improve the model's attention to the aggregated regions of small targets in the feature map; secondly, an SCAM- based Attentional Feature Fusion module (SC-AFF) is proposed to enhance the feature fusion efficiency of small targets by adaptively assigning attentional weights according to feature maps of different scales; finally, a backbone network is introduced in the Transformer in the backbone network, and use the SC-AFF to improve the feature fusion at the original residual connections to better capture global information and rich contextual information, and improve the feature extraction capability of dense small targets in complex backgrounds. Experiments are conducted on the VisDrone2021 dataset. The effects of different network scale parameters and different input resolutions on the detection accuracy and speed of YOLOv5 are first investigated. The analysis concludes that YOLOv5s is more suitable to be used as a benchmark model for UAV real-time object detection. Under the benchmark of YOLOv5s, the improved model improves mAP50 by 6.4% and mAP75 by 5.8%, and the FPS for high-resolution images can reach 46. The mAP50 of the model trained at an input resolution of 1504×1504 can reach 54.5%, which is 11.5% better than that of YOLOv4. The accuracy is improved while the detection speed FPS remains at 46, which is more suitable for real-time UAV object detection in dense small target scenarios.

TDOA/FDOA localization is an important wireless positioning mechanism for moving emitters， and its location accuracy is greatly affected by measurement errors of TDOA/FDOA and prior measurement errors of sensor models （including sensor position and velocity）. To improve the localization performance under the condition of high-level measurement errors， a TDOA/FDOA cooperative localization method for multiple disjoint sources is proposed based on weighted multidimensional scaling analysis in this paper. The proposed method consists of two calculation stages： Stage-a and Stage-b. Specifically， in Stage-a， two groups of scalar product matrices in multidimensional scaling analysis are employed to form the positioning relationship， which is further used to yield the solutions for the locations of multiple disjoint sources and sensors by constructing a weighting matrix. In Stage-b， a constrained minimization model is established based on the intermediate variables introduced in multidimensional scaling analysis to determine the estimation errors in Stage-a. By solving this optimization problem， the expression for the localization errors in Stage-a are obtained， so as to refine the position and velocity estimates of the multiple disjoint sources as well as the sensors. In addition， the first-order error analysis is employed to prove that the proposed method can asymptotically reach the Cramér-Rao Bound （CRB） accuracy. Simulation results show that the new method outperforms the existing TDOA/FDOA positioning methods.

The future battlefield is confronted with the problems such as high complexity of the environment， strong antagonism of the game， high real-time response， information incompleteness， and boundary uncertainty. To win the future aerospace battlefield， the manned/unmanned aerial vehicle cooperative combat system can become the core key due to its advantages of dual effectiveness， complementarities of combat weaknesses， and high efficiency of action coordination. This paper focuses on the research status of Manned/Unmanned Aerial Vehicle （MAV/UAV） cooperative combat， which is a new direction of high difficulty， rapid development， broad prospects in applications and multidisciplinary combat. The research status of manned/unmanned cooperative combat is summarized from three aspects： system concepts， key technologies and challenges. The definitions of system combat， winning mechanism and application process and the key technologies such as detection and situational awareness， mission planning， command and decision making， formation control， and effectiveness evaluation are expounded. Finally， the challenges of MAV/UAV cooperative combat in the future battlefield are prospected， and new ideas for the development of intelligent combat technology in the future are provided.

The superconducting machine has prospects of a wide range of applications in aviation electric propulsion due to its advantages such as small size， high power density， and high efficiency. The characteristics and current situation of the superconducting pure/hybrid electric drive systems are compared， showing the importance of the superconducting machine for high power aviation electric propulsion. In view of different requirements for motors and generators for the superconducting electric drive system for high power aviation electric propulsion， the operating principles and structural topologies of those prototypes of High Temperature Superconducting （HTS） machines studied in the past are reviewed and classified， and the advantages and disadvantages are summarized and analyzed. On this basis， the key technologies of superconducting machine are outlined in terms of superconducting technology， AC superconducting armature， rotor technology， cryogenic technology and insulation technology. Under the background of aviation electrification， the progress in the application of superconducting electric drive system in aviation electric propulsion is outlined， and future development of superconducting electric aviation is also discussed.

Technological breakthroughs have once again spawned a lot of attention to the commercialization of Urban Air Mobility （UAM） in urban low-altitude airspace. The urban low-altitude airspace environment is complex， the density of urban air traffic flow in commercial scenarios is high， and the specifications of vehicles are not uniform. As a new infrastructure for UAM， low-altitude public routes are an important means for UAM to carry out refined management. However， the planning methods of low-altitude public routes， the required infrastructure， and the urban air traffic operation and control mode are still unclear. In response to the above issues， this article sorts out the basic concepts and development history of UAM and low-altitude public air routes， as well as UAM management based on low-altitude public air routes； In addition， an UAM operation management framework is proposed. Suggestions and countermeasures are provided on the possible responsibilities of relevant administrative departments in the development UAM； Finally， the construction method of low-altitude public routes network， the difficulties in the development process of UAM and implementation suggestions are summarized， in order to shed light on the healthy and orderly development of the UAM.

Next-generation Supersonic Transport Aircraft （STA） has become one of the main future directions for civil aviation transport. Compared with subsonic civil aircraft， STA involves a series of technical problems such as sonic boom and is confronted with more strict performance indexes， imposing higher requirements for the conceptual aerodynamic configuration design. This paper classifies the existing supersonic civil aircraft configurations in the world into three generations according to the design strategy and the main technical features. The first-generation configurations mainly adopt a delta wing/ double-delta wing platform to achieve supersonic civil flight and balance both high and low speed performance. The second-generation configurations take the low-boom and low-drag performance into consideration and employ the highly-swept arrow-wing tailless layout， while the third-generation focuses more on the multi-disciplinary comprehensive performance and the technical feasibility. Almost all these configurations adopt the T-tail or V-tail layout and the engine nacelle knapsack or tail crane layout. The technical bottlenecks and difficulties of the new generation STA conceptual-aerodynamic configuration design are then presented. The progress and state of the art of the conceptual design technology， low-boom design technology， supersonic drag reduction technology， and airframe-propulsion integrated design technology are reviewed. Finally， the development trend of a new-generation STA configuration is discussed， stressing some of the key scientific and technical issues to be broken through. Supersonic business jets or small and medium class STA will be the priority in the near future， with technical features approximating those of the third-generation configurations. Comprehensive performance and engineering realizability of factors such as sonic boom， drag reduction， airframe-propulsion integration， aeroelasticity， and man-machine efficacy should be the mainly concern in future research.

The development of reusable launch vehicles is the persistent pursuit of aerospace industry. Although the first flight of the fully reusable SpaceX two-stage heavy-lift starship was successfully launched， the starship was ultimately self-destructed due to the loss of control in the subsequent flight. After reviewing evolutionary design and the first flight experience of the heavy-lift starship， this paper analyzed the application modes of the heavy-lift starship based on the overall scheme， identified the key technologies involved， and summarized its impact on aerospace industry. Finally， the enlightenment and suggestions of the heavy-lift starship’s achievements to China’s aerospace industry are provided.

With the increasing convenience of data acquisition for aerial photography of Unmanned Aerial Vehicle （UAV）， the multi-target detection and tracking technology based on the UAV platform has developed rapidly and has broad prospects for applications in civil and military fields. In recent years， the rapid progress of in-depth learning has also provided a variety of more effective solutions. However， the challenging problems such as sudden changes in the appearance of the target， serious occlusion of the target area， and disappearance and reappearance of the target from the perspective of UAV have not been completely solved. In this paper， we summarize the algorithms for multi-target detection and tracking in UAV aerial video based on deep learning， and summarize the latest progress in this field， including multi-target detection and multi-object tracking. The multi-object detection module is divided into two parts： two-stage and one-stage detection. For the multi-object tracking module， according to the two classical frameworks of tracking-based detection and joint-detection tracking， the principles of the two algorithms are described and their advantages and disadvantages are analyzed. Then， the existing public data sets are statistically analyzed， and the optimal schemes of the benchmark challenge VisDrone Challenge in the field of multi-target detection and tracking based on UAV aerial video in recent years are compared and analyzed. Finally， the paper discusses the urgent problems of multi-object detection and tracking from the perspective of UAV and the possible research directions in the future， providing a reference for the follow-up researchers.

Morphing aircraft， capable of real-time shape deformation according to task requirements and flight conditions to achieve optimal flight performance， has emerged as a significant direction for the future development of aircraft. This paper reviews the research status of deformation modes and key technologies of aerodynamic layout design for morphing aircraft. Firstly， the development of morphing aircraft can be divided into two stages by the progression of time： the mechanical deformation stage and the flexible and muti-dimensional deformation stage. Then， this article summarizes morphing solutions for different parts of the aircraft， namely， the head deformation， wing deformation， power plant deformation， and combined deformation. It particularly explores the developmental history of various wing morphing schemes， discusses their applications in different aerodynamic configurations including variable sweep wing， variable forward sweep wing， folding wing， telescopic wing， oblique wing， continuous variable curvature wing， and analyzes their aerodynamic and stability characteristics， respectively. Next， the implementation objectives of morphing aircraft are summarized and divided into three types： single domain optimal variable configuration， multi-domain fusion variable configuration， and one vessel multi-energy variable configuration. Subsequently， compared with fixed shape aircraft， the key technical challenges in aerodynamic layout and overall coordination design， time-varying aerodynamic effect evaluation， aerodynamic layout scheme optimization， and multidisciplinary coupling design derived from the implementation of morphing aircraft are analyzed， with particular focus on the research progress and current status of dynamic aerodynamic calculation methods and aerodynamic optimization design technologies for morphing aircraft. Finally， the future research direction and development prospects of morphing technologies are envisioned. Targeting at the needs of wide velocity domain and large airspace flight， exploring new conceptual deformation methods that can improve the performance of multiple flight missions and establishing intelligent morphing design model and multidisciplinary strong coupling integrated design system will become important development trends.

SensorCraft is an early warning and surveillance and information synthesis aircraft proposed by the Air Force Research Laboratory， with high ceiling and long endurance. It adopts the platform-payload integration technology， with the dual features of the aircraft and sensor. Coupling of multiple elements between platform and payload means that the overall layout design is different from that of the traditional Intelligence， Surveillance and Reconnaissance （ISR） vehicle. Flight conditions and performance indexes bring new challenges to the aerodynamic design. Aeroelastic problem of large aspect ratio flexible wing not only worsens flight performance， but also leads to loss of electromagnetic performance of wing conformal antenna. This paper summarizes the technical characteristics of SensorCraft， expounds the development history of the United States SensorCraft system from two aspects of the flight platform and conformal antenna. From the perspective of technical characteristics， key technologies supporting SensorCraft are sorted out， such as integrated layout design， laminar drag reduction， gust alleviation， conformal antenna design， deformation measurement & reconstruction， and electromagnetic performance compensation. Relevant applications are introduced. The development trend of this aircraft is also discussed in terms of the flight ability， stealth ability， perception ability and coordination ability of the aircraft， so as to provide reference for the new ISR aircraft.

As application scenarios become more complex， the need for autonomous motion planning techniques which aims at generating collision-free path （trajectory） becomes more urgent. Although a large number of planning algorithms adapted to different scenarios have been proposed already， how to properly classify the existing results and analyze the advantages and disadvantages of different methods is still a problem that needs in-depth consideration. In this paper， the basic connotation of motion planning and the key steps of classical algorithms are explained. Secondly， aiming at the contradiction between real-time performance and the quality of solution path （trajectory）， the existing algorithm acceleration strategies are analyzed and summarized hierarchically based on whether differential constraint is considered. Finally， facing the new requirements of planning under uncertainty （i.e.， sensor uncertainty， future state uncertainty and environmental uncertainty） and intelligent planning， the latest achievements and development direction in the field of motion planning are reviewed. It is expected that the review can provide ideas for future research.

Aeroengine amalgamates state-of-the-art technologies across diverse domains， serving as a comprehensive manifestation of a nation’s prowess in science and industry. Frequent malfunctions occur due to its complicated structure and harsh service environment. Therefore， it is essential to employ prognostic and health management technology to provide crucial support for aviation safety and reliable operations. As vibration faults constitute a primary failure mode in aeroengine， this paper， grounded in this premise， systematically reviews and analyzes existing vibration monitoring and fault diagnosis for aviation engines both domestically and internationally. The analysis is categorized into three dimensions， covering the application of overall vibration monitoring and diagnostic systems， typical fault characteristics and diagnostic methods， and the overall vibration fault diagnostic technology， including dynamic analysis， signal processing techniques， and relevant technologies such as deep learning. Then， the problems and challenges faced by the existing vibration fault diagnosis of aeroengine are identified. Furthermore， future development goals are provided.

Being a novel and potential spacecraft autonomous navigation technology， X-ray pulsar-based navigation technology has irreplaceable advantages in deep space exploration， time reference autonomous maintenance. Firstly， this paper briefly introduces the background and significance of X-ray pulsar-based navigation. Secondly， the research progress of two key technologies of X-ray pulsar-based navigation， pulsar signal processing technology and pulsar navigation theory， is introduced. Thirdly， the research progress of applications of X-ray pulsar-based navigation is summarized. Finally， the development trend of X-ray pulsar navigation technology is presented and the future development are prospected.

Low-Altitude Intelligent Network （LAIN）， as a new type of intelligent network， relies on space-air-ground-sea facilities to constitute a digital intelligent network system. It is a key component of the space-air-ground integrated network， and can support the seamless and ubiquitous connections of the sixth generation communication technology and promote the development of intelligent network service from ground to low-altitude space. However， LAIN is still in the developing stage and faces the following key challenges： intractability of aerial control， severe spectrum interference， and multi-dimensional resource limitation. This article focuses on the issues of LAIN architecture and safety control， including the current development status of low-altitude network and its significance for industrial technology transformation. Then， from the perspective of spectrum resources， network resources， and airspace resource management， the recent related works are analyzed. Furthermore， we analyze the key technologies such as low-altitude aircraft air-ground spectrum sharing， sensing， transmission， computing networking coverage， low-altitude airspace intelligent supervision， and point out future development directions. Finally， an application demonstration of LAIN is proposed， aiming to satisfy the significant requirements for efficient operation and safety in low-altitude airspace， and providing the theoretical basis as well as technology for the further development of the next generation space-air-ground integrated network.

Multi-scale structure is one of the important directions of next-generation structural lightweighting and has great potential and strategic value for application in the aerospace field. Topology optimization techniques for multi-scale structures have also been extensively researched， leading to great progress and achievements. However， many challenges and difficulties remain before realizing actual engineering practice. This paper firstly introduces the mainstream methods and characteristics of single-scale structural topology optimization， the basic idea and special position of homogenization methods， as well as the relationship between topology optimization methods for multi-scale structures and topology optimization methods for single-scale structures. Then， using the structural distribution characteristics as the classification criteria， this paper systematically sorted out the topology optimization design methods for three distribution forms of multi-scale structures： periodic， functional gradient and heterogeneous. For the important issues， including structural connectivity， applicability of multi-scale methods， and application of machine learning technology in multi-scale structural topology optimization， relevant research progresses are reviewed and discussed. Finally， pressing challenges and important research directions in the field are summarized and prospected.

With the development of liquid rocket engine technologies， structural dynamic problems become one of the key factors affecting the life and reliability of engines. In the past decades， the design concepts and methods of the engine gradually developed from the initial static strength and safety life design to the combination of dynamic and static strength， and economic life design， which were widely used in engines， significantly improving the working reliability of the engine structures. However， the increasing size and complex structure and the extreme harshness of the working environment for the new rocket engines require urgent solution to the technical problems of engine structural dynamic design to meet the needs of high performance， high reliability， light weight and reusability. This paper reviews the key technologies such as load prediction， dynamic modeling and model updating， dynamic strength assessment and life prediction， and anti-fatigue design on account of dynamics optimization， based on the analysis of typical dynamic problems in engine structures. The research summary and prospect are also presented. This review will provide guidance for the development of structural dynamic design technology of liquid rocket engines.

The rapid development of brain and neuroscience in recent decades has initially revealed the neural mechanism of animal navigation. Drawing on the brain neural structures and information processing mechanisms， the study of brain-inspired intelligent navigation systems provides new inspiration for low-power， highly robust autonomous intelligent navigation in complex environments. Based on a detailed review of the neural mechanisms of animal spatial navigation， this paper then outlines and discusses current intelligent algorithms for robotic bionic brain-inspired navigation， which can be categorized into three types according to the three types of neural networks used to process navigation information for intelligent navigation： attractor neural networks， deep reinforcement learning， and spiking neural networks. Then， the ways for implementing brain-inspired navigation， including bionic intelligent sensors and neuromorphic processor platforms， are sorted out. Finally， the development trend of brain-inspired navigation is discussed， including further exploration of the brain neural mechanism of navigation in the biological world and its information processing process with low energy consumption and high robustness mechanism， subcategorization of the conceptual connotation of brain-inspired navigation， and the ways to improve the evaluation index and the unified implementation framework.

The development of electric Vertical Take-off and Landing （eVTOL） aircraft is greatly promoted for the advances in battery and motor technologies and the application of distributed electric propulsion system. In this paper， the advantages and disadvantages of different eVTOL configurations and their application scenarios are summarized， and a comprehensive comparison between eVTOL and conventional fuel aircraft is made in terms of performance， noise and cost. The interaction noise by rotors and rotor-wing is more prominent for eVTOL， but the electric propulsion rotor system with low tip speed and large rotor solidity greatly reduces its noise level （about a reduction of 15 dB）. Lithium-ion batteries are the main energy source for current and future eVTOL. The advanced battery material system， integrated design of battery-structure and excellent battery management system are effective ways to improve the energy density and energy security of the whole aircraft in the future. The redundant manipulation of eVTOL increases the difficulty of flight control system design， but improves the safety of the whole aircraft at the same time. Fault reconstruction and collaborative control are new challenges faced by eVTOL. A wide variety of configurations and novel design features such as high voltage power， electric propulsion， flight-by-wire flight system and electric actuation are proposed for eVTOLs. In the absence of flight test data， the system-based method is the main method for safety design of eVTOL.

In view of the demand for future aero-engines，combined with the characteristics and advantages of multi electric distributed control，the key technologies of fault diagnosis and accommodation of multi-electric distributed engine control system are studied based on advanced algorithms. Firstly，this paper summarizes the fault diagnosis and accommodation technology of multi-electric distributed engine control system at home and abroad from four aspects：distributed engine control system，more electric engine，fault diagnosis and fault-tolerant control methods and hardware in the loop simulation platform，and points out the key problems of fault diagnosis and accommodation of multi-electric distributed engine control system at present. Then the key technologies are proposed，which are the design of fault diagnosis and accommodation architecture of multi-electric distributed engine control system，the model-based fault diagnosis and fault-tolerant control method，the fault diagnosis and accommodation scheme of dual active redundant motor control system，the electro-mechanical actuator fault diagnosis and accommodation scheme based on deep learning，and the construction of hardware in the loop simulation platform. Finally，the future development trend of fault diagnosis and fault tolerance of aeroengine multi electric distributed control system is prospected.