Dynamic explosion point localization constitutes a pivotal element in damage assessment. The explosive sound wave, originating from the attenuation of a shock wave, is characterized by supersonic velocity and a defined sphere of influence. Accordingly, the accuracy of explosion point acoustic localization is susceptible to the influence of the explosive shock wave. To explore the impact of the explosive shock wave segment on the acoustic localization outcomes during the explosion point localization process, a wave arrival time-distance model for the attenuation of the shock wave into a sound wave was constructed, predicated on the pressure attenuation law of the explosive shock wave. This model was subsequently integrated into the localization methodology based on the time difference of arrival (TDOA). Utilizing a prototypical arrangement as a case study, the preset explosion point and the acoustic sensor array's position were delineated, and the corresponding wave arrival times were computed. The TDOA-based localization approach was employed to retrodict the position of the explosion point relative to the acoustic sensor array, and the acoustic localization error of the explosion point was ascertained by juxtaposing the retrodicted position with the preset position. Furthermore, by modulating the preset explosion point position and the charge mass, the influence of the explosive shock wave on the acoustic localization error was scrutinized. The research findings suggest that the charge mass and the distance from the explosion center are the predominant factors influencing the localization error. As the scaled distance escalates, the localization error induced by the shock wave exhibits a diminishing trend. When the scaled distance surpasses 18.45, the relative distance error can be mitigated to below 1%. It is anticipated that these findings will serve as a reference for the systematic error correction of explosion point acoustic localization, thereby enhancing the computational precision of explosion point acoustic localization.

With the progressive complication of modern war scenarios, traditional loitering munition which is only suitable for a unitary combat environment is failed to meet the needs of the actual warfare. The trans-medium loitering munition swarm can lead to revolutionary changes of modern military field due to its excellent multi- scenario adaptability. A comprehensive analysis is given from three aspects: the basic design of loitering munition, the unique performance of trans-medium aircraft, and the intelligent management of swarm technology. The core theory and technology of trans-medium loitering munition swarm are studied. Based on the new characteristics of equipment, command, and personnel in modern wars, the future development trend of trans-medium loitering munition swarm is prospected.

In this paper, a trajectory optimization method of hypersonic glide missile is put forward by using penalty function method to hand non full course flying height and angle of attack constraints, which is based on Gauss Pseudo-spectral Method and takes into account multi phases, multi complex constraints and penetration mission-oriented requirements and so on. Its simulation results show that all constraint indexes are effectively controlled, and the penalty function method has more advantages in handling mission segmented constraints compared to conventional segmented constraint methods, which verified the effective coverage ability of the method under different ranges, launch heights and target heights.

Aiming at the problems of uncontrollable drop point and insufficient strike accuracy of the traditional terminal sensitive projectile, this paper proposes a parafoil based terminal sensitive projectile drop point control technology, which adopts parafoil instead of traditional parachute to achieve accurate control of its drop point. Based on the proposed parafoil-missile system, this paper designs an accurate parafoil-missile yaw angle controller based on active disturbance rejection control technology, which can offset the interference caused by the external wind field and compensate for the initial position error of the non-sensitive missile, so as to achieve accurate autonomous control of the system. Based on the above research content, the parafoil- missile system is built in this paper, and the actual airdrop experiment is carried out. In the experiment of airdrop, the error of the final landing point of the parachute-projectile system is less than 30 meters, and the minimum error of the air level is less than 4 meters, which proves the effectiveness of the proposed algorithm and provides a new idea for the design of smart ammunition in China.

Artificial intelligence technology is widely used in the military field, which significantly improves combat efficiency and promotes the development of military technology. The US military is in a leading position in the research and application of artificial intelligence technology in the military field, which was discussed in detail. The application of artificial intelligence technology in intelligence, surveillance and reconnaissance, logistics support, cyber operations, command and control, semi-autonomous and autonomous vehicles and autonomous weapons and other fields are deeply analyzed, and the future development trend of artificial intelligence technology in the military field is predicted. Finally, it points out the guiding and referential role for the domestic military field to carry out artificial intelligence technology research.

The dynamic behavior of hemispherical resonator comprises the physical basis of hemispherical resonator gyros (HRG). This paper concerns the common problems that exists in the domestic researches of dynamic modeling of HRG to date, such as the lack of specific sources of reference, plenty of ambiguous deductions (some are even incorrect), hence the derivation process of dynamic modeling of resonator is carefully presented in detail. The paper summarizes the general background knowledge of relevant disciplines, and teases out two main types of modeling thoughts, in the sake of providing a theoretical support for the subsequent researches and engineering applications. Firstly, the elastic shell theory used as a general basis in dynamic modeling of hemispherical resonator is introduced, including the elastic geometric equations that describe the relationship between strain and displacement and the Hooke’s law that relates strain to stress; then the modeling method based on the d’Alembert principle commonly used in early theoretical researches is presented, and the second-order motion equations of resonator is obtained by establishing equilibrium equations and load analysis; finally, the modeling method based on Lagrangian mechanics which is inspired from aboard research is introduced, and the second-order motion equations are derived by calculating the kinetic and strain energy of the overall resonator with substitution of the Lagrangian equations. The latter method is increasingly popular by domestic researchers in recent years.

In order to investigate the blast resistance of a 316L stainless steel honeycomb sandwich structure, a honeycomb sandwich structure was designed and fabricated using 316L stainless steel powder by selective laser melting (SLM). Concurrently, solid panels of equivalent surface density were produced by this method and constituted the control group. The mechanical behavior of the structure under near-field static explosion load is obtained through static explosion experiments and LS-DYNA simulation experiments, and the propagation mode of the stress wave within it is investigated in order to elucidate the underlying anti-explosion principle. Moreover, optistruct is utilized to optimize the topology and structure of the structure, with the objective of enhancing its blast resistance. The findings indicate that the backplate deflection of the porous sandwich structure is diminished by 13.2% in comparison to that of the plate with isoplanar density, thereby enhancing blast resistance. The established numerical model of fluid-solid coupling is capable of describing the three phases of the static explosion experiment, namely the shock wave propagation phase, the fluid-solid coupling phase, and the inertia phase. The explosion experiment yielded definitive results at the center of the target plate, thereby demonstrating that the "川" crack is caused by residual core layer extrusion. Moreover, the core layer deformation failure mechanism for the honeycomb panel was observed to manifest as in-plane stretching and tearing. The optistruct optimization results demonstrate the formation of a triangular skeleton and circular holes, alternating with corrugated plates. The structure, optimized for a corrugated core target plate, displays enhanced resilience in comparison to the optimization of a traditional honeycomb sandwich panel. The explosion load backboard deflection exhibited a 25.4% reduction, the peak pressure behind the plate demonstrated a 17.6% reduction, and the blast resistance was significantly enhanced. In comparison to honeycomb panels, the circular hole structure has been demonstrated to reduce the backplane deflection by 38.1%, while the triangular hole structure has been shown to reduce the peak pressure behind the plate by 22.4%.

In order to improve the penetration ability of multiple explosive formed projectile (MEFP) to armored targets, based on the design of end face MEFP, a combined end face ring double layer MEFP charging structure was constructed, which could form one main EFP and 24 auxiliary EFP in the circumferential direction, and could achieve multi-point damage to armored targets. ANSYS/LS-DYNA software was used to study the influence of the structural parameters of the cartridge cover on the molding effect and penetration performance of the MEFP warhead. The results show that when the wall thickness of the auxiliary cover increases, the projectile velocity of the auxiliary cover gradually decreases, the projectile dispersion angle of the middle auxiliary cover gradually decreases, and the projectile dispersion angle of the outer auxiliary cover gradually increases. When the radius of curvature of the auxiliary hood increases, the projectile velocity of the auxiliary hood gradually decreases, the angle of departure of the intermediate auxiliary hood gradually increases, and the angle of departure of the outer auxiliary hood gradually decreases. When the span of the auxiliary hood increases, the projectile velocity of the auxiliary hood gradually increases, the angle of dispersion of the intermediate auxiliary hood projectile decreases, and the angle of dispersion of the peripheral auxiliary hood projectile increases. The MEFP can penetrate 15 mm thick 45# steel target, thus effectively increasing the number of damage elements and damage area. The annular double layer MEFP structure of the end face combined charge structure has important reference significance for the warhead design of the terminal sensitive bomb.

The active sidestick is a crucial control device that can adjust the flight attitude of an aircraft. In the automatic flight mode, the active sidestick follow-up function tracks the control commands from the flight controller in real-time to enhance the pilot's perception of the aircraft's flight status, thereby effectively improving flight safety. However, unknown disturbance torques in the system can degrade the tracking accuracy of the active sidestick. To address this challenge, a control method based on composite nonlinear feedback and adaptive integral sliding mode is proposed for the follow-up control of the active sidestick. This method integrates an integral sliding mode control algorithm and the composite nonlinear feedback control algorithm, where the composite nonlinear feedback control effectively improves the steady-state performance of the active sidestick system, and the adaptive integral sliding mode control effectively restrains unknown system disturbances. Extensive experimental results show that the proposed improved active sidestick follow-up control algorithm can reduce the adjustment time by approximately 41% and the steady-state error by about 93.6% compared to the previous composite nonlinear feedback control algorithm. Furthermore, under disturbance conditions, the improved follow-up control algorithm can reduce the adjustment time by about 79% compared to the traditional PID algorithm. This demonstrates that the designed improved active sidestick follow-up control algorithm can significantly enhance the system's control accuracy and response performance, and possess excellent disturbance rejection capabilities.

The quality of explosive charge is a key factor affecting the performance of artillery weapons, and the explosive charge is often a mixture of powders. To improve the quality of cylinders made by a mixture of metal and non-metal powders, the mechanical behavior of the cylinders was described using continuum plasticity theory, the Shima-Oyane model and the Ogden model were employed as the material constitutive models for the cylinders and the rubber sleeve, respectively. And a simulation model for the isostatic pressing of cylinders was developed utilizing the nonlinear finite element software MSC.Marc. Based on the simulation model, the forming mechanism of cylinders was explored, and a comparative study was conducted on the influence of isostatic pressing process parameters on the forming quality of the cylinders. The results indicated that the simulation model could effectively reflect the forming characteristics of the cylinders. The maximum pressure and it’s holding time of isostatic pressing were the key factors that influenced the quality of the cylinders. When the pressure was set at 240 MPa and the holding time exceeded 400 s, the overall relative density of the cylinders reached above 97%, with the density distribution difference was below 0.5%. The results of the isostatic pressing experiment verified the accuracy of the simulation analysis results. The cylinders with approximate length-to-diameter ratios of 5∶1 achieved a higher process standard and satisfied the process requirements.

This paper proposes a new kind of anti-interception communication system based on Multi-layer weighted-type fractional Fourier transform (WFRFT) and multiple input multiple output (MIMO). ML-WFRFT improves anti-interception performance of the signal and MIMO improves spectrum utilization. The recognition method based on higher-order cumulants (HOC) is improved, and the anti-interception performance of the communication system is quantitatively analyzed through the recognition probability. As the modulation order increases, the anti-intercept performance is continuously enhanced. When the two modulation orders are 0.7 and 0.8, respectively, the signal-to-noise ratio is in the range of [0,2], the correct recognition probability of QPSK signal is less than 0.06.

Orienting toward the demand for long-endurance and high-precision autonomous navigation technology, it is of extremely significant practical importance to systematically tease out and review the development history and current status of key technologies of optical gyro rotating modulation inertial navigation systems (INS). Firstly, in light of the error characteristics of inertial navigation systems, the fundamental principle of rotating modulation technology is elaborated. This principle plays a crucial role in enhancing the accuracy and reliability of navigation. Secondly, a comprehensive review and analysis of the development history of rotating inertial navigation systems in Western countries such as Europe and the United States is conducted. The technical logic behind the evolution of these systems is examined, providing valuable insights for future development. Additionally, the current status of the development of rotating inertial navigation systems in China is summarized. Finally, with the aim of improving the autonomous navigation accuracy of the system, the key technologies and research status of rotating inertial navigation systems that need to be addressed are analyzed from three aspects: rotation strategy optimization, error calibration, and initial alignment. This in-depth analysis helps identify the challenges and opportunities in this field. Based on the summary of the optical gyro rotating modulation inertial navigation system and the development of key technologies, several thoughts are put forward for the subsequent research on rotating inertial navigation systems, which can serve as a valuable reference for the research on high-precision autonomous navigation technology.

For loitering munition patrol flight trajectory path planning algorithm design and combat mission scenarios, combined with a space based on 2D and 3D digital terrain model, based on the nature of ants foraging path planning algorithm of the shortest path theory, implement cruise missile threat to the established operational area designated objectives cruise flight path planning of obstacle avoidance. The correctness and effectiveness of the ant colony algorithm are verified by the flight simulation and analysis of the patrolling missile in the established environment.

This article proposes a heading calculation and integrated navigation algorithm based on continuous matching, which realizes the use of small field of view guided cameras to calculate the heading and provides a low-cost heading measurement and integrated navigation solution for unmanned aerial vehicles. The algorithm first calculates the attitude increment based on the essential matrix obtained from continuous matching, and further calculates the heading angle of the current frame through the first frame attitude matrix and joint calibration matrix. Based on this, a fusion algorithm for MEMS navigation solution and visual continuous matching is designed based on inertial navigation attitude filtering. To verify the accuracy and computational efficiency of the algorithm proposed in this paper, an inertial/visual combination device and a captive flight experimental system are constructed. The flight experiment results show that for cameras with a pixel count of 1 920×1 080, the matching success rate reaches 99.6% during flight at an altitude of 80~200 m. The heading calculation accuracy is better than 0.21° and the update frequency is better than 20 Hz during half hour navigation. Compared with traditional methods, it has a higher matching success rate, heading calculation accuracy, and lower time consumption.

Target detection in remote sensing image (RSI) is an important and challenging research. Aiming at the problems of relatively small targets, uneven non-target, complex background and diverse deformation in RSI, a dilated spatial pyramid pooling U-Net (DSPPU) model is constructed for multi-target detection in RSI. In DPPU, dilated multi-scale convolution is used to extract the classification features of multi-scale targets, and dilated spatial pooling pyramid (DSPP) module is used to enlarge the convolutional receptive field to extract more adequate target features. Moreover, attention mechanism, residual connection and skip connection are used to fully retain the sensitive features of the RSI extracted by the convolutional layer. Experimental results on EORSSD, a public remote sensing image database show that the proposed method can detect multi-scale objects from complex and diverse RSI with a detection accuracy of 96.56%.

With the continuous progress of computer hardware and software technology, the task functions integrated in the airborne computing platform are increasing day by day, resulting in the scale and complexity of the internal computing needs of the platform. In the face of the rapid growth of intelligent applications, the traditional single processor architecture is no longer enough to cope with a variety of complex tasks. Therefore, based on the OpenVPX standard, this study defines and designs a 3U heterogeneous fusion processing module that conforms to the hardware open architecture to meet the needs of a variety of complex tasks. This research also proposes a heterogeneous computing resource pooling technology, which aims to achieve rapid deployment and efficient operation of multi-type task applications, while reducing communication latency, and significantly improving the processing power and applicability of computing platforms. Experimental verification shows that, compared with multi-CPU architecture, the processing time of the heterogeneous fusion processing module designed in this paper is about 4.8 times shorter when executing specific neural network algorithms, which proves that its performance is significantly improved. The results of this study not only demonstrate the significant performance advantages of heterogeneous fusion processing modules in airborne intelligent computing applications, but also provide innovative solutions and technical support for the future development of aviation computing platforms.

Accurately and quickly detecting military targets in complex scenarios has important military value in perceiving battlefield situations, conducting reconnaissance and early warning analysis, and providing precise missile guidance. A multi-scale object detection algorithm AEM-YOLOV5 (AFPN-EMA-MPDIoU-YOLOV5) based on improvements to YOLOV5s is proposed to address the issues of poor feature learning ability, low detection accuracy, and high computational complexity in existing algorithms. Firstly, the AFPN asymptotic feature pyramid network is introduced into the neck network to gradually fuse the detailed information at the bottom of the image and the high-level semantic features at the top, enhancing the network feature fusion effect. Secondly, an EMA attention mechanism module is added before each detection branch to aggregate pixel level features across spaces, improving the level of attention to multi-scale targets in complex scenes. Finally, MPDIoU is used to replace the original C_IoU bounding box loss function in YOLOV5, solving the problem of C_IoU degradation when the predicted box aspect ratio is the same but the absolute value is different, making the regression results more accurate. The experimental results show that the improved algorithm performs well on the RSOD dataset, P_mAP50 reaches 94.5%, FPS reaches 42 frame/s, and model size is 14.8 MB. Compared with existing algorithms, the improved algorithm significantly improves its performance, meets the real-time requirements of military target detection, and the model is lightweight.

In order to explore the after-effect debris cloud characteristics of explosionally-formed projectile (EFP) with dense head and small aspect ratio, the FEM-SPH algorithm was used in this study to analyze the debris cloud formation process of EFP simulated projectile with an aspect ratio of 1.2 in red copper and nickel alloys. The study found: the fragment cloud after penetration of a projectile with a small aspect ratio presents an elliptic structure composed of tiny projectiles and fragments of the target plate. The increase of projectile size and penetration speed leads to the formation of more and higher fragment clouds behind the target. The residual nickel alloy projectiles exist in the head of the fragment cloud in an upset shape, causing secondary penetration of the target, while the red copper fragments have a greater degree of fragmentation. To form a large area of damage to the aftereffect target, when the projectile density is constant, the strength of the target plate mainly affects the axial expansion ability of the debris cloud, and for different projectile target materials, the radial expansion ability of the debris cloud mainly depends on the density ratio ρ_b. The research conclusion is of great significance to the design of EFP warhead’s after-effect power.

Heterogeneous scene matching, as an important auxiliary navigation method, has been widely studied. However, due to the influence of nonlinear radiation distortion and geometric deformation between heterogeneous image pairs, achieving heterogeneous image matching remains a challenging task. To address these issues, a heterogeneous scene matching method with rotation and scale invariance is proposed to simultaneously estimate the rotation, scale, and displacement variations between heterogeneous image pairs. Firstly, based on the local structural relationships of the image, local self-similarity descriptors (LSS) are used for feature description to resist the influence of nonlinear radiation differences and local deformations. Combined with the logarithmic polar coordinate transformation, the overall rotation and scale changes of the image are orthogonally expanded and represented separately in the Cartesian coordinate system. Finally, by utilizing the continuity of displacement estimation, rotation, and scale estimation, a five-dimensional feature descriptor is constructed and using phase correlation method estimates the variation of image rotation, scale and displacement simultaneously. Experiments conducted on three common types of heterogeneous image matching tasks shows that the proposed method achieves a matching accuracy of at least 4.5% higher than existing state-of-the-art methods tech, that highlights its effectiveness in the field of heterogeneous scene matching.

Image matching plays a vital role in UAV visual navigation. There have been many excellent image matching algorithms in this field, but there are few reports on heterogeneous image matching in season-changing. In order to further expand the current research work in this field, an image matching algorithm based on fuzzy information granules is proposed to solve the problem of heterogeneous image matching in season-changing. Firstly, according to the ground resolution of the satellite image and the UAV aerial image, the scaling factor of the UAV aerial image is determined, and then the scale preprocessing of the UAV aerial image is carried out; Secondly, an image matching method is established based on fuzzy information granules, and similarity matching is performed on the extracted edges to obtain the matching position between the UAV aerial image and the satellite image; Finally, validation is performed on winter and summer UAV aerial imagery and satellite imagery datasets. Experimental results show that the algorithm has strong robustness, improves image matching accuracy, and provides a new idea for UAV visual localization.

In order to study the penetration power of ogive-nose projectile under the condition of wide velocity range, the ANSYS/LS-DYNA finite element analysis software is used to simulate the penetration of the ogive-nose projectile into concrete target plate without considering the impact response characteristics of its range. The effects of projectile material, caliber radius head, length-diameter ratio and mass on the penetration performance are studied under the impact velocity of 2.0Ma~6.0Ma. The results show that with the increase of the target velocity, the dimensionless penetration depth of the projectile increases first and then decreases. At the same time, compared with 93 tungsten alloy and TA7 titanium alloy, the penetration performance of G50 alloy steel is better. The caliber radius head has a significant effect on the dimensionless penetration depth during low-speed penetration, and the degree of influence is reduced during ultra-high-speed penetrating. The optimal caliber radius head ratio of the projectile is 3~4. The length-diameter ratio is positively correlated with the penetration depth at low speed penetration and negatively correlated with the penetration depth at ultra-high speed penetrating. The dimensionless penetration depth decreases with the increase of the length-diameter ratio, and the optimal length-diameter ratio of the projectile is 4~5. The mass has a significant effect on the depth of penetration, and has little effect on the dimensionless depth of penetration and the critical transformation rate. The critical transformation rate appears at 3.5Ma~4Ma.

Micro-accelerometers are widely utilized in fields such as inertial navigation due to their compact size and high measurement accuracy. MOEMS (micro-opto-electro-mechanical system) accelerometers, based on optical measurement principles, offer enhanced measurement accuracy and are less susceptible to electromagnetic interference, making them highly promising for future development. However, external environmental changes, particularly fluctuations in temperature, can adversely affect the performance of micro-accelerometers. High-precision micro-optical accelerometers are especially sensitive to temperature variations due to their optical cavity length, which can lead to a decrease in detection accuracy. Therefore, improving temperature stability is crucial. Temperature control is the most effective method to mitigate the thermal effects on micro-optical accelerometer chips. This paper proposes a closed-loop temperature control scheme based on genetic algorithms and fuzzy PID (proportional-integral-derivative) control for a sandwich-structured chip-level packaged MOEMS accelerometer. The work involves designing a temperature control circuit, with a microcontroller serving as the main control unit, determining the controlled object model, then identifying the transfer function as well as tunning and debugging the system's temperature control parameters. The sandwich-type micro-optical accelerometer packaging structure studied in this paper provides favorable conditions for temperature control. The temperature control scheme with PID control parameters optimizes based on fuzzy logic and genetic algorithms exhibits excellent control performance and shorter regulation time. Theoretically, it significantly reduces the temperature control error by several orders of magnitude, effectively minimizing the thermal effects on high-precision micro-optical accelerometer chips. This temperature control scheme also demonstrates strong robustness, making it practically applicable to other micro-sensors with small, semi-enclosed structures.

To investigate the damage effectiveness of low, slow and small Unmanned Aerial Vehicles(UAVs) under fragmentation strikes, an evaluation model is established to comprehensively assess the damage effectiveness of fragments against UAVs. Numerical simulations are conducted to analyze the damage probability of a single fragment impacting various UAV compartments under different initial velocities, diameters, and material conditions, followed by extensive shooting simulations using the Monte Carlo method, with thousands of iterations to ensure statistical robustness. The results indicate that the initial velocity, diameter, and material of the fragment significantly influence the damage probability. An increase in initial velocity and diameter notably enhances the damage probability; however, the effectiveness tends to saturate within the velocity range of 900~1 500 m/s and diameter range of 4~8 mm, showing diminishing returns beyond these thresholds. The use of multiple fragments significantly increases the damage probability, suggesting that an increase in the number of fragments leads to a substantial improvement in damage effectiveness, making the quantity of fragments a crucial factor in determining the overall damage outcomes. Based on these findings, selecting fragment diameters between 2 mm and 4 mm, initial velocities between 600 m/s and 900 m/s, and appropriate materials can optimize the design of fragmentation warheads, thereby significantly enhancing their damage effectiveness against UAVs. This study provides a scientific basis for the precise evaluation of UAV damage effectiveness, offering valuable insights for the development of more effective countermeasures and supporting informed decision-making in combat scenarios to ensure enhanced operational effectiveness and strategic advantages.

The dynamic load has a significant impact on the structural security and measurement accuracy of the hinge moment balance in wind tunnels on the vehicle. To solve the dynamic load problem, a monitoring and prewarning system for dynamic load in hinge moment wind tunnel test is developed. Designing scheme of the software and hardware, and dynamic data processing method and critical value setting method for the monitoring and prewarning system are introduced in detail, and the system is experimentally verified. The study results show that the monitoring and prewarning system can effectively provide an early warning of the dynamic load that exists in hinge moment wind tunnel test, and adjusting the inherent frequency of the control surface/balance system away from the aerodynamic excitation frequency of flow separation can ensure the safety of the test and reliability of the test data.

For the segmented combustion instability phenomenon of slender solid rocket motors in the ground test, it can obtained the distribution range of pressure oscillation frequency in the combustion chamber by mean of acoustic cavity frequency analysis, analyzing the main factors of two-stage combustion instability from a perspective of acoustic-vortex coupling and propellant combustion response. Then through comparison experiment, comparing the combustion instability of the motor with the same grain configuration and different propellant formulations and combiningewith the acoustic cavity mode of the combustion chamber at the initial, middle and end time and the flow field vortex structure computation of the combustion chamber and the pressure coupled response function test results of the T-burner, the conclusion is that the combustion instability phenomenon at the initial stage of the motor operation is due to the fact that the vortex shedding frequency caused by the grain configuration is close to the frequency of the acoustic field of the chamber to generate coupling gain and induce the pressure oscillation. At the end of the operation of the motor, the combustion instability frequency is different from the initial frequency range, and there are frequency multiplication characteristics, the instability is caused by the combustion response of the propellant. The analysis unfolds from the two-stage combustion instability in the ground test andprovids a reference to optimize solid rocket design and effective avoidance of such problems in engineering design.

Aerial remote sensing image aircraft detection (ARSIAD) is an important and challenging research. Aiming at the problems of existing ARSIAD methods, such as blurred edges of detection aircrafts, low detection accuracy of small aircrafts and insufficient use of global context information of aerial remote sensing image (ARSI), an ARSIAD method based on feature fusion of multi-scale U-Net and Transformer (MSU-Trans) is proposed. In MSU-Trans, multi-scale convolution module inception is used to extract the classification features of various aircrafts in ARSI, Transformer is used to enhance the global semantic detection performance of the model, and feature fusion module is used to integrate high-level and low-level features to obtain complete edge and texture features of aircraft images, and improve the overall detection performance of MSU-Trans. It integrates the strong local feature extraction capability of multi-scale U-Net and strong global context dependency extraction capability of Transformer to improve the overall detection performance of MSU-Trans. Experiments on an ARSI set show that MSU-Trans has higher detection accuracy than U-Net, multi-scale U-Net and attention U-Nets, with the accuracy over 95%. This method provides some technical support for ARSIAD.

The committed character of harmonic radar is that the receiving signal freckly is three times of transmitting signal. Then the band of antenna is very wide. A compact shared-aperture fuze antenna is designed using X-band as the transmitting frequency and Ka-band as the receiving harmonic frequency. A dual-band and frequency selective radome is designed and fabricated. The radome can be considered as a narrow-band filter. The transmitting and receiving antenna share the same radome. This radome is a kind of simple and effective measure which improves the capability of wide band blanket anti-jamming.

In order to provide GNSS positioning performance under the whole constellation for the global users, the performance of GPS, GLONASS, BDS and GALILEO multi-system constellation fusion needs to be studied. Spatial sampling is conducted according to the global latitude and longitude resolution of 5°×2.5° to evaluate the system with different cut-off angles and multi-constellation combination, including the number of visible satellites, PDOP value and PDOP availability. The results show that the PDOP availability for BDS stand-alone system under 10° cut-off angle is over 98.6%, that for dual-system under 30° cut-off angle is over 95%, and that for four-systems under 40° cut-off angle is up to 100%, dual-system and four-system fusion can significantly improve the satellite availability.

In order to strengthen the detection capability of small infrared targets under complex background, an improved WSLCM(weighted local contrast measure) detection algorithm is proposed. In the pre-processing stage of WSLCM, adaptive curvature filtering is used to process the image in multi-scale, and the real object is not submerged in the process of background suppression. In the background suppression calculation, the maximum gray value of the background block is selected as the background estimation to reduce the false alarm rate. At the same time, target enhancement factor and background suppression factor are introduced to enhance the robustness of the algorithm, eliminate the influence of background noise, and enhance the detection ability of infrared small targets. The algorithm IP verification is carried out by the embedded ZYNQ platform, and the algorithm can recognize and detect the small target in the specific scene by using the hardware and software cooperation. Experiments show that compared with the traditional WSLCM algorithm, BSF and SCRG indexes are significantly improved, the continuous frame detection rate is 93.2%, and the detection efficiency of embedded platform is 17.6% higher than that of PC, which verifies the effectiveness of the algorithm and embedded system.

Accurate detection and excitation of standing wave vector on hemispherical resonator are crucial for achieving rate-integrating hemispherical resonator gyro (RI-HRG). In this work, a dual-channel synchronous measurement and control scheme based on synchronous detection and excitation of orthometric azimuth vibration signals is proposed for RI-HRG and the effectiveness of this scheme has been verified with experiment. Firstly, the demodulation scheme for the standing wave on resonator is optimized. Secondly, a multi-loop control method suitable for the dual-channel synchronous measurement and control mode of RI-HRG is designed, achieving frequency tracking, amplitude and quadrature control of the standing wave,and an angular position prediction scheme is involved to ensure the synchronization of detection and driving. Then, to overcome the weak capabilities of FPGA floating-point computation and the difficulties in parameter debugging and algorithm optimization, a dual-digital-core control circuit based on “FPGA+DSP” is designed and implemented. The dual-digital-core control circuit greatly enhances computational accuracy and compilation efficiency while ensuring the timing characteristics of the synchronous measurement and control system. Finally, the proposed multi-loop control method for the RI-HRG is validated with experiments. The experimental results show that the rate-integrating control mode of the HRG is implemented effectively with dual-channel synchronous measurement and control system designed in this paper, and the performances of gyro, such as angular rate output noise and scale factor nonlinearity, has been improved. The gyro's angular rate output noise standard deviation reaches below 0.001°/s, and the scale factor nonlinearity reaches 1.298×10^-5.

To address the issue of hit accuracy of terminal guidance phase of a rotor loitering terminal sensitive projectile, that is jointly affected by detection system errors and attitude disturbances, this study focuses on the dynamic factors which affect the dispersion of EFP warhead destruction element. In the study, a dynamic impact point model is established based on the seeker system detection error, airframe's spatial attitude disturbances, implicated motion deviation of the warhead destruction element and system latency, meanwhile the trajectory of missile target rendezvous and swinging attitude correction in the final guidance phase are utilized. By taking full advantage of airframe's attitude information and with the help of experimental flight data, the model can be used to analyze the influence of each factor on the point of impact. Simulation and analysis results demonstrate that, under certain random disturbances, the primary factor causing aiming error is the airframe's attitude disturbances and rendezvous trajectory deviation, so that gain the attitude angle control requirements necessary to achieve a desired hit rate on a typical armored target. This study provides a theoretical basis for the research on guidance law and trajectory prediction control of loitering terminal sensitive projectile.

Aiming at the positioning error caused by the flight attitude in a visual scene matching navigation of guided munitions, an inertial aided visual scene matching navigation method is proposed for high dynamic and inclined viewing angles. This method improves the existing scene matching navigation method. It uses inertial attitude to assist visual scene matching navigation to solve the homography matrix and the resampling scale between the images before and after correction, and corrects the distortion of the real-time images, which can avoid the blind matching of multiple iterations in the subsequent matching algorithm and improve the algorithm efficiency. At the same time, the position information of the matching points obtained by the matching algorithm is corrected to reduce the positioning deviation during the flight. Experimental results show that this method can effectively reduce the navigation and positioning errors caused by flight attitude in high dynamic environment. The average error of the image correction algorithm is 1.07 pixels and the time consumption is 0.005 s, which reduces the average error by 69% and the time is shortened by 88% compared with the traditional method. The position error of the whole navigation system is 11.23 m (RMSE), and the update frequency is better than 10 Hz, which can effectively cope with the high dynamic and inclined environment of mid-terminal guidance. It provides a low-cost autonomous navigation solution for guided munitions under satellites denial conditions

The fiber optic gyroscope (FOG) serves as a high-precision angular velocity sensor and plays a critical role in inertial navigation, positioning and orientation, and attitude control systems. However, the thermally induced bias drift error in the optical path of FOG is a critical factor limiting the improvement of gyroscope precision. Through the analysis of Shupe effect, Mohr effect and cross term effect, the mechanism of the thermally induced bias drift error is explained. Factors influencing bias drift are summarized from both internal causes (geometric and physical symmetry) and external causes (environmental impacts and physical field excitation). Furtherly, detection technologies used to detect the key factors (specifically fiber coil strain and temperature distribution) of the internal and external causes, such as Brillouin optical time domain analysis (BOTDA), optical frequency domain reflectometry (OFDR), and Raman optical time domain reflectometry (ROTDR), is reviewed. In the end, various measures and methods to suppress bias drift, including optimization of fiber coil winding processes, application of specialty fibers, adjustment of tail fiber length, and temperature compensation techniques, is discussed. These studies lay a foundation for further improvements in the measurement accuracy and environmental adaptability of navigation-grade FOG under harsh conditions.

The combination of semi-active laser detection guidance and infrared imaging guidance can obtain active and passive detection modes, improving the seeker’s all-weather detection ability, anti-interference ability and target capture tracking ability. The performance of the optical system in the laser infrared composite guidance seekers directly determines the detection range, target recognition and hit accuracy of the guided weapon system. The composite seeker adopts a separate aperture optical system, and each channel adopts a separate optical structure and detector, which is easier to achieve, but it will bring problems such as spatial registration, and the system volume and mass are large. In this paper, a common aperture optical structure is adopted, and the transmittance of laser (1.064 μm) and infrared (8~12 μm) spectral bands is considered, and the composite optical design is achieved by using a focal length matching method to share a fairing and a high transmittance lens. The laser signal is focused through the fairing and the first lens, which is then reflected to the side of the lens barrel by a planar mirror located in the center of the aperture, which is received by a four-quadrant detector. The infrared light signal passes through the periphery of the aperture and is imaged onto an uncooled focal plane detector by three lenses containing diffractive lenses. The whole optical system through -45~60 ℃ no heating design, the overall structure of the optical system is simple and compact, small size, the total length is less than 86 mm, the caliber is less than 62 mm. The optical system design can be applied to laser infrared composite guided rockets, missiles and other weapon platforms, providing technical reserves for high-tech warfare with high efficiency and cost.

The influence of position effect and interface effect on the process of a tungsten alloy rod-shaped penetrator vertically penetrating a ceramic/aluminum alloy composite target plate is studied through experimental research and simulation analysis. The effect of the position effect on the protective performance of the target plate is examined by changing the impact point, while the effect of the interface effect on the protective performance of the target plate is investigated by varying the number of ceramic layers. Research on positional effects shows that when the impact point is within the range of 0 to 30 mm from the ceramic boundary, the penetration depth of the back-plane changes by 9 mm. When the impact point is within the range of 30 to 50 mm from the ceramic boundary, the penetration depth of the back-plane changes by 1 mm. It can be concluded that the protective performance of the target plate in this area is no longer influenced by the position of the impact point. In other words, the area that is greater than or equal to five times the bullet diameter from the ceramic boundary is the effective protection area of the target plate. Research on the interface effect indicates that the penetration depth of the composite target plate with three different structures at the same thickness is 40.32 mm, 47.47 mm, and 50.77 mm; that is, the ceramic protective performance decreases with the increase in the number of layers at the same thickness.

This study commences with an examination of the operational sequence of the secondary fuze in a fuel-air explosive (FAE) munition, analyzing the potential interference factors such as shock waves and electromagnetic radiation, as well as their characteristics, that the secondary fuze may encounter at the terminal phase of the trajectory. Counter-interference design methods for the secondary fuze are proposed from various perspectives, including trajectory design, circuit design, and structural design. Static detonation experiments were conducted to compare the interference-resistance capabilities of the secondary fuze under two different configurations: independent design and cable-connected design. The experimental results indicate that the secondary fuze with an independent structural design exhibits superior interference-resistance, capable of emitting a normal ignition signal at the preset timing following the explosion of the dispersed charge. In contrast, the secondary fuze with a cable-connected design failed to issue an ignition command at the designated moment, resulting in electrical failure of the components within the fuze. It is postulated that the electromagnetic radiation generated by the detonation of the explosive charge enters the fuze through field-line coupling, thereby causing damage to the fuze. Furthermore, the experimental results demonstrate that under the conditions of this study, the pulse interference current induced has a duration reaching the order of hundreds of nanoseconds, with a peak current reaching tens of amperes, which is sufficient to directly inflict damage on the microcontroller and interface circuits of the fuze.

In order to realize the purpose of the tail cover being side-thrown away from the launch axis during the second ignition of the cold catapult missile, a new type of shroud throwing scheme was proposed: the eccentric tail cover and the nozzle outlet were connected by a sealing plug, and the gas jet was used as the power source to realize the side-throwing separation. Considering the influence of different centroid positions and horizontal lateral winds on the separation process, a three-dimensional tail mask separation model was established, combined with the overlapping dynamic mesh technology, the fluid control equation and the rigid body six-degree-of-freedom motion equation were coupled, and the tail cover separation process was numerically simulated. The variation curve of the motion characteristics of the tail cover when it is impacted by the jet and the interference characteristics of the tail cover on the flow field of the gas jet are obtained. The results show that the scheme can achieve the purpose of lateral throwing of the tail cover away from the emission axis. With the increase of the degree of centroid bias, it is beneficial for the jet state at the axis to be stable first. When the centroid position is greater than one-half radius, the jet has a greater accelerating rotation effect on the tail cover than the translational rotation, which increases the instability of the tail cover during the movement, and the tail cover tends to be close to the axis in the later stage of separation. The horizontal lateral wind is conducive to the tail cover to stay away from the axis, and the trend of moving away from the axis is more obvious with the increase of wind speed.

To improve the penetration ability of multiple explosively formed projectiles (MEFP) against armored targets, a double-layer shield axial combination charge structure MEFP is proposed. The MEFP adopts a double-layer liner structure with 1 in the center and 8 double-layer liners in the circumferential direction. During the explosion forming process, the central double layer main cover can form 2 EFPs, and the circumferential 8 double layer auxiliary covers can form 16 EFPs, which can cause multi-point and dual penetration damage to the armor. Based on the feasibility of this structure, numerical simulation is conducted on the formation and penetration process of the MEFP using ANSYS/LS-DYNA software. The effects of factors such as charge height, main (auxiliary) curvature ratio, main (auxiliary) wall thickness, and main (auxiliary) front and rear stage wall thickness ratio on its formation process are analyzed in detail. The good formation results are used for penetration simulation on the 45 # steel target plate. The research results indicate that MEFP is well formed with the charge height being 75 mm, the main (auxiliary) curvature ratio being 1.0 (1.3), the main (auxiliary) wall thickness being 4 mm (2.5 mm), and the ratio of the main (auxiliary) front and rear wall thickness being 0.5. After penetrating two layers of 12 mm 45 # steel target plates, MEFP still has a certain aftereffect penetration ability; When the explosion height is greater than 2 m, the formed MEFP has a multi-point damage effect, and as the explosion height increases, the damage drop radius increases. The research and design of the double-layer cover axial combination charge structure MEFP has important reference significance for the terminal sensitive projectile warhead.

Aiming at the situation that the anti-radiation missile cannot strike the target effectively in the case of sudden radar shutdown, according to the posture of the helicopter implementing the anti-radiation missile attack, the mathematical model of three-dimensional positioning is constructed, and the passive positioning algorithm is obtained by using the improvement of Kalman filtering derivation, and the simulation verification and analysis are carried out for the positioning accuracy of the altitude angle, azimuth angle, as well as the X, Y, and Z directions before and after the addition of the pure inertial guidance and the combination of the navigation error. After adding pure inertial guidance and combined navigation error, the algorithm is simulated to verify and analyze the positioning accuracy in X, Y, and Z directions before and after filtering. The results show that the accuracy of the proposed passive positioning algorithm based on improved EKF is higher than that of the traditional EKF, the positioning accuracy is less than 4%, and the convergence time is less than 30 s, which meets the demand for passive positioning of antiradiation missile targets, and verifies the feasibility of the algorithm.

Video object segmentation is a key task in computer vision and is of great significance to fields such as autonomous driving and video coding. For the video object segmentation, the proposed method utilizes an efficient encoding memory network (EMNet) to achieve semi-supervised video object segmentation. The method includes an adaptive reference frame selection module, a dual path matching module, a feature processing module and a feature aggregation module. The adaptive reference frame selection module takes into account mask confidence and similarity, and selects a reference frame that contains rich information. The dual-path matching module realizes bidirectional and dual-scale matching between query frames and reference frames to improve the accuracy of target feature matching. The feature processing module includes a semantic enhancement module and a feature refinement module, which enhance the semantic and detailed information of the target through low-pass and high-pass filtering. Finally, the feature aggregation module fuses and utilizes each feature. An evaluation is carried out on the DAVIS2017dataset and the result shows that the proposed method is effective.